Malvern Mastersizer 2000 Operation & User’s Manual

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Addendum number ADD0070-2.0 Date 10/03/2010 Manual number MAN0384-1.0 Manual name Mastersizer 2000 User Manual This addendum presents new information on the Mastersizer 2000/2000E from Malvern Instruments. Laser specification The following information adds to the Light Sources information given on page A-1: Red light � CDRH and CE compliant (Class llla laser product (CDRH) / Class 3R laser product (IEC60825-1(1993)+A1(1997)+A2(2001)) � Type: HeNe gas laser. � Max. output power: 4mW. � Beam diameter: 0.63mm (1/e²). � Beam divergence: 1.5mrad. � Beam wavelength: 633nm. Blue Light For the Mastersizer 2000 and Mastersizer 2000LF this is: � Beam wavelength: 466nm. � Type: LED.

Introduction to this manual About this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 Access to the instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 Assumed information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 Where to get help. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4 Overview Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 What the Mastersizer 2000 does . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 How the Mastersizer 2000 works. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 Making measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 Viewing the results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 Saving the results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 Identifying the features Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 Typical systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 Optical bench components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8 Making measurements - a tutorial Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 General measurement advice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 The basics of making a measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 Measurements on a Mastersizer 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 Measurements on a Mastersizer 2000E . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 Measuring new samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16 Measurement options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18 Table of Contents

Mastersizer 2000 Page ii MAN 0384 Viewing the results Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 Displaying the information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Changing views - the Report Designer . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6 Understanding the views Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 Understanding the display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 Report features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 Fundamental concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7 Optical models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14 Handling measurement files Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 Records and files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2 Searching and sorting records. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3 Exporting results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6 Extracting an SOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8 Sample preparation Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 Sample preparation flow chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2 Representative sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3 Considerations for dry samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4 Considerations for wet samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5 Symptoms of poor sample preparation . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

Mastersizer 2000 Page iii Advanced features Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 Obscuration settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2 Advanced result processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5 Editing results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8 Defining user size bands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-9 Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11 Averaging records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-13 Importing results from older instruments . . . . . . . . . . . . . . . . . . . . . . . . 9-14 Result emulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-15

Mastersizer 2000 Page iv MAN 0384 Part 2 - Supervisor’s Guide Security Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1 Security principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2 Setting up the Administrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Security guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4 Setting up user groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5 Setting up individual users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6

Mastersizer 2000 Page v Part 3 - Appendices Specification Optical bench . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1 Chemical compatibility Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1 Unpacking instructions Regulatory statements CE Declaration of Conformity (APA2000) . . . . . . . . . . . . . . . . . . . . . . . . .D-2 CE Declaration of Conformity (EPA2000) . . . . . . . . . . . . . . . . . . . . . . . . .D-3 FCC Notice (US only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-4 Canadian Regulatory Information (Canada Only). . . . . . . . . . . . . . . . . . . .D-5 VCCI acceptance (Japan only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-5 Index

About this manual This manual describes the operation of the Malvern Mastersizer 2000 and 2000E particle size analysers. Information is also given on basic use of the Hydro 2000G and Hydro 2000MU sample dispersion units: For more detailed information on the operation of any sample dispersion unit, see its individual manual. This user manual is a companion to the Mastersizer 2000 Essentials Manual which gives Health and Safety, maintenance and other vital information which all users must read. After reading this user manual, users should understand the basic measurement technique and be able to perform a simple measurement, analyse the data and iden- tify the main features of the system. For users who have never operated a Malvern particle analyser before, we recom- mend reading this manual fully before starting the first measurement. Users who are more familiar with particle size analysers may wish to proceed straight to Chapter 4 which gives details on making measurements. However, the importance of sample preparation before measurement cannot be overstated. We therefore recommend that these users read the chapter on sample preparation (Chapter 8) soon. Instrument Model number Mastersizer 2000 APA2000 Mastersizer 2000E EPA2000 Hydro 2000G AWA2000 Hydro 2000MU AWM2001

Page 1-2 MAN 0384 1 Warning! The instrument and the samples to be measured may be hazardous if mis- used. Users must read the Health and Safety information in the Essen- tials Manual before operating the system. Access to the instrument Within this manual, reference is made to the various people who will have access to the instrument. Below is a list of these people and their responsibility: Malvern personnel Malvern personnel (service engineers, representatives, etc.) have full access to the instrument and are authorised to perform all service procedures that may require the removal of the covers. Supervisor The supervisor is the person responsible for the management/safety of the instru- ment and of its operation. The supervisor is responsible for the training of the operators. The supervisor can perform all user maintenance routines identified in the Essentials Manual, including changing the fuses. Warning! Under no circumstances must the supervisor or operator remove the covers of the instrument. Operator An operator is a person trained to use the instrument. The operator can perform all user maintenance routines in the Essentials Manual except for changing the fuses. Warning! Failure to follow these guidelines could result in the emission of laser radi- ation. Laser radiation can be harmful to the body and can cause permanent eye damage.

Chapter 1 Mastersizer 2000 Page 1-3 Assumed information General The Mastersizer 2000/2000E can be used with a variety of sample dispersion units that allow it to measure wet and dry samples. The function of these is identical: to prepare and deliver the sample to the optical bench for measurement. For clarity, this manual assumes that the primary dispersion unit for each system is as follows: � For the Mastersizer 2000 the Hydro 2000G. � For the Mastersizer 2000E the Hydro 2000MU. For more details of any sample dispersion unit, refer to its manual. Naming convention Within this manual: � The Mastersizer 2000/2000E optical bench is referred to as “the optical bench” or “the instrument”. For simplicity, in general text the term “Mastersizer 2000” refers to both the Mastersizer 2000 and 2000E. Where the Mastersizer 2000E is different, this is always explained. � The sample dispersion units are referred to in full (“the Hydro 2000G” or “the Hydro 2000MU”), or as “the dispersion unit”. � The combination of the optical bench, one or more dispersion units and the computer is referred to as “the system”. Menu commands Menu commands from the Malvern software are referred to in the form main menu-menu item. As an example, the command Configure-New SOP refers to selecting the New SOP item in the Configure menu. The same rules apply for sub-menus of sub-menus, so that Tools-Options-Instrument Port refers to the Instrument Port item in the Options sub-menu, which itself is a sub-menu of the Tools menu. Menu commands are always shown in bold text.

Page 1-4 MAN 0384 Where to get help Other manuals Several manuals are supplied with the system, each giving information on a differ- ent aspect of it. Below is a list of the typical manuals supplied with the system, detailing the type of information in each one. Quickstart Manual This gives a simple introduction to the system and explains how to make a meas- urement. Essentials Manual This manual covers: � Site requirements – all the physical requirements for positioning the system. Information is given on service requirements (air, water, number of power sockets, etc.), environmental requirements (temperature, humidity, etc.) and physical requirements (space needed, etc.). Note The system must be initially commissioned by a Malvern-trained repre- sentative. � Health and Safety – this must be read by all users of the system. It details all safety issues for the optical bench and all dispersion units. � Maintenance – for both the optical bench and dispersion units. � Installation – this gives enough information to allow the user, for example, to move the system from one laboratory to another. Instructions are also given on how to install the Malvern software if the user upgrades the computer system. Caution! If the system is covered by a Qspec validation contract, we strongly recom- mend that it is only moved by Malvern representatives. Autosampler 2000 manual The Autosampler 2000 has its own manual giving details on its use. Dispersion Unit manuals Each dispersion unit has its own manual giving details on its use. i

Chapter 1 Mastersizer 2000 Page 1-5 Online help The primary function of the online help is to give detailed information on the soft- ware. Each dialogue has a Help button that, when pressed, gives help specific to that dialogue. Many dialogues also have Advice buttons, giving more general advice. All help topics can be accessed through the standard help screen by selecting Help- Help topics. From within this screen all help topics can be searched or accessed through the contents list or index. Help desk All queries regarding the system should initially be directed to the local Malvern representative. Be ready to quote: � Model number of the optical bench and dispersion unit(s). � Serial number of the optical bench and dispersion unit(s). � Version of the Malvern software – this can be found by starting the software and selecting Help-About. The serial number of the optical bench can be found inside the sample area (remove the cell first). The serial number of a dispersion unit is found on its rear panel. Contact the United Kingdom help desk if the local Malvern representative is not available. Its direct line is +44 (0)1684 891800. Note This help line is primarily English speaking. Remote support Malvern Instruments offers a remote support service, delivered by an Internet con- nection. Benefits include fast and efficient fault diagnosis, reducing downtime and costs. Online user training is also available, plus software updates. A high speed Internet connection is recommended for making use of this facility. i

Page 1-6 MAN 0384 Malvern website - www.malvern.com The Malvern Instruments website offers a comprehensive range of material charac- terisation resources for use by customers 24 hours a day, seven days a week. Resources include Frequently Asked Questions, a knowledge base and application notes, plus information on other material characterisation solutions that Malvern can provide.

terms: � What the Mastersizer 2000 does. � How the Mastersizer 2000 works. � Making measurements. � Viewing the results. � Saving the results. Most of these points are explained in more detail in later chapters of this manual. What the Mastersizer 2000 does Take a look around. At the paint on the walls, the chocolate on a biscuit, the cement foundations of a building. The stability, chemical reactivity, opacity and material strength of these and many other materials are affected by the size and characteristics of the particles within them. The Mastersizer has been designed to measure the size of these particles or, more specifically, the distribution of different sizes within a sample.

Scientists have for centuries tried to predict the way particles scatter and absorb light. There are many theories and models that the modern particle size analyst can use. One of the simplest theories used is the Fraunhofer model. This model can pre- dict the scattering pattern that is created when a solid, opaque disc of a known size is passed through a laser beam. This model is satisfactory for some particles but it does not describe the scattering exactly. Very few particles are disc shaped and most particles are transparent. The accepted theory which accurately predicts the light scattering behaviour of all materials under all conditions is known as the Mie theory. Mie theory was developed to predict the way light is scattered by spherical particles and deals with the way light passes through, or is adsorbed by, the particle. This theory is more accurate, but it does assume the user knows some specific informa- tion about the particle, such as its refractive index and its absorption. The key point about these theories is that if the size of the particle and other details about its structure are known, the way it will scatter light can be predicted accu- rately. Each size of particle will have its own characteristic scattering pattern, like a fingerprint, that is unlike any other size of particle. So how does the Mastersizer measure the size of particles? It works backward from the above theories by using the optical bench to capture the actual scattering pattern from a field of particles. Then, using the theories, it calculates the size of particles that created that pattern. There are three distinct procedures in measuring a sample on the Mastersizer: 1. The sample is prepared and dispersed to the correct concentration and then delivered to the optical bench. This is the purpose of the sample dispersion units. Sample preparation is the most important stage of making a measure- ment. Remember that, if the sample is poorly prepared (unrepresentative or badly dispersed) then the basic data will be incorrect; no amount of analysis of this data will give a correct answer. 2. The capturing of the scattering pattern from the prepared sample - this is known as the “measurement”. This is the function of the optical bench. The detector array within the optical bench is made up of many individual detectors. Each detector collects the light scattering from a particular range of angles. A typical light scattering pattern is shown below.

tor elements (known as a channel). The detector array takes a “snapshot” of the scattering pattern. Obviously this snapshot only captures the scattering pattern from the particles that are passing through the analyser beam at that particular time. Taking only one snapshot may not give a representative reading of the scattering pattern. To overcome this, the Mastersizer takes many snapshots (known as snaps) and averages the result. Typically over 2000 snaps are made for each measurement, with each snap taking 1ms. 3. Once the measurement is complete, the raw data from it is analysed by the Malvern software using one of the theories mentioned above. Once the data has been analysed the information can be displayed in various ways. Note the following points regarding the measured data and the analysis: � Analysing the measurement data does not permanently alter the data. The measurement data can be re-analysed using different methods over and over again. � The software makes a measurement and then analyses the data automatically. Background data 5 130 120 110 100 90 80 70 60 50 40 30 20 10 0 50 45 40 35 30 25 20 15 10 wet measure, 21/06/98 9:18:18 am Data Graph - Light Scattering

using a Standard Operating Procedure (SOP). SOPs SOPs are user-defined procedures that are easily programmed into the software to allow the same type of sample to be measured in a consistent way. Here all the dif- ficult decisions on measurement strategy have already been made. When the SOP is run, it automatically runs through the defined measurement pro- cedure, prompting the operator to perform tasks (such as adding the sample). The SOP takes full control of the dispersion unit (except any manual unit), making all adjustments and settings (such as pump speed and ultrasonic power). This is the recommended method of operation and is suited to beginners or when routinely measuring the same type of sample. Creating an SOP is very easy. The operator selects Configure-New SOP and the software runs the SOP Wizard. This wizard asks a series of questions, such as: � what are the optical properties of the sample? � what is it suspended in? � how fast should the stirrer be? � how much ultrasonic dispersion is required? � should any additives be added to the sample to aid dispersion? � how is the result to be calculated and displayed? These all combine to define the measurement procedure. Manual measurements But how does a user know how to answer the questions? This information is found by referring to the advice which is available at all stages of SOP creation, as well as by experimentation; making a few preliminary measurements and observing the results. This is the primary function of a manual measurement. Manual meas- urements can be used to make “one-off” measurements or used to “get a feel” for a sample prior to defining an SOP. More details on making measurements can be found in Chapter 4.

Once the measurement information has been gathered and analysed, it can be dis- played in many forms. The Malvern software is supplied with many standard “reports” that each display the information in a specific way. For each report that is displayed on the screen, there is an equivalent “hard copy” report for printing the report information to a printer. Remember that the different reports show the same data in different ways. All data from a measurement and analysis is stored in a “record”. Records are stored in a measurement file. A measurement file can contain one or more records (see Chapter 7 for details on handling measurement files). Before measurement data can be viewed a measurement file must be opened (by selecting File-open and selecting a record). A typical measurement file is shown below: The Records tab is shown initially. Selecting this tab shows all the records within the opened measurement file. One or more records must be selected before a report can be opened. The series of tabs at the top of the window shows the reports that are available. To change between reports simply select another report tab. If the standard reports do not satisfy the user’s specific requirements, custom reports can be built using the Report Designer application. See Chapter 5 for details on using the Report Designer. It is possible to zoom into a graph report. Simply hold down the left button, then slowly move the mouse to draw a “marquee” (from top left to bottom right) around the area to be enlarged. To zoom back out, simply left mouse click on the graph. Details on interpreting the reports and an explanation of the standard reports are given in Chapters 5 and 6.

After making a measurement the user can save the result in a measurement file by selecting File-Save or Save as (an SOP can be configured to automatically save the results to a measurement file). A measurement file has the extension .mea.

Introduction This chapter describes all the physical features of the system. Users will probably not use all of the features described as some are only used for specific dispersion units or applications. This chapter covers: � Typical systems – identifies the main modules of typical systems. � Optical bench components – examines the features of the optical bench in more detail. � Software – identifies the main features of the Malvern software. Detailed information on the dispersion units can be found in their own manuals.

Page 3-2 MAN 0384 3 Typical systems These diagrams show typical systems with their key modules: Mastersizer 2000 ill 7917 Mastersizer 2000E ill 7918 1 3 2 1 3 2 1 3 2 1 3 2

Chapter 3 Mastersizer 2000 Page 3-3 The features shown are: Optical bench  The optical bench is used to collect the raw data used to calculate the size of parti- cles in a sample. One or more sample dispersion units  The sole purpose of a sample dispersion unit is to prepare the sample then deliver it to the optical bench so that it can be measured. Malvern makes many sample dis- persion units to handle many forms of sample, including dry powders and samples dispersed in a liquid. A user may have one or more sample dispersion units, depending on their particular requirements. In the diagrams above: � The Mastersizer 2000 is shown with two dispersion units, a Hydro 2000G on the left and a Hydro 2000 S on the right. � The Mastersizer 2000E is shown with a Hydro 2000MU. The individual dispersion unit manuals identify the dispersion units’ features. Computer system  The computer system is a stand-alone computer that runs the Malvern software. The Malvern software controls the optical bench and dispersion units (apart from the Hydro 2000MU and Scirocco 2000M which are manually controlled). It also analyses the raw data from the optical bench to determine the size of the particles.

Page 3-4 MAN 0384 Optical bench components The main features of the optical bench are shown below: ill 7919 The features are:  Cell area protection cover The cell area protection cover can be swung into position when the cell is not in place to prevent dust and dirt contaminating the cell area optics. It is moved by a lifting action rather than a sliding action.  Protection window The protection window stops dust and dirt entering and damaging the internal detectors. Clean this window periodically (see the Essentials Manual).  Drain The drain allows any spillages within the cell area to exit onto the bench.  Cell The cell is the interface between the sample dispersion unit and the optical bench. The sample measured is passed between two windows that allow it to be analysed by the laser beam. 1 4 5 8 7 3 9 2 4 5 3 2 9 8 7 1 66

Chapter 3 Mastersizer 2000 Page 3-5 Three types of cell are available: � A wet cell used on the Hydro 2000G/S/SM/MU, detailed later in this chapter. � A specialised wet cell (the “micro cell”) used on the Hydro 2000µP, detailed in its manual. � A dry measurement cell used on the Scirocco 2000/2000M, detailed in their manuals.  Power indicator This indicator illuminates when the optical bench is turned on.  End panel The end panel contains all communication connectors for the optical bench. It is detailed below.  Cell holder The cell holder is a “parking” area for the cell when it is not in use. This is supplied when more than one dispersion unit is used on the system. It allows the cell to be removed and stored without the need to disconnect it from the dispersion unit.  Window tool The window tool is used to remove the windows from the cell if they need clean- ing or replacing (see the Essentials Manual).  Backscatter detectors These are two detectors that collect some of the light scattering information from the sample. Ensure that these are kept clean and undamaged; the Essentials Man- ual has details.

Page 3-6 MAN 0384 End panel The features of the end panel are detailed below: ill 7920  Power input socket This is the power input socket to the optical bench from the external PSU.  Optical bench power switch This is the on/off power switch for the optical bench.  COMPUTER connector The RS232 cable from the computer is plugged in here. Data from the optical bench and control commands from the computer are transmitted down it.  ACCESSORY connector Dispersion unit communications connector. The first sample dispersion unit is connected here. It allows the dispersion unit to be controlled by the software. This connector is not used if only manually controlled dispersion units (Hydro 2000MU and Scirocco 2000M) are used.  Air holes These holes allow air to cool the unit. Do not obstruct them. 5 2 1 4 3

Chapter 3 Mastersizer 2000 Page 3-7 Wet cell The features of a wet cell are detailed below: ill 4860  Light shroud This shroud stops light entering the cell area during a measurement. More impor- tantly, it protects the user from laser emissions. Never operate the system if any of the covers is damaged.  Cell The cell has a pair of windows that allow the laser to pass through the sample. The windows can be removed for cleaning/replacement (see the Essentials Manual).  “Cell in” and “Cell out” connectors The sample is recirculated through the cell and back to the dispersion unit. These connectors attach the cell to the dispersion unit. The tubing must be connected correctly. The tube from the dispersion unit to the cell must be connected to the Cell in connector. This allows any trapped air bubbles to rise through the cell. The connectors are colour coded to aid correct connection.  Locking handle The locking handle is rotated anti-clockwise to lock the cell in place. Caution! Never try to lift the optical bench by this handle. 4 3 1 2

Page 3-8 MAN 0384 Software The Malvern software controls the system during a measurement and processes the measurement data to produce a size distribution. There are two software modules: � The main application, described below. This main interface allows the user to define an SOP, run a measurement, display the results and print reports. � A secondary module, the Report Designer, allows the user to create custom reports to display the results. The Report Designer is detailed in Chapter 5. Features of the window The features of the window are detailed below: ill 7752  Menu bar The menu bar contains the main menu headings for all software functions. There are several ways to select an item from the menu bar: � Using the mouse – to select an item from the menu bar, click the left mouse button once on the menu. When the menu list drops down, select an item from the menu list by clicking once on it. 1 2 3 4 5

Chapter 3 Mastersizer 2000 Page 3-9 � Using the keyboard – to select an item from the menu bar, hold down the Alt key and press the letter which is underlined in the command required. For example to use the Measure menu hold down Alt and press m. When a key is used in this way it does not matter if it is upper or lower case; M and m both work, for example. � Using keyboard accelerators – to the right of a menu item name there may also be a note of the accelerator for this item. This is a key or combination of keys which can be used to by-pass the menus. For example, users can press Ctrl and O together to select File-Open... without having to use the main menu and drop down menu. Clicking an item which ends with a row of dots (...) opens a dialogue. Items shown in grey are those which are not currently available.  Toolbar The toolbar contains a selection of buttons for performing common operations. Each button has an equivalent menu command. For example using the button is equivalent to using the File-Open command. To help users identify a button, a short tooltip description of its action is displayed in the status bar when the cursor is moved over it. As with the menu bar, if a button is not available it is shown “greyed out”.  Measurement window The Measurement window displays all the information for a measurement file. Multiple measurement windows can be displayed at a time. The contents of the display area change depending on which report tab is selected.  Report tabs Selecting a report tab displays the data for the selected record(s) in that format. Malvern supplies standard reports that allow the user, among other things, to view the list of records within a measurement file, view the measurement data and view the size distribution as a graph and table. Custom reports can be designed using the Report Designer. Details on interpreting reports can be found in Chapter 6.  Title bar The title bar displays the file name of the currently selected measurement file.

Introduction This chapter describes how to make a measurement. It describes: � General measurement advice – the importance of sample preparation and cleanliness. � The basics of making a measurement – describes both manual and Standard Operating Procedure (SOP) measurements. This section details the procedure for each type of measurement in detail. � Making measurements on a Mastersizer 2000E. � Measuring new samples – what to do for a new material. � Measurement options – describes the series of dialogues which comprise the SOP Wizard. The best way to learn how to use the system is to make a measurement. To get the most benefit from this chapter we advise reading it once, then reading it a second time while following the instructions to make a measurement. To do this, obtain a suitable sample to measure and a suitable dispersant to disperse it in. Ordinary single dairy cream dispersed in water is readily available and should give good predictable results.

Page 4-2 MAN 0384 4 General measurement advice Before making a measurement, note the important general advice given here. Sample preparation Good sample preparation is critical. A representative sample must be taken. Dry powders, for example, tend to separate out if stored for some time or vibrated. The larger particles tend to rise to the top and the smaller particles collect at the bottom of the container. If the sample is taken from the top of the container it will not contain the smaller particles, giving a biased measurement. The sample should be correctly mixed before a measurement is taken. Wet samples also have to be correctly dispersed in a liquid dispersant. Using the wrong dispersant can cause the sample to stick together in clumps, float on the sur- face, or even dissolve. Check the sample and dispersant to see if they are suitable before a measurement is made. There are many ways to prepare the sample to ensure a perfect measurement. Details on sample preparation are given in Chapter 8. Note Over half of the problems encountered in measuring a sample are caused by bad sample preparation. If the user prepares badly for the measurement, no amount of subsequent analysis will give a good result. Adding the sample The software reports exactly what level of signal the sample generates and whether this is ideal, too low, too high, etc. The technique has a wide range of concentra- tions that are ideal so concentrations do not have to be precise. The sample concentration is controlled by monitoring the obscuration of the laser beam caused by the sample. The obscuration is simply the fraction of light “lost” from the main beam when the sample is introduced. For example, an obscuration of 30% means that 30% of the incident laser beam (recorded during the Measure Background step) has been lost through scattering or absorption. The range of concentrations over which the instrument can be used can be expressed in obscuration terms as the following table shows. i

Chapter 4 Mastersizer 2000 Page 4-3 Cleanliness of the optical system Laser scattering is a high resolution optical method in which the detectors and win- dows are an integral part of the measurement zone. Dust or smears on the windows will scatter light that will be measured with the sample scattering. In general the process of measuring both a background and a sample and then subtracting the background corrects for such contributions. However, this correction is first order only and excessive dirt on the optics will degrade the instrument's sensitivity. We recommend ensuring that detectors and windows are clean at all times. See the Essentials Manual for advice on cleaning the system. If in doubt about the optical cleanliness, the user can use the live display of the background measurement. By viewing this screen they can judge whether the optics are clean or not. The basics of making a measurement There are two ways to make a measurement: � Using a Standard Operating Procedure (SOP) – SOPs are user defined procedures that are easily programmed into the software to allow the same type of sample to be measured in a consistent way with all the difficult decisions on measurement strategy already having been made. When the SOP is run, it automatically runs through the defined measurement procedure, prompting the operator to perform tasks such as adding the sample. The SOP takes full control of the dispersion unit (unless it’s a manual unit), making all adjustments and settings (such as pump speeds and ultrasonic power). This is the recommended method of operation and is suited to begin- ners or when routinely measuring the same type of sample. � Manual measurements – used either to make one-off measurements or to try out a sample prior to defining an SOP for it. Follow the section below for the instrument used. Obscuration range (%) Obscuration graph colour Notes <5 red Add more sample. 5-10 orange Low but usable with a good signal to back- ground ratio. 10-20 green Ideal. 20-50 orange Usable but try to add more dispersant - there’s a danger of multiple scattering. >50 red Too high.

Page 4-4 MAN 0384 Measurements on a Mastersizer 2000 Instrument preparation Before starting a measurement, ensure that the correct cell is installed in the cell area then power up the system as outlined below. (If an SOP is run, the software will check that the correct cell is connected, informing the user if it is not). To power up the system: 1. Switch on the dispersion unit(s). 2. Switch on the optical bench. 3. Switch on the computer and start the software by double-clicking on the Mas- tersizer 2000 icon. Making a basic SOP measurement Start an SOP by selecting Measure-Start SOP. In the dialogue which appears select an SOP. The Measurement Display dialogue will appear: ill 7753 1 2

Chapter 4 Mastersizer 2000 Page 4-5 The Status area at the bottom left of the dialogue reports what is going on and what to do next. The information in the dialogue changes depending on the stage of the measurement. The SOP measurement runs as automatically as possible. In a typical SOP measurement there are only three things the user has to do: 1. Part way through a measurement the dialogue asks the user to add sample to the dispersion unit’s tank. Depending on the SOP design, the user is either asked to add a specific quantity to the tank or add sample to the tank until the obscuration bar  is in the green section. 2. Once the correct amount of sample has been added, press the Start button  to start the actual measurement. 3. Depending on the SOP design, a dialogue may appear asking the user to docu- ment the measurement (add comments and observations). If specified, an SOP measurement will automatically clean and fill the dispersion unit, measure the background, align the optics, calculate the size distribution, and save the record to a measurement file. All the user has to do is wait for a prompt from the SOP to perform the actions detailed above. Try making an SOP measurement using single dairy cream. Make sure that the sys- tem is connected and powered up, then: 1. Select Measure-Start SOP and browse for the SOP file. 2. Select Dairy cream using Hydro 2000G.SOP (or Dairy cream using Hydro 2000S.SOP if using the Hydro 2000S) from the directory C:\Program files\Malvern Instruments\Mastersizer 2000\SOP. 3. Select OK. The SOP measurement will start by cleaning the tank. 4. The SOP automatically measures an electrical background, aligns the optical system and measures the optical background. 5. The Add Sample tab appears and the SOP asks the user to add the cream to the tank. Add enough sample (one drop at a time) to make the Laser Obscuration bar show green (try and achieve a mid value). 6. Once satisfied that enough sample has been added, press the Start button. The sample is measured and the result (size distribution) calculated. The measure- ment record is automatically saved to a measurement file. The measurement is complete. Now select the record in the Measurement window and view the results by selecting one of the report tabs.

Page 4-6 MAN 0384 Making a basic manual measurement To make a manual measurement select Measure-Manual. The Measurement Display dialogue shown below will appear: ill 7754 The software will automatically make an electrical background measurement and an optical background measurement then align the optics. The main features of this display are:  The Status area at the bottom left of the dialogue reports what is going on. The information in the dialogue changes as the measurement progresses.  The tabs show information on the four stages of making a measurement: � Measure Background – the measurement data from a particle field is contaminated by background electrical noise and also by scattering data from dust on the optics and contaminants floating in the “clean” disper- sant. The Measure Background facility automatically makes a measure- ment of the system containing only clean dispersant when a manual measurement is started, as well as a measurement of the electrical back- ground. This background information is subtracted from the sample meas- urement in order to “clean” the data. � Add Sample – this tab shows how much sample has been added to the tank for measurement. The system measures how much sample is added by monitoring the “obscuration” of the beam caused by the sample being added to the dispersant. The obscuration is simply the fraction of light “lost” from the analyser beam when the sample is introduced. For example 1 2 3

Chapter 4 Mastersizer 2000 Page 4-7 an obscuration of 30% means that 30% of the analyser beam has been lost by either scattering or absorption. The “obscuration bar”  gives a visual indication of how much sample is added. If the bar is in the green zone the concentration is in the correct range. If it is in the red the concentration is out of range. The exact obscuration is given at the bottom left of the dialogue. The instrument has a wide range of concentrations that are acceptable so concentrations do not have to be precise. The target obscuration values can be set by the user; see Chapter 9. � Measure Sample – this tab displays the scattering information during the actual measurement. � Result – this tab is shown as the software calculates the size distribution.  The toolbar buttons – these allow the user to control the measurement process and document the measurement, control the dispersion unit and set up all the measurement parameters. The buttons are: � Options – this button gives access to the measurement options. For exam- ple, the user can specify what sample and dispersant to measure, how the size distribution is to be calculated, and where to save the results. � Document – pressing this button displays a dialogue where the user can document the measurement i.e. make notes on the pre-dispersion tech- niques, sample quantity, etc. This allows the measurement to be repeated at a later date. � Start – starts a measurement process. For example, after adding the sample and once satisfied with the quantity, the user can start the measurement process by pressing Start. � Stop – this button stops the current measurement process. � Next – pressing Next automatically moves to the next logical stage of the measurement. For example, if the user has just completed a background measurement (and the Pause between stages check box is enabled), pressing Next takes them to the Add Sample tab. � Accessory – pressing this displays a dialogue allowing the user to control the dispersion unit (pump and stirrer speeds, etc.). The system automati- cally detects which dispersion unit and cell are fitted and changes this dia- logue to suit. � Help – pressing this button displays help information. � Close – pressing this button closes the measurement window.

Page 4-8 MAN 0384 A manual measurement test Try making a manual measurement using ordinary single dairy cream. Make sure the system is connected and powered up, then: 1. Select Measure-Manual. The software will automatically make an electrical and optical background measurement as well as aligning the optics. 2. Press the Options button to open the Measurement Options dialogue: Select the Material tab to specify the materials measured. Select Dairy cream from the Sample material name box. (When measuring their own samples, the user would specify a new material by pressing the Materials button). 3. This sample is an aqueous emulsion so it should be dispersed in water. Select Water in the Dispersant name box. 4. Select the Measurement tab (shown below). Change both the Sample meas- urement time and Background measurement time boxes to 5 seconds.

Chapter 4 Mastersizer 2000 Page 4-9 Select OK. 5. In the Measurement Display window press the Next button to add the sam- ple. The display will change. Add one drop of the cream to the tank and wait for it to diffuse through the system. Add enough drops to make the blue Laser Obscuration bar move into the green area (try and achieve a mid value). 6. Once satisfied that enough sample has been added, press the Start button. The sample is measured and the result (size distribution) calculated. The measure- ment record is automatically saved to the records buffer. 7. At the end of the measurement a dialogue appears, asking if the user wants to make another measurement. Select Finished measuring. The Measurement Display disappears and the software returns to the main window. 8. The measurement is now complete. Click on the Records tab, select the record and then select one of the report tabs to view the results in detail.

Page 4-10 MAN 0384 Measurements on a Mastersizer 2000E Instrument preparation Before starting a measurement, ensure that the correct cell is installed in the cell area then power up the system as outlined below. (If an SOP is run, the software will check that the correct cell is connected, informing the user if it is not). To power up the system: 1. Switch on the dispersion unit(s). 2. Switch on the optical bench. 3. Switch on the computer and start the software by double-clicking on the Mas- tersizer 2000E icon. Making a basic SOP measurement Start an SOP by selecting Measure-Start SOP. In the dialogue which appears, select an SOP. The Measurement Display dialogue will appear: ill 7753 The status area at the bottom left of the dialogue always says what is going on in the measurement. The information in the dialogue will change depending on the stage of the measurement. The SOP measurement runs as automatically as possible. In a typical SOP measurement there are only a few things the user has to do: 1 2

Chapter 4 Mastersizer 2000 Page 4-11 1. Pump clean dispersant through the cell using the pump and stirrer controls on the dispersion unit, before starting the measurement. 2. Part way through a measurement the dialogue asks the user to add sample to the dispersion unit’s tank. Depending on the SOP design, the user is asked to add a specific quantity to the tank or add sample to the tank until the obscura- tion bar  is in the green section. Depending on the SOP design, the user may be asked to alter the dispersion unit controls. 3. Once the correct amount of sample has been added, press the Start button  to start the actual measurement. 4. Depending on the SOP, a dialogue may appear asking the user to document the measurement (add comments and observations). If specified, an SOP measurement will automatically measure the background, align the optics, calculate the size distribution, and save the record to a measure- ment file. All the user has to do is wait for a prompt from the SOP to perform the actions detailed above. SOP summary To summarise, an SOP measurement generally follows the steps indicated below. Make sure that the system is connected and powered up before starting. 1. Select Measure-Start SOP. 2. A browse dialogue appears; select an appropriate SOP file from this directory: C:\Program files\Malvern Instruments\Mastersizer 2000E\SOP 3. Select OK. 4. The SOP measurement asks the user to clean the cell and then pump in fresh dispersant using the dispersion unit controls. 5. Press Start when the system is clean and ready to start a measurement. 6. The SOP automatically measures an electrical background, aligns the optical system and measures the optical background. 7. The Add Sample tab appears and the SOP asks the user to add the sample to the tank. Add enough sample (add one drop at a time) to make the blue Laser Obscuration bar show green (try and achieve a mid value). 8. Once satisfied that enough sample has been added, press the Start button. The sample will be measured and the result (size distribution) will be calculated. The measurement record will automatically be saved to a measurement file. 9. The measurement is now complete - the user can now select the record and view the results by selecting one of the report tabs.

Page 4-12 MAN 0384 Making a basic manual measurement To make a manual measurement select Measure-Manual. First fill the beaker with clean dispersant, then use the dispersion unit to pump the dispersant through the cell - this will be prompted by the software. The Measurement Display now appears and the software automatically makes an electrical background measure- ment, followed by an optical background measurement and alignment of the optics. It is worth spending some time to familiarise yourself with this display. The display is shown below and its main features identified. ill 7754 Its main features are:  The status area at the bottom left of the dialogue reports what is going on. The information in the dialogue changes as the measurement progresses.  The tabbed displays show information on the four stages of making a measure- ment: � Measuring a background – the measurement data from a particle field is contaminated by background electrical noise and also by scattering data from dust on the optics and contaminants floating in the “clean” disper- sant. The “measure background” facility makes a measurement of the sys- tem with only clean dispersant in as well as a measurement of the electrical background. This background information is subtracted from the sample measurement in order to “clean” the data. 1 2 3

Chapter 4 Mastersizer 2000 Page 4-13 A background measurement is automatically performed when a manual measurement is started. � Add Sample – this tab shows how much sample has been added to the tank for measurement. The system measures how much sample is added by monitoring the “obscuration”of the beam caused by the sample being added to the dispersant. The obscuration is simply the fraction of light “lost” from the analyser beam when the sample is introduced. For example an obscuration of 30% means that 30% of the analyser beam has been lost by either scattering or absorption. The “obscuration bar”  gives a visual indication of how much sample is added. If the bar is in the green zone then the concentration is in the cor- rect range. If it is in the red then the concentration is out of range. The exact obscuration is given at the bottom left of the dialogue. The instru- ment has a wide range of concentrations that are acceptable and thus con- centrations do not have to be precise. The target obscuration values can be set by the user; see Chapter 9. � Measure Sample – this tab displays the scattering information during the actual measurement. � Result – this tab is displayed when the software is calculating the size dis- tribution.  The measurement control buttons allow the measurement process to be con- trolled and allow the user to document the measurement, control the disper- sion unit and set up all the measurement parameters. The buttons are outlined below. � Options – this button gives access to the measurement options. For exam- ple, the user can specify what sample and dispersant to measure, how the size distribution is to be calculated, and where to save the results. � Document – pressing this button displays a dialogue where the user can document the measurement i.e. make notes on the pre-dispersion tech- niques, sample quantity, etc. This allows the measurement to be repeated at a later date. � Start – starts a measurement process. For example, after adding the sample and once satisfied with the quantity, the user can start the measurement process by pressing Start. � Stop – this button stops the current measurement process. � Next – pressing Next automatically moves to the next logical stage of the measurement. For example, if the user has just completed a background measurement (and the Pause between stages check box is enabled), pressing Next takes them to the Add Sample tab.

Page 4-14 MAN 0384 � Accessory – pressing this displays a dialogue allowing the user to control the dispersion unit (pump and stirrer speeds, etc.). The system automati- cally detects which dispersion unit and cell are fitted and changes this dia- logue to suit. � Help – pressing this button displays help information. � Close – pressing this button closes the measurement window. A manual measurement test Try making a manual measurement using ordinary single dairy cream. 1. Make sure the system (optical bench and Hydro 2000MU) is connected and powered up. 2. Fill the sample beaker with clean dispersant and, using the dispersion unit con- trols, pump the dispersant through the cell. 3. Select Measure-Manual. The software will automatically make an electrical and optical background measurement as well as aligning the optics. 4. Press the Options button to open the Measurement Options dialogue: Select its Material tab and specify the material measured. Select Dairy cream from the Sample material name box. (For their own samples, the user would specify a new material by pressing the Materials button).

Chapter 4 Mastersizer 2000 Page 4-15 5. This sample is an aqueous emulsion so it should be dispersed in water. Select Water from the Dispersant name box. 6. Select the Measurement tab (shown below). Change both the Sample meas- urement time and Background measurement time boxes to 5 seconds. 7. Use the controls of the dispersion unit to set the pump, stirrer and ultrasonics settings as appropriate (refer to the Hydro 2000MU manual). 8. Select OK. The status bar on the bottom left of the window always says what is happening and what to do next. 9. Press the Next button to add the sample. The display will change. Add one drop of the cream to the tank and wait for it to diffuse through the system. Add enough drops to make the Laser Obscuration bar move into the green area (try and achieve a mid value). 10. Once satisfied that enough sample has been added, press the Start button. The sample is measured and the result (size distribution) calculated. The measure- ment record is automatically saved to the records buffer. 11. At the end of the measurement a dialogue appears, asking if the user wants to make another measurement. Select Finished measuring. The Measurement Display disappears and the software returns to the main window. 12. The measurement is now complete. Click on the Records tab, select the record and then select one of the report tabs to view the results in detail.

Page 4-16 MAN 0384 Measuring new samples The above procedures are fine if the SOP is set up or all the parameters for a man- ual measurement specified. For a new material, either create or modify an SOP or set up the options for a new manual measurement. This section outlines how to measure a new sample. Measuring new samples: manual measurement The basic procedure is the same as the demonstration outlined above. When the Options button in the Measurement Display is pressed, the Measurement Options dialogue appears. This dialogue controls all aspects of the measurement: � The Materials tab allows the user to select a different material and dispersant or define the optical properties of new materials. It also allows the user to spec- ify options regarding the result calculation. Note If a material is created or modified, the computer calculates a new scatter- ing model. This usually takes one to 10 minutes, depending on the compu- ter. � The Measurement tab allows the user to set up measurement times and set measurement alarms, etc. Press the Document button in the Measurement Display and use the Docu- ment dialogue to add relevant details that will allow users to repeat the measure- ment in future. All the options available are basically the same as when setting up an SOP. For more details of these options see Measurement options later in this chapter. Measuring new samples: SOP measurements Creating an SOP is easy. The operator selects Configure-New SOP and the soft- ware runs through a SOP Wizard. The SOP Wizard asks a series of questions that combine to define a measurement, such as: � what are the optical properties of the sample? � what is it suspended in? � how fast should the stirrer be? � how much ultrasonic dispersion is required? i

Chapter 4 Mastersizer 2000 Page 4-17 � do any additives need to be added to the sample to aid dispersion (and what quantity)? � how will the result be calculated and displayed? Anyone can create an SOP but typically it is the responsibility of the supervisor. An SOP can be created in one laboratory and then distributed to all Mastersizer 2000 users within an organisation. (All the sites must have the dispersion units the SOP refers to.) Remember that no instrument has to be connected to the computer to write an SOP. The Malvern software can be installed on a remote computer and SOPs cre- ated and edited before they are tried out on an instrument. See the Essentials Manual for details on installing the software on another computer. Editing an SOP An existing SOP can be easily edited, either to correct that SOP or to create a new SOP based on it. To edit an SOP: 1. Select Configure-Existing SOP. 2. A tabbed dialogue appears, each tab corresponding to a SOP Wizard dialogue. 3. Select a tab and change any of the entries as required. 4. Select OK – the changes will be saved. To create a new SOP based on an existing one, the user must first modify the exist- ing SOP using Configure-Edit SOP. Once all the changes have been made, the Save-As dialogue will appear. Save the SOP under a different name Deleting an SOP An existing SOP can also be deleted using Configure-Existing SOP. To delete an SOP: 1. Select Configure-Existing SOP. 2. When the Open dialogue appears select the SOP to delete. 3. Right-click and select Delete. 4. When asked to confirm deletion of the file, select Yes. Alternatively, use Windows Explorer to delete the SOP.

Page 4-18 MAN 0384 Measurement options This section shows each of the dialogues that appear when the SOP Wizard is run and explains the basic options available. As stated above, the choices for the options of both manual and SOP measurements are basically the same; most information in this section applies equally to manual measurements. More details on how to select these options can be found in the online help, accessed by pressing the Help or Advice button in any dialogue. A series of dialogues, listed below, is displayed in the SOP Wizard. Identical tab versions of these dialogues are displayed during a manual measurement. Sampler Selection dialogue Use this dialogue to select a sample dispersion unit: Up to two samplers (designated A and B) of each type can be selected, allowing for two different configurations. This may be appropriate, for example, if a specific sampler is dedicated to one sample material or dispersant. Clicking on the Sample handling unit list box displays a list of available samplers. Selecting one of these closes the box. For advice on the choice of sampler, click the Advice button.

Chapter 4 Mastersizer 2000 Page 4-19 All dispersion units are listed - even those that are not attached to the system. This allows an SOP to be written remotely from the system. Note The versions of the following dialogues actually seen may differ slightly, depending on the dispersion unit selected. Material dialogue This dialogue has two sections, Optical properties and Result calculation: Optical properties Use this section to define the optical properties of the material measured. The sys- tem has a large database of commonly used materials, from which a Frequently Used list may be created. The material and dispersant to be used in a measurement are selected from the frequently used sample/dispersant list boxes. The Refractive Index and Absorption of each item listed is displayed next to the list box. Changes to the frequently used lists can be made by clicking on the Materials or Dispersants buttons which open up the material/dispersant databases. This is also the area where additional materials can be defined or existing ones modified. i

Page 4-20 MAN 0384 Materials and dispersants listed may have a small icon beside their entry in the lists: � A red star – these items cannot be deleted or modified. They have special sig- nificance either because they are commonly used, such as water, or they have been generated in a special way, such as the Fraunhofer particle type. � A small Malvern logo – these items can be deleted or modified but a warning is displayed first. Items marked in this way have been added by Malvern Instru- ments and are thought to have universal application. Examples are Polystyrene latex and Propan-2-ol. The initial installation of the Mastersizer 2000 software includes other particle materials and dispersants not marked with the icons described above. These are examples used at Malvern Instruments; delete these if they are not appropriate. Result calculation The process of result calculation can be configured in a number of ways, depending on what is known about the sample. Clicking on the Models button enables selec- tion of one of three models, General purpose (default), Multiple narrow modes or Single mode. Clicking on the Advanced button allows the selection of reduced ranges or spe- cific result transformations. Click on the relevant Advice button for advice. Note (Mastersizer 2000 only) The Mastersizer 2000 uses red and blue light to measure samples. For cer- tain materials (most notably certain inks and pigments) the sample has substantially different refractive indices in red and blue light. This is nor- mally due to the material being highly absorbing in one of the two wave lengths. In these cases it is necessary to enter both refractive indices. For most materials, there is no need to enter a blue refractive index. If a blue refractive index is not given, the Mastersizer assumes that it has the same value as the red refractive index. Blue refractive indices can be found from papers and textbooks in the same way as red refractive index information. When no information is available, determine the most appro- priate choice of refractive index by looking at the fit and residual reports and comparing the results obtained with other observations, e.g. micro- scope images. i

Chapter 4 Mastersizer 2000 Page 4-21 Labels dialogue This dialogue allows an identifier for the sample to be added, uniquely identifying its source. This allows the sample to be traced in the future. This dialogue also allows messages to be displayed for the operator before and/or after a measurement. For example, it may be necessary to give details on how to prepare the sample before a measurement starts, or how to dispose of it after the measurement.

Page 4-22 MAN 0384 Report/Saving dialogue The Report/Saving dialogue can be set to allow the results to be printed once a measurement has been made. Use the Reports page list box to select the report to use. If distributing the SOP to other users, ensure that they have the requested report installed. This dialogue also allows results to be exported to a spreadsheet or other external application. See Exporting results in Chapter 7 for more details.

Chapter 4 Mastersizer 2000 Page 4-23 Measurement dialogue Use the Measurement dialogue to set the measurement and background times. Changing the measurement time automatically changes the Measurement snaps box (there are 1000 measurement snaps per second). The optimum measurement time depends on the size of the sample, its particle size distribution and the dispersion unit used. If a material is monomodal, its essential particle size characteristics can be captured in fewer snaps than a material with a broad particle size distribution which will need to be measured for longer to ensure that the coarser particles have had time to flow through the measurement beam. This dialogue also gives access to some advanced features and alarms. See Chapter 9 for more details.

Page 4-24 MAN 0384 Sampler Settings dialogue The contents of this dialogue depend on which dispersion unit was selected in the Sampler Selection dialogue: Use the dialogue to set all dispersion unit control settings. See the appropriate dispersion unit manual for more details.

Chapter 4 Mastersizer 2000 Page 4-25 Measurement Cycles dialogue Use the Measurement Cycles dialogue to set up repeat measurements and set up tank cleaning and dispersant degassing. This diagram shows the features: ill 7760  Cleaning It is possible to set up the SOP so that the tank and cell are cleaned together: � Before each aliquot. � After each aliquot. � Before and after each aliquot (select both check boxes). Selecting the relevant Enable box causes a clean sequence to be performed. If the sample/dispersant used is not normally removed with a single flush, enter a number in the Flush cycles box to run the flush sequence that number of times. The user can set the Clean mode to either Automatic or Manual. Manual ena- bles the user to clean the system easily using a beaker and a bottle of clean solvent. A series of prompts guides the user through the cleaning cycle.  Dispersant degassing Selecting the Enable check box causes a degassing routine to be performed each time the tank is cleaned. The degassing routine uses ultrasonic action to help remove dissolved gases from the dispersant. 1 2

Page 4-26 MAN 0384 Quantities dialogue Use this dialogue to define the quantities of sample/additives to be added during a measurement.

Introduction Once the result has been calculated, the data can be displayed in many forms. Each way of displaying the data is known as a report. Each type of report has a tab in the Measurement window; to view the data in another report simply select the appropriate tab. This chapter covers: � Displaying the information – the reports provided and the use of the Records tab. � Using the Report Designer to create custom reports. Note All the tabs in a Measurement window display the same measurement data but in different formats. Malvern provides several default reports, identified by the “(M)” in their name, that will be sufficient for most users. The user can also create their own custom reports as required. Generally a computer monitor displays information in a landscape format while a printer prints in a portrait format. Therefore, each report is split into two formats- one for displaying the report on the screen, and another configured for a printer. It is possible for the screen and print formats to be configured to report different information. A report file has the extension .pag. The file holds both the screen and print varia- tions. Chapter 6 gives details on interpreting the information in a report. i

Page 5-2 MAN 0384 5 Displaying the information Open a measurement file by selecting File-Open. Once a file has been selected, a Measurement window will appear. A typical Measurement window is shown below. The information displayed for a measurement is controlled by the tabs. The first tab is always Records. This lists all the measurement records (individual measurements) that are held in that measure- ment file. The user must select a record before it can be displayed. To view the record’s data in a report, select the record then select a report tab. Some reports allow the user to compare or display more than one record. For example, if the user selects more than one record in the Records tab and then selects the Sample data report tab, a graph will show the sample data for all selected records over-plotted on a single graph. The format of the information in a report can often be changed by selecting an item and right-clicking the mouse. For example, selecting the table in a Result Analysis report and right-clicking lets the user change the report to a “Result-in %”, “Result- over %” or “Result-under %”, format (see Chapter 6 for details of the reports). Changes to the graph and table format will be reflected in any printouts of the selected report.

Chapter 5 Mastersizer 2000 Page 5-3 Default reports The default reports supplied by the software are the following. Result Analysis report This report displays the calculated particle size distribution for the selected record. Parameter report This report displays the measurement parameters for a record. It contains items such as sample details, measurement options, whether any alarms have been trig- gered, etc. Sample fit report This report shows how well the analysis data was fitted to the measurement data. It gives an indication of how well the optical properties for the material were described. For example, if the user had to predict the absorption value for a sample, a bad choice will result in large differences in the fit. Sample data report This report displays the basic measurement data. It shows the background signal measured and the actual measurement data. This report can be used to identify problems with measurement data. For example, dirty optics will result in a poor background signal (i.e. one with high values). Result Difference report This report compares two records and displays the difference. The first record must be set as the reference by selecting it, then right-clicking and selecting Set reference result. Sieve reports (British standard and ASTM) These two reports convert the measurement data so that they can be directly com- pared to the equivalent sieve standard. Result Statistics report This report displays various statistics comparing two or more measurements. Fit report This report shows how well the analysis data was fitted to the optical model. Grade Efficiency report This report shows grade efficiency data. The online help gives more information on this.

Page 5-4 MAN 0384 Changing the Records tab By default the Records tab displays seven fields which include Record number, Sample name, Source, Measured on, etc. The record tab can be customised by adding or removing any of the fields that are stored with the measurement record. The order in which the fields are displayed can also be rearranged. Adding a field to the Records tab There are two ways to add a field to the Records tab: � Using the Show Fields dialogue – this is accessed by selecting View-Select Fields (or right-clicking on the list header). The dialogue is split into two sides. The list box on the left shows all fields available that can be added to the records tab. The Show these fields in this order list shows all the fields that are currently displayed in the Records tab. The order in which they are listed is the order in which they appear in that tab. To add a field to the Records tab, select a field from the Available fields list box and press the Add button. � Using Field Chooser – this is a drag and drop facility that allows the user to select a field from a list and then drop it directly onto the records tab. The field chooser can be accessed by selecting View-Field Chooser (or right clicking on the list header).

Chapter 5 Mastersizer 2000 Page 5-5 Removing a record from the Records tab There are two ways to remove a record from the Records tab: � Using the Show Fields dialogue, select the field to remove from the right- hand list, then press the Remove button. � Selecting the header of the field, dragging the header off the page and then releasing the mouse button. Changing the order of records in the Records tab There are two ways to rearrange the records in the Records tab: � Using the Show Fields dialogue, select the field to move in the right-hand list, then use the Move Up and Move Down buttons to change its order. � Directly from within the Records tab by selecting the header of the field and dragging it to a new position. A red arrow will show the insertion point. Be careful to only release the header while a red arrow is displayed, otherwise the field may be removed from the Records tab.

Page 5-6 MAN 0384 Changing views - the Report Designer Using the Report Designer, custom reports can be designed by the user. These provide a standardised output for the result of a selected measurement record which can be tailored to the user’s needs. Two views must be edited due to the different aspect ratios of the printed page and the computer screen. The Page Layout shows the printed version and the Screen Layout shows the screen display. This allows addition of picture objects such as company logos to printed reports while not showing them on the screen display. To add items to a report, use this Tools box or Control Palette: Use the following buttons on the palette to add the listed elements to a report: Button Use this to add: Text. Picture – bitmaps, GIFs, JPEGs, metafiles and icons. Parameter (any parameter used by the Mastersizer system). Conditional expression – can be used to make pass/fail decisions. Calculated quality parameter. Custom calculation. Grade efficiency parameter. Sample pot barcode. Graph – several types are available, as described below. Table – several types are available, as described below.

Chapter 5 Mastersizer 2000 Page 5-7 The toolbox can be moved anywhere on the screen. It can be switched on and off using View-Control Palette. Opening a report Select Tools-Report Designer to start the Report Designer application. Reports can be saved and opened using the menu options File-Save and File-Open. The default file extension is *.pag. A report must be saved in the ../pages directory if the report is to be listed in the report tabs of a measurement file. Creating a report To add an item, click on its button in the Control Palette. When a button is selected an area can be dragged on the report which will then contain the selected item. Once objects are placed on the report screen they can be manoeuvred by selecting and dragging. They can also be reduced or expanded in size using the cursor and tag boxes on the selected object. The Report Designer has many size and alignment tools, available from the tool- bar or using the Layout option on the menu. The following functions operate on two or more selected objects. The last object selected becomes the reference object. � Align left � Align right � Align top � Align bottom � Make same width � Make same height � Make same size The following two functions can be used when two or more objects are overlaid. Using these functions, the selected object can be moved to the front or back of the overlay: � Send to front � Send to back Objects can be selected individually by a left click on the mouse button, cumula- tively by holding down the Shift key while clicking the mouse button or in a group

Page 5-8 MAN 0384 by “marquee selection”, dragging a box over a group of items. If an item has been overlaid by another item and cannot be selected, use the tab key to step through all the items one-by-one until it appears. Changing an item’s properties Set the properties of any added element by selecting it and double-clicking to open the Properties dialogue(s). The online help in the dialogues details how to use each one. Graphs and reports The font type and size of text within a report can be altered using the Properties Box for the selected item. Graphs Multiple data graphs can be added to a report. The following graph types can be added: � Data graph – shows the data produced by the measurement. The data can be displayed in a number of ways which can be altered using the properties box. � Result Difference graph – shows the difference in result between two or more measurement records. A reference record must first be selected. � Result graph – shows the particle size result of the measurement. It can be displayed in different ways using its properties box. � Statistics graph – shows statistics of the result. The parameters available are mean, standard deviation, maximum and minimum. � Trend graph – allow the measurement data from multiple records to be com- pared to investigate any trends in the information. � Grade efficiency graph – grade efficiency curves created from particle sizing results are used to establish the efficiency of separators such as hydrocyclones, sedimenting centrifuges or gravitational clarifiers. The properties of a graph can be altered using its Properties Box. The properties are: � Colour – the colour of the background and/or grid can be modified using the colour sets available. A custom colour can also be created. � Axes – the axes of the graph can be modified. The X and Y axes have optional grid lines. The Y axis can be set to autoscale. � Display – the display can be set to show combinations of data, background and fit. The display can be shown as a histogram or curve.

Chapter 5 Mastersizer 2000 Page 5-9 Selecting the graph tips check box allows the setting of pop up tips (flags showing data points on the graph). These appear on the report itself (not on the screen shown in the Report Designer). Selecting the legend check box places a summary table, showing date and name, at the foot of each graph. Tables A number of data tables can be added to the report. The data is taken from the cur- rent selected record or, for the Difference and Statistics tables, group of selected records. The following data tables can be added: � Data – displays the raw data produced by the system. � Difference – shows the difference between the results in a reference measure- ment record and the currently selected measurement record. � Data Fit – gives a table showing the fit. This shows the difference between the actual light energy distribution measured for a sample and the theoretical pre- diction of the light energy distribution according to the Mie or Fraunhofer scattering model selected for that material. The closeness of the fit is an indicator of the correctness of the light scattering data used and the quality of the measurement (cleanliness of the system, etc.). � Result – shows the raw result data. � Statistics – shows the mean, standard deviation, maximum and minimum of a group of selected measurement records. The statistic shown on the table can be altered using the Properties box. � Sieve – presents the data from the current measurement record as it would be displayed if a stack of sieves had been used for the measurement. A number of standard sieves can be selected using the Properties box. � Phi – soil scientists often use this size classification to present size data. This phi notation is based on a power of two series where the class boundaries are labelled by the index. � Grade efficiency – grade efficiency curves created from particle sizing results are used to establish the efficiency of separators such as hydrocyclones, sedi- menting centrifuges or gravitational clarifiers. The table’s colour, font and number of rows and columns can be altered using its Properties box.

sizer. It covers: � Understanding the display – runs through some of the terms and expressions used in the standard views. � Report features – explains the statistics which reports show. � Fundamental concepts – explains some important concepts the user should understand before proceeding. These include: � How the concentration (Cv) is calculated. � Use of volume-based results. � How the result is expressed in terms of equivalent spheres. � How the distribution parameters are derived. � Optical models – contrasts the Fraunhofer approximation used in some instru- ments with the Mie theory which underpins Mastersizer 2000 operation

Page 6-2 MAN 0384 6 Understanding the display The result from the analysis is the relative distribution of volume of particles in the range of size classes. From this basic result the statistics of the distribution are cal- culated. The result is also interpolated so that the result at points in between the size class boundaries is available. The cumulative undersize and oversize, frequency curves and histograms are obtained from the interpolated result. Once the data has been analysed, the information can be displayed in various ways. Usually the display shows a graph of the result or a table showing the same infor- mation in a tabular form. This diagram shows four of the more common graph types for displaying the result: ill 4948  Histogram – displays the result in the form of “in band” percentages. Each bar in the graph represents a size band of particles (52 - 59 microns for example) and the height of the bar represents the percentage of the sample that is within that band. Read the percentage from the left-hand axis. Unless the size bands are changed (see Chapter 9), the initial analysis uses the size bands that are set by the physical design of the detector.  Result-under plot (also known as cumulative undersize or result less than) – displays the result in the form of “% of sample below a certain size of particle”. For example, by reading the values from the graph (right-hand axis) the user may be able to determine that 10% of the sample is under 23 microns. The exact value can be read from the table accompanying the graph or using a graph tip (position the mouse pointer over the graph and a tooltip appears, showing the size data). The result-under plot is calculated from the initial size bands by fitting a curve to the analysis data so that values within a size band can be read. Particle Diameter ( m.) µ Volume % 0 10 20 0 10 20 30 40 50 60 70 80 90 100 10.0 100.0 4 3 2 1

Chapter 6 Mastersizer 2000 Page 6-3  Result-over plot (also known as “cumulative oversize”) – similar to the result-under plot except that the result is in the form “% of sample above a cer- tain size of particle”. For example by reading the values from the graph (right- hand axis), the user may be able to determine that 90% of the sample is above 23 microns.  Frequency curve – this is calculated by differentiating the result-under/ cumulative undersize curve. The frequency curve is particularly useful for dis- playing the results to show the “modes” or peaks in the graph. The peak of the frequency curve gives the modal diameter, the most com- monly occurring particle diameter. Note that the frequency curve is scaled to be approximately the same height as the analysis size band histogram. Several peaks in the graph indicate that there are distinct sizes of particles within the sample. This “at a glance” inspection of the results is difficult if the result is shown as a cumulative plot. Another use for frequency curves is to compare results from different measure- ments. Other graph types can be over-plotted but the results may be confusing.

Page 6-4 MAN 0384 Report features A typical report is shown below, followed by a brief description of the key features:. ill 7755  The residual is an indication of how well the calculated data was fitted to the measurement data. A good fit is indicated by a residual of under 1%. A residual of over 1% may indicate use of incorrect refractive index and absorption values for the sample and dispersant.  The statistics of the distribution are calculated from the results using the derived diameters D[m,n] - an internationally agreed method of defining the mean and other moments of particle size. See British standard BS2955:1993 for more details. 1 2 3 4 5 6 7 8 9 10 D m n [ , ] Vidi m – 3 ∑ Vidi n – 3 ∑ ---------------------------- 1 m – n ------------- =

Chapter 6 Mastersizer 2000 Page 6-5 D(v, 0.5), D(v, 0.1) and D(v, 0.9) are standard percentile readings from the analysis. � D(v, 0.5) is the size in microns at which 50% of the sample is smaller and 50% is larger. This value is also known as the Mass Median Diameter (MMD) or the median of the volume distribution. The v in the expression D(v, 0.5) shows that this refers to the volume distribution. This can be replaced by s for surface, l for length or n for number distributions. � D(v, 0.1) is the size of particle below which 10% of the sample lies. � D(v, 0.9) is the size of particle below which 90% of the sample lies.  D[4,3] is the Volume Weighted Mean or Mass Moment Mean Diameter.  D[3,2] is the Surface Weighted Mean, also known as the Surface Area Moment Mean Diameter or Sauter mean.  The Span is the measurement of the width of the distribution. The narrower the distribution, the smaller the span becomes. The span is calculated as: The x is replaced by any of the letters v, s, l or n that define the distribution type.  Concentration – the volume concentration. This is calculated using Beer- Lambert’s law. For full details see the following section.  Obscuration – this helps the user to set the concentration of the sample when it is added to the dispersant. It is a measure of the amount of laser light lost due to the introduction of the sample into the analyser beam. The obscuration term can be expressed mathematically: Ls is the light intensity measured in the central detector when a sample is present in the cell, Lb is the same but with clean dispersant (i.e. with no sam- ple). Obscuration is usually expressed as a percentage: 100 x Ob. An ideal range is between 3 and 20%, depending on the sample and dispersion unit used. Span d x 0.9 ( , ) d x 0.1 ( , ) – d x 0.5 ( , ) ------------------------------------------------ = Ob 1 Ls Lb – ----- =

Page 6-6 MAN 0384  Distribution – shows the type of distribution the analysis has used. Options include change from volume to surface area, length or number. Remember that the Mastersizer measurement is fundamentally a measurement of the vol- ume distribution - transforming the result into a surface, length or number dis- tribution is a mathematical process that may amplify any error in the original result, especially at the fine end of the size distribution.  Uniformity – a measure of the absolute deviation from the median. Here d(x,0.5) is the median size of the distribution (where x is replaced by v, s, l or n) and di and xi are respectively the mean diameter of, and result in, size class i.  Specific Surface Area (SSA) – the total area of the particles divided by the total weight. where Vi is the relative volume in class i with mean class diameter of di and p is the particle density. If the SSA is used, it is important that the density of the material is defined (on the SOP Wizard’s Material dialogue). This figure is a mathematical calcula- tion based on the assumption that the particles are both spherical and non- porous. Uniformity Xi d x 0.5 ( , ) – di ∑ d x 0.5 ( , ) Xi ∑ ------------------------------------------------ = SSA 6 Vi di ----- ∑ p Vi ∑ ----------------- 6 pD 3 2 [ , ] --------------------- = =

Chapter 6 Mastersizer 2000 Page 6-7 Fundamental concepts To understand the meaning of the results from the Mastersizer, a number of fun- damental concepts require explanation. These are: � How the concentration is calculated. � The results are volume-based. � The result is expressed in terms of equivalent spheres. � How the distribution parameters are derived. Calculating the Concentration (Cv) Beer-Lambert law The software uses the Beer-Lambert law to calculate the concentration of the sam- ple. This may be expressed as: Where: � I is the intensity of light at a distance b in the particle field of absorbance α. � I0 is the intensity of the light beam as it enters the particle field. � I / I0 is the relative transmission T of the beam (measured directly by the instrument). I0 is the intensity of the laser beam measured at the receiver when no sample is present and I is the intensity with sample in the beam. Expressing the Beer-Lambert law in terms of relative transmission and re-arranging to solve for absorbance gives: (1) Volume concentration The term α contains information about the concentration and size of the particles. From scattering theory the light attenuated by a particle i may be described by: Where: � Qi is the efficiency of light extinction (by scattering and absorption), calculated from Mie theory for a particle of radius ri. I I0 ---- e αb – = α –1 b------Ln T 〈 〉 = ai Qiπri 2ni =

Page 6-8 MAN 0384 � The second term is the cross-sectional area of the particle and the final term ni is the number of particles of radius ri. In terms of the volume of particles , the equation above becomes, for an ensemble of particles: The size of the particles is expressed by the diameter d and the volume terms can be separated into a relative volume distribution v and a total concentration Cv (total volume of particles in a unit volume of dispersant). The equation then becomes: Substituting the above into equation (1) and solving for the concentration gives: If d is measured in µm and b in mm, and v is the relative concentration of the size distribution (such that ) then: This equation provides the concentration in parts per million (ppm). To calculate the value as a percentage volume concentration, the final value is divided by 10,000. In the above equation: � The Transmission (T) is a value between 0 and 1 and is measured directly by the instrument. � The particle size distribution vi is the relative volume in size-class i with mean diameter di. � Qi - the mean extinction term for size-class i - is calculated from scattering the- ory and is a function of the optical properties of the particle and dispersant media. Vi 4 3--πri 3ni = αi 3 4-- QiVi ri ∑----------- = αi 3 2--Cv QiVi di ∑----------- = Cv 2Ln T ( ) – 3b Qivi di ---------- ∑ ------------------------ = ∑vi 1 = Cv ppm ( ) 2000Ln T ( ) – 3b Qivi di ---------- ∑ ------------------------------ =

Chapter 6 Mastersizer 2000 Page 6-9 Concentration at different obscurations This advice gives an approximate idea of the obscuration ranges to use during a measurement. It is possible to convert the obscuration limits into an equivalent volume concen- tration but there is a strong size dependence that makes it difficult to use the data at the time of measurement. The relative volume concentrations of monomodal (sin- gle sized) particles that would give a certain obscuration is illustrated below. The actual curves differ according to the presentation being used. It will be clear that there is a size dependence; an obscuration of 30% means a widely varying volume concentration dependent on size. Concentration at different obscurations Calculated for glass beads in water (n=1.54 +i0) in water In the more realistic situation of a polydisperse (or multimodal) sample it is not possible to provide simple graphical correlations of volume concentrations and obscuration. The system calculates concentration, however, using the size distribu- tion result and the obscuration. For a polydispersed sample the curve of the above figure can be used if the Surface Weighted Mean (D[3, 2]) of the material is taken as single size.

Page 6-10 MAN 0384 Volume-based results The first, and probably most important, point to remember in interpreting results is that the fundamental size distribution derived by this technique is volume-based. This means that when a result indicates, for example, that 11% of the distribution is in the size category 6.97-7.75 microns, this means the total volume of all particles with diameters in this range represents 11% of the total volume of all particles. It is useful to consider a numerical example to illustrate this point. Suppose, for simplicity, that a sample consists of only two sizes of particle, 50% by number hav- ing a diameter of 1 micron and 50% by number a diameter of 10 microns. Assum- ing that the particles are spherical, the volume of each of the larger particles is 1000 times the volume of one of the smaller ones. Thus, as a volume distribution, the larger particles represent 99.9% of the total volume. The graph below illustrates this for a more realistic distribution: ill 1874 % 30 Particle Diameter (µm.) 0 10 20 0.1 1.0 10.0 100.0 1000.0 10000.0 1 2 1

Chapter 6 Mastersizer 2000 Page 6-11 Equivalent spheres Mie theory presumes that the particles measured are perfect spheres. In practice they are very rarely so. This causes a problem in the definition of the term “meas- ure the particle’s size”: if the particle is an irregular shape, which particular dimen- sion should be measured? As an example, imagine that I give somebody a matchbox and a ruler and ask them to tell me the size of it. They may reply by saying that the matchbox is 50mm x 25mm x 10mm. They cannot say that “the matchbox is 25mm” as this is only one aspect of its size. It is not possible to describe the three dimensional matchbox with one unique dimension. Obviously the situation is even more complex for irregular shaped particles such as grains of sand or the pigment particles in paint. Most people want a single measurement to describe their sample, for example, they wish to say that their sample is made up of 50 micron particles. What is required is a unique number that describes the particle. There is only one shape that can be described by one unique number and that is a sphere. If we say we have a sphere of 50 microns, this describes it exactly. We cannot do the same even for a cube as 50 microns can refer to its edge or to a diagonal. One way to get a single unique number to describe an irregular shaped particle is to compare some feature of the actual particle to an imaginary spherical particle. Some typical methods of doing this are: � Equivalent surface area – calculating the diameter of a theoretical sphere that has the same surface area of the original particle. � Equivalent maximum length – this is where the diameter of a theoretical sphere is the same as the maximum dimension of the original particle. � Equivalent minimum length – this is where the diameter of a theoretical sphere is the same as the minimum dimension of the original particle. There are many other methods available to do this. This technique is known as “equivalent spheres”. The Mastersizer uses the volume of the particle to measure its size. In the example above, the matchbox has a volume of 50 x 25 x 10mm = 12500mm3. If the Master- sizer was able to measure this size of “particle” it would take this volume and calcu- late the diameter of an imaginary sphere that is equivalent in volume - in this case it will be a sphere of about 30mm diameter. Obviously the answer will be different if the surface area or maximum dimension of the matchbox is used to calculate an equivalent sphere. All of these answers are correct but each is measuring a different aspect of the matchbox. We can therefore only seriously compare measurements that have been measured using the same technique.

Page 6-12 MAN 0384 Consider a cylindrical particle of diameter 20 microns and length 60 microns. The volume of the cylinder is: ill 7973 The sphere of equivalent volume would have a diameter centred on: with a spread from 20 to 60mm. It is interesting to compare this with other techniques. Sieving would pass the par- ticles through a 20mm aperture and classify them as 20mm. Sedimentation would give a result related to the total surface area, in this case reporting a diameter of around 40mm. If there’s a need to correlate laser diffraction results with values from some other technique, consider applying a shape correction using the Result Modification procedure built into the Malvern software. V π 10µm ( )2 60µm ( ) = 6V π 3 ------- 33µm =

Chapter 6 Mastersizer 2000 Page 6-13 Derived distribution parameters The third point is that the analysed distribution is expressed in a set of size classes which are optimised to match the detector geometry and optical configuration giv- ing the best resolution. All parameters are derived from this fundamental distribu- tion. Distribution parameters and derived diameters are calculated from the fundamen- tal distribution using the summation of the contributions from each size band. In performing this calculation the representative diameter for each band is taken to be the geometric mean of the size band limits: This number will be slightly different to the arithmetic mean: For example, the size band 404.21 - 492.47 microns has a geometric mean of 446.16 microns and an arithmetic mean of 448.34 microns. In most cases the difference is small but the geometric mean is chosen in these calculations as more appropriate to the logarithmic spacing of the fundamental size classes. The same principle of calculation applies to the distribution statistics standard devi- ation, skewness and kurtosis, as shown below: standard deviation skewness kurtosis di l – di di – l + di 2 --------------------- σ Xi di – d ( ) 2 ∑ Xi ∑ ---------------------------------- D K + 2 K [ , ]2 D K + 1 K [ , ]2 + = = Skew Xi di – d ( ) 3 ∑ σ3 Xi ∑ ---------------------------------- D K 3 K + , [ ]3 d d 2 + 3σ2 ( ) – ( ) σ3 ------------------------------------------------------------------------- = = Kurt Xi di – d ( ) 4 ∑ σ4 Xi ∑ ---------------------------------- – 3 D K 4 K + , [ ]4 d 4D K 3 K + , [ ]3 3d 3 6dσ2 + + ( ) – ( ) σ4 -------------------------------------------------------------------------------------------------------------------------- – 3 = =

Page 6-14 MAN 0384 In the above formulae K and X depend on the distribution being calculated as shown in this table: The various derived diameters are related by: For “mono-size” distributions such as latex, the distribution mean is reported as the geometric mean of the size class and standard deviation, skewness and kur- tosis are reported as zero. The procedure used for other parameters of the distribution is to create a spline fit to the fundamental result. Intermediate values are then read from this curve allow- ing interpolation of percentile points which do not coincide with the measurement size band boundaries. Optical models This section contrasts the Fraunhofer approximation used in some instruments with the Mie theory which underpins Mastersizer 2000 operation. Fraunhofer approximation Older instruments and some existing instruments rely on the Fraunhofer approxi- mation only. This assumes that: � The particle is much larger than the wavelength of light employed. ISO 13320 defines this as being greater than 40x wavelength (25µm when a He-Ne laser is used). � All sizes of particle scatter with equal efficiencies. � The particle is opaque and transmits no light. These assumptions are incorrect for many materials and for small particles they can give rise to errors approaching 30%, especially when the relative refractive index of the material and medium is close to unity, or when the particles are transparent. Distribution K Xi Volume 3 Vi Surface 2 Vi /di Length 1 Vi /di 2 Number 0 Vi /di 3 D m n [ , ]m – n D m 0 [ , ]m D n 0 [ , ]n ----------------------- =

Chapter 6 Mastersizer 2000 Page 6-15 When the particle size approaches the wavelength of light the scattering efficiency becomes a complex function with maxima and minima present. Mie theory The Mastersizer 2000 uses the full Mie theory which completely solves the equa- tions for interaction of light with matter. This allows completely accurate results over a large size range. Requirements for using Mie The Mie theory assumes the particle is spherical, as opposed to Fraunhofer which is a projected area prediction. The penalty for this complete accuracy is that the refractive indices for the material and medium must be known and the absorption part of the refractive index must be known or estimated. However, for the majority of users this will present no problems as these values either will be known or can be measured. A standard set of particles is available for selection in the SOP (presented in the first Analysis dialogue). More can be defined by a user, but the following parameters must be specified accurately: � Refractive Index (Real) – describes the amount of scattering that takes place as a result of light interacting with the particle. � Refractive Index (Imaginary) – the imaginary or complex refractive index. This describes the amount of absorption that takes place as the light enters the particle. � Density – the density in g/cm3. This is used to calculate the Specific Surface Area (SSA). Users who want to include the SSA as a derived parameter must complete this field. The residual shown in the Measurement Parameters view indicates how well the calculated data fitted the measurement data. Refractive index of medium This value is needed by both the Fraunhofer approximation and the Mie theory.

covers: � Records and files. � Searching and sorting records. � Exporting results – how to export information to other applications. � Extracting an SOP.

Page 7-2 MAN 0384 7 Records and files The fundamental unit of storage is the “record”. A record contains all the informa- tion for an individual measurement, including the original measurement data and all parameters that have been set to calculate the size distribution. All records are stored in a measurement file which may contain one or more records. As a practical demonstration, consider a cement manufacturer who is asked to measure a sample from the production line every hour for five hours. They may wish to save the measurement data in a measurement file called Cement.mea (measurement files always have the extension .mea). When they make the first measurement they can save the result as a record (possibly called “Hour1”) in the Cement.Mea measurement file. Once all measurements are completed the user will have a measurement file with the following structure: Cement.Mea Hour 1 Hour 2 Hour 3 Hour 4 Hour 5 Alternatively they could have created five measurement files that each contain one record. A record can be deleted but it can never be altered. However, a record can be re-analysed and the resultant record saved under a new record name. For example, imagine a user who has a record called Record1 and has found out that the refractive index they set for the dispersant is incorrect. They can select Record1, edit the parameters and re-analyse the result. A new record will be cre- ated (Record2) that is based on Record1. Record1 will still exist unaltered. To re-analyse a record: 1. Select the record to re-analyse. 2. Select Edit-Result (or right-click and select Edit result). 3. A dialogue appears allowing changes to the parameters. 4. Make the changes and select OK.

Chapter 7 Mastersizer 2000 Page 7-3 Searching and sorting records The software has powerful search capabilities that allow users to find records within measurement files that match a search criterion. Records in a measurement file can also be sorted into alphanumeric order by selecting a field header in the Records tab. Searching records Users can search many measurement files to find records matching a set of search criteria they define. Any parameter contained in the file can be a search clue. For example, it is possible to search all measurement files for records measured after a certain date that contain a D(v, 0.5) value of more that 50 microns. To search measurement files: 1. Select Tools-Find measurements to open this dialogue: 2. Use the Files tab to specify which measurement files to search. Use the Browse button to select a directory which contains the measurement files (enabling the Search subfolders check box extends the search to all sub- directories of this directory). In the Named box specify the name of the measurement files to be searched. By default this is set to *.mea, which will search for all measurement files in the selected directory. Wild cards can be used to narrow down the search. For example selecting “Titanium*.mea” will search for all measurement files beginning with “Titanium”. 3. Select the Parameters tab to specify the search criteria.

Page 7-4 MAN 0384 ill 7756 The main list box  displays all the search criteria that have been set (when starting a new search this will be blank). To add search criteria to the list, select the Add button. More than one criterion can be specified. When the search is initiated all records that match all search criteria are displayed. 4. Selecting the Add button displays this dialogue: The Parameter list box lists all parameters available in the measurement file. Select one and use the Condition and Value list boxes to set the conditions of the search. Select OK to add the search criterion to the list box in the previous dialogue. A single search criterion can be altered or deleted by selecting the Edit and Delete buttons in the Find Measurements dialogue. 5. Start the search by pressing the Find button. Once the search is completed, all records found will be displayed in a window similar to the normal Records tab, except that all the headers for the fields of the records will change to reflect the parameters set in the search criteria. Note If a large number of records are found in the search, it may take some time to display the search results as all measurement files must first be loaded. 1 i

Chapter 7 Mastersizer 2000 Page 7-5 The results of the search combination can be saved. Saving consolidates all the records found into a single measurement file, effectively making a copy of each record from its original measurement file. Reusing search criteria The search criteria can also be saved so that they can be opened and used at a later date. This is governed by these search buttons: � New search - clears all criteria currently set. � Open search - opens a previously saved search. � Save search - saves the current search criteria to a new file. Sorting records Records in a measurement file can be sorted into alphanumeric order. From a measurement file window select the Records tab. Selecting any of the field headers will rearrange all records into alpha-numeric order based on that field. For exam- ple, selecting the Measured on header lists all records into numeric Measured on date order.

Page 7-6 MAN 0384 Exporting results There are several ways to export information from the Malvern application to other applications. These are: � One or more records can be selected in the Results tab and “Dragged and dropped” directly into another application (provided that the application sup- ports tab separated formats e.g. Excel). � A table or graph can be dragged and dropped into another application by select- ing the item, then dragging while holding the Ctrl key. � A table or graph can also be copied by selecting the item then selecting Edit- Copy Table or Edit-Copy Graph. The item can then be pasted into another application. � Any of the parameters from one or more records can be exported as a text file. This file can then be loaded into a word processor or spreadsheet. A template is used to specify which parameters are exported. Use the Configure-Data export templates command to create and modify templates. � A measurement file can be attached to an email. Use the command File-Send, which opens the computer’s default mail program, and attach the file. Exporting results To export a record: 1. Select one or more records from a measurement file. 2. Select File-Export data. This dialogue will appear: 3. Select a template from the Export data using this Template list box.

Chapter 7 Mastersizer 2000 Page 7-7 4. Use the Format Options section to specify the separator character used between fields. Different spreadsheet packages require different field separa- tion characters to correctly parse the data output. Commas are the most usual but these should not be used if they are numerical separators in the country where the instrument is to be used. (e.g. France). The data can be exported to a file or directly to the clipboard by selecting the appropriate radio button. To use a file, Browse for it. An alternative way to export data is to select one or more records and simply drag the records to another application and then drop them onto a page. This method uses the template specified in the Default Template list box in the Data Export Templates dialogue. This dialogue can be accessed by selecting Configure-Data export templates. Creating an export template New export templates can be created (or existing ones modified) by selecting Con- figure-Data export templates to open this dialogue: Selecting New Template adds a new template name in the Available Templates list and then gives the user the option of changing the template’s name. (The tem- plate name can be changed later by pressing the Rename button.)

Page 7-8 MAN 0384 Having created it, set the template’s parameters by pressing the Edit.. button to open this dialogue: The Parameters list box displays all parameters available in a measurement record. The Selected list box displays all parameters that are to be included in the tem- plate. Add or remove parameters from this list by using the Add and Remove but- tons. To change the order in which the parameters are displayed in the Selected list, select a parameter then press the Move up or Move Down buttons as appropriate. A standard template Result Analysis(M) is supplied that exports all fields of the standard report page Result Analysis(M). Extracting an SOP The SOP settings used to produce a measurement can be extracted for reuse. To extract an SOP: 1. Select a record in the measurement file. 2. Either right-click on the record and select Extract in the menu this displays, or select Edit-Extract SOP. 3. The Extracted SOP editor dialogue opens, showing the SOP or manual measurement parameters used to make the original measurement. 4. Make any required changes to the settings and then click OK. 5. Specify the SOP file to save the changes to as a new SOP.

the problems encountered when measuring a sample are caused by bad sample preparation. If the sample is sticking together, dissolving or floating on the surface, or if it is not a representative sample, the result will be incorrect. There are many techniques available to ensure that the sample is prepared success- fully. Once a suitable dispersion technique is found for the sample, standardise the procedure (using an SOP) so that comparisons can be made between samples. This chapter gives information on: � Sample preparation flow chart – summarises the process. � Representative sampling. � Considerations for dry samples. � Considerations for wet samples. � Symptoms of poor sample preparation.

This flow diagram shows the route taken to prepare an unknown sample: ill 7825 Using liquid-borne particle suspensions, such as latex and emulsions, is usually straight forward. Use the suspension phase as the dispersant, mix the sample well and add directly to the Mastersizer beaker. Ultrasound is not usually necessary and will almost certainly affect the size of liquid particles. SAMPLE Analyse Analyse Take Representative Sample (mix well or riffle if dry powder) Analyse Ultrasound if necessary Try Surfactant Ultrasound if necessary Ultrasound if necessary e.g. Ethanol Propan-2-ol (IPA) Methanol Acetone Butanone (Methyl Ethyl Ketone) Hexane Toluene Dimethyl Digol Try Solvent Does it disperse in water? Does it float? Does Ultrasound work? Does this disperse it? Analyse Yes No No No No Yes Yes Yes

is representative of the whole sample. This section gives guidelines. If the sample is taken from a bottle or container, take care to ensure that it is thor- oughly mixed. When the sample is a powder, large particles tend to rise to the top of the container as smaller ones work their way to the bottom. In most samples there are some large and some small particles, but the majority fall between these extremes. If a sample is taken from the top of the container, mainly large particles will be measured. If this is compared to a measurement with the sample taken from the centre of the container the results will differ noticeably. If the sample is stored in a container this should be mixed thoroughly before meas- urement. Do not shake the container as this often increases the separation of the particles. Instead, hold the container in both hands and gently roll the container, continually changing its orientation for about 20 seconds. This method works bet- ter if the container is only half full. Spinning rifflers If the distribution of particles within a sample is particularly broad, representative sampling can be difficult. If problems continue, using a spinning riffler may help. This is a vibrating hopper which vibrates the sample down a chute. The act of vibrating the sample causes the larger particles to separate out and travel down the chute first. At the end of the chute a set of rotating pans collects the sam- ple evenly. When all of the sample has passed down the chute each collecting pan will contain a representative sample. Liquid samples Liquid samples can also separate out if stored in containers, with larger particles sinking to the bottom. Again, it’s necessary to mix the sample thoroughly to get a representative sample. Sample splitters/rifflers are also available for liquid samples. Beware of using a magnetic stirrer to mix a liquid sample. Large particles tend to move to the outside of the container due to centrifugal separation, and this can lead to sample biasing.

The first step when analysing a sample for the first time is to decide whether to ana- lyse the sample in a wet or dry state. This is usually determined by the nature of the end use of the sample. If the product is to be used and stored in a dry form, a dry analysis may be preferred. Some samples can only be measured in a dry state as they react with all wet disper- sants, for example they may dissolve or the particles may swell when in contact with a liquid. Another consideration is whether the material in its dry state is free flowing. Good pouring characteristics indicate a non-cohesive powder which will usually disperse well in a dry powder feeder without any difficulties, whereas a highly cohesive material tends to stick and clump together, giving biased measurements. Sample clumping together can often be overcome by drying the sample in an oven. Obviously care should be taken with delicate materials where drying in the oven may damage the sample. To drive the moisture from the sample, set the oven to the highest temperature possible, but not above its melting point! If it is obvious that using an oven is going to damage the sample, use a desiccator. A fresh sample that has not had time to absorb moisture from the atmosphere is always preferable and usually gives better results. If hygroscopic samples need to be conveyed to the system over some distances, they should be sealed into tubes as soon as possible with a silica gel bag if this is practicable. Note Application Notes describing how to develop a method for dry sample analysis are available at www.Malvern.com. i