Getting Started
Getting Started
M A N 0 1 0 1 I s s u e 1 . 3 A u g u s t 1 9 9 7Malvern Instruments makes every effort to ensure that this document is correct. However, due to Malvern Instruments policy of continual product development we are unable to guarantee the accuracy of this, or any other document after the date of publication. We therefore disclaim all liability for any changes, errors or omissions after the date of publication.
No reproduction or transmission of any part of this publication is allowed without the express written permission of Malvern Instruments Ltd.
Head office:
Malvern Instruments Ltd. Spring Lane South, Malvern.
Worcestershire. WR14 1XZ U.K.
Tel + [44] (0) 1684-892456 Fax + [44] (0) 1684-892789
Windows is a registered trademark of Microsoft Corporation.
Contents
Chapter 1 - Introduction to this manual
Welcome 1-1
Systems covered by this manual 1-1
Access to the instrument 1-2
Assumed information 1-3
Windows terms 1-3
Menu commands 1-5
Where to find information 1-5
Other reading 1-7
Chapter 2 - Getting to know your system
Introduction 2-1
A typical system 2-1
The optical unit 2-2
The transmitter 2-2
The sample area 2-4
The receiver 2-7
Differences between the long and standard bench Mastersizers 2-9
The Malvern software 2-10
The Mastersizer program group 2-10
Finding your way around the screen 2-11
Modes of operation 2-15
Menu mode 2-15
Easy mode 2-15
Program mode 2-16
On-line help 2-16
The F1 Function key 2-17
The Help menu 2-17
The Help window 2-17
Jumps and Popups 2-18
Status line 2-19
Reporting Problems 2-19
Chapter 3 - How the Mastersizer works
Introduction 3-1
What does the Mastersizer do? 3-1
How does the Mastersizer do it? 3-2
How to make a measurement 3-4
How to analyse the measurement data 3-6
The analysis model 3-6
The presentation 3-6
Calculating the result 3-7
Viewing the result 3-8
Saving the result 3-8
Chapter 4 - Making a measurement
Introduction 4-1
General measurement advice 4-1
Sample preparation 4-2
Cleanliness of the optical system 4-2
Choosing a range lens 4-3
Size range of your sample 4-3
Sample dispersion method 4-5
Avoiding lens cut off (Vignetting) 4-5
Always measure a background 4-6
Making a measurement 4-6
Instrument preparation 4-6
Document the measurement 4-8
An introduction to the measure windows 4-8
Align the system 4-10
Take a background measurement 4-11
Add the sample 4-11
Measure the sample 4-13
Chapter 5 - Analysing the measurement data
Introduction 5-1
Choosing the correct analysis mode 5-1
Choosing the correct presentation 5-3
The Malvern presentation grid 5-3
Methods of selecting a presentation 5-5
When is the presentation important? 5-6
Selecting a presentation 5-7
Special Presentations 5-8
Calculating the result 5-8
Chapter 6 - Viewing and printing the results
Introduction 6-1
Views 6-1
Reports 6-3
Overview of the standard views and reports 6-4
Understanding printing 6-6
The Graph fonts 6-7
The Table fonts 6-7
Installing and selecting a printer 6-8
Changing print settings 6-9
Printing from the Mastersizer 6-9
Chapter 7 - Interpreting the results
Introduction 7-1
Fundamental concepts 7-1
Results are volume based 7-1
Equivalent spheres 7-2
Derived distribution parameters 7-3
Understanding the tables and graphs 7-4
Chapter 8 - Automating the process
Introduction 8-1
Setting up a sequence 8-1
Chapter 9 - Sample preparation
Introduction 9-1
Representative sampling 9-1
Considerations for dry samples 9-2
Considerations for wet samples 9-3
Choice and preparation of the dispersant 9-3
Surfactants and admixtures 9-5
Surfactants 9-5
Admixtures 9-6
Slurries 9-6
Samples with unstable concentrations 9-7
Bubbles 9-7
Summary of sample preparation 9-8
Chapter 10 - Advanced result processing
Modifying results 10-1
Killing channels 10-1
Killing data channels 10-1
Killing result channels 10-3
Using the Kill cursors 10-4
Shape correction - Changing the size calibration 10-4
Extending the result 10-6
Transforming result type 10-7
Blending results 10-8
Multiple modifications 10-9
Tromp curve analysis 10-9
Chapter 11 - Maintenance
Introduction 11-1
Replacing the sample tubing 11-1
Replacing fuses 11-2
Cleaning the covers 11-3
Cleaning the optics 11-4
Cleaning the cell windows 11-4
Cleaning the range lenses 11-6
Cleaning the beam expander 11-7
Appendix A - Specification
Particle sizing specification A-1
Optical unit specification A-2
Computer requirements (minimum) A-4
Mastersizer programme specification A-5
Software Revision Level A-6
Appendix B - Chemical compatibility
Introduction B-1
Components in contact with sample and dispersant B-1
Wet sample measurements B-1
Dry sample measurements B-1
Spray measurements B-2
Appendix C - Remote interlock
Remote interlock C-1
Appendix D - Estimating the absorption
Introduction D-1
Estimating the absorption using concentration measurements D-1
Appendix E - Advice for continuous sprays
Introduction E-1
Arrange for the spray to be extracted E-1
Use the correct optical configuration E-1
Positioning the spray nozzle E-1
Don’t spray the optical unit E-2
Appendix F - Malvern addresses
Malvern subsidiaries F-1
Appendix G - EMC performance
Statement of EMC performance G-1
Statement of EMC performance for the Mastersizer S G-1
Equipment under test G-1
Test conditions G-1
EMC performance G-2
Statement of EMC performance for the Mastersizer X G-3
Equipment under test G-3
Test conditions G-3
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Welcome
Welcome to the Malvern Mastersizer “Getting started” manual. By now you should have installed your system by following the instructions in the installation manual.
This manual is designed to give a brief overview of what the Mastersizer can do and how to do it. Obviously, all the features of the Malvern Mastersizer can not be given within this manual. More detailed information is given in other manuals, such as the Software Reference manual. After reading this Getting Started manual you will be able to; identify the main features of the system, understand the basic measurement technique, perform a simple measurement and analyse the data. If you have never operated a Malvern Mastersizer before it is recommended that you read this manual fully before you start your first measurement.
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Warning
Systems covered by this manual
Mastersizer is a generic name given to a family of systems. Each system within the family uses the same principles of operation and only vary in operation in small areas. For this reason this manual has been written to cover more than one instrument.
This manual covers the operation of the long and standard bench versions of the Mastersizer X and the Mastersizer S i.e.
Instrument.
Ref. Number.
Mastersizer X standard bench. MAM 5000 Mastersizer X long bench. MAM 5002 Mastersizer S standard bench. MAM 5004 Mastersizer S long bench. MAM 5005
The Mastersizer or the samples to be measured may be dangerous if misused. Youmustread the Health and safety booklet before operating the system.
Access to the instrument
Within this manual reference is made to the various people that 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 authorized to perform all service procedures that may require the removal of the transmitter and receiver covers.
Supervisor
The supervisor is the person responsible for the management/safety of the instrument and of its operation. The supervisor is responsible for the training of the operators. The supervisor can perform all user maintenance routines identified in chapter 11, including changing the fuses.
The supervisor must on no circumstances remove the covers of the transmitter or receiver and should only remove the sample area cover when using the Mastersizer for spray measurements.
Operator
An operator is a person trained in the use of the instrument. The operator can perform all user maintenance routines identified in chapter 11 except for changing the fuses.
The operator must on no circumstances remove the covers of the
transmitter or receiver and should only remove the sample area cover when using the Mastersizer for spray measurements.
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Warning
Failure to follow these guidelines could result in the emission of laser radiation. Laser radiation can be harmful to the body and can cause permanent eye damage.
Assumed information
For clarity this manual will assume that you have a standard bench Mastersizer S. If there are any operational procedures that differ for the long bench Mastersizer S or the Mastersizer X then alternative information will be given.
Most samples measured on the Mastersizer are those dispersed in a liquid. For this reason all references to a sample preparation accessory within this manual will refer to the Automated Sample Dispersion Unit. If you are using any other accessory then consult its manual for details of operation, installation etc. Within this manual it will be assumed that the “flow cell” is to be used. Again, if this is not the case for your particular installation consult the accessory manuals for details on installation and use of the cell you do have.
Within this manual the Mastersizer system will be referred to as the “Mastersizer” or the “system” unless the information given is for a particular instrument.
Windows terms
It is important that you understand some Windows terms before reading further. (Note that US spelling is used for some terms for compatibility)
Program- The Mastersizersoftware- it can also mean the Mastersizer Basic program used within the main Mastersizer software.
Cursor or Pointer- The graphic - usually a pointer that is moved on the screen by operation of the mouse.
Icon- The graphic on the desktop that represents aprogram.
Click- The mouse button is depressed and released. If this is not qualified with a button description then assume it is the left button. ‘Clicking a button’ means click the left mouse button when the cursor is over the button.
Double-click- Press and release the mouse button twice in quick succession. If this is not qualified with a button description then assume it is the left button. Use the Mouse icon in theControl Panelof Program Manager to change the double-click speed.
Dialogue Box- A window containingcontrols. TheOKbutton accepts changes in the dialogue box. TheCancelbutton closes the dialogue without accepting the changes.
Control- This can mean a graphic on adialoguelike abutton,listbox,
PressorSelect- This means click the mouse over a control or use the
accelerator key (the underlined letter) or use theTabkey to move the focus to a
controlthen use theEnter key. Menu items can be selected using the cursor keys in the same way.
Button- This acts like a real-life button.Clickto carry out an action. A typical button is shown below.
Option ButtonorRadio Button- A series of buttons in a group, selecting one button cancels the others in the group. A radio button is shown below.
Check Box- A button that can be toggled on and off. A check box is show below.
Text BoxorEdit Box- A box you can type text or values into. A text box is shown below.
List Box- A box containing a list of options. SomeList Boxesallow multiple entries to be selected.
Combination List BoxorCombo Box- A combination of alist boxwith a
text box. A button beside thetext boxdisplays or hides the list part of the control. In some cases you can type new values into thetext boxpart, in others thetext boxjust shows the current selection from the list.
Drag- An action with the mouse which involves moving the mouse while holding down the left mouse button. This is used for movingiconsor making multiple selections in alist box.
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Menu commands
Menu commands from the Malvern software are referred to in the formmain menu-menu item. As an example, the commandFile-Save Samplerefers to selecting theSave Sampleitem in theFilemenu. The same rules apply for sub-menus of sub-menus, so thatEdit-Copy-Datarefers to theDataitem in theCopysub-menu, which itself is a sub-menu of theEditmenu. Menu commands are always shown in bold text.
Where to find information
As stated above this manual is designed to give a brief overview of what the Mastersizer can do and how to do it. In other words it is a quick guide that allows you to understand how the Mastersizer gets a result and runs you through a simple measurement procedure, hopefully steering you around the main pitfalls and directing you to more information if needed.
If you have used a Malvern particle analyser before you may wish to go straight to chapters 4 and 5 where you can find practical information on making a
measurement and analysing the data. However, it is recommended that you read this manual fully before you start a measurement.
On-line help can be gained at any point when using the Malvern software. See chapter 2 for more details.
The following is a list of the contents and objectives of the chapters within this manual.
Chapter 2 - Features of the Mastersizer system.
This chapter is designed to enable you to identify the physical features of the system and is divided into two parts.
The first part identifies the features of the optical unit, for example the function of the connectors on the end panels or the purpose of the lenses etc. The second section does the same for the Malvern software, identifying the key areas of the screen.
Chapter 3 - How the Mastersizer works.
After reading chapter 3 you will have a basic idea of the operating procedures of the Mastersizer and in particular be able to:
. Know the basic operating principles.
. Know the simple steps involved in making a measurement and analysing the data.
Chapter 4 - Making a measurement.
Chapter 4 will guide you through the practical steps needed to make a measurement to obtain the raw data.
Chapter 5 - Analysing the measurement data.
This chapter will show you how to take the raw measurement data and analyse it, using the Malvern software, to get a final result. Advice is given on the choice of optical model and the presentation.
Chapter 6 - Viewing the results.
The Mastersizer software has several standard viewing formats that allow you to display and print the results in different ways. This chapter explains the standard views and how to print them.
Chapter 7 - Interpreting the results.
This chapter gives some essential advice on understanding the results given by the software.
Chapter 8 - Automating the procedure.
This chapter gives a brief overview of the procedures involved in measuring and analysing a sample by setting up a semi-automatic sequence.
Chapter 9 - Sample preparation.
Sample preparation is one of the most important stages in making a measurement on the Mastersizer. This chapter gives additional advice to that covered in the chapter 4.
Chapter 10 - Advanced result processing.
The Mastersizer software gives the option to perform some advanced result manipulation. This chapter gives an overview on some of the options.
Chapter 11 - Routine maintenance.
The Mastersizer has no user serviceable parts but there are certain maintenance routines that can be carried out by the user. These include cleaning the optics etc. This chapter gives advice on these routines.
Appendices.
At the rear of the manual is a series of appendices that cover some of the technical aspects of the Mastersizer, including the technical specification.
Other reading
More detail on the subjects within this manual can be found in the following manuals:
Title
Ref. number
The Malvern Software reference manual. MAN 0102 The Malvern BASIC reference manual. MAN 0103
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Getting to know your system
Getting to know your system
Introduction
By now you should have connected up the system by following the instructions within the system and accessory installation guides.
Spend some time to familiarise yourself with all the physical features of the system by reading the following sections. It is probable that you will not use all of the features described as some are used for specific accessories or applications only. This chapter is only intended to give you a guide to identify the features. A description of how the system actually works and how to use it will follow in the next few chapters.
This chapter is divided into three sections. Section one will identify the main modules of a typical system. Section two will examine the features of the optical unit in more detail. Finally the third section will identify the main features of the Malvern software in more detail. Information on the sample preparation
accessories can be found in their own manuals.
A typical system
The diagram below shows a typical system with its key features of the optical unit À, one or more sample preparation accessoriesÁand a computer systemÂ.
Theoptical unitis used to collect the raw data that is used to measure the size of a sample.
The sole purpose of thesample preparation accessoryis to prepare the sample and then deliver it to the optical unit so that it can be measured. Malvern makes
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many sample preparation accessories to handle all forms of sample, including dry powders, aerosols and samples dispersed in a liquid. You may have many sample handling accessories or none at all depending on your particular requirements. Consult the individual accessory manuals to identify the features of the sample preparation accessories.
Thecomputer systemis a stand alone computer that runs theMalvern software. It is the Malvern software that analyses the raw data from the optical unit to give the size of the particles. Once completed the result can be further analysed or reports printed etc.
The following section gives a more detailed overview of the features of the optical unit.
The optical unit
The optical unit consists of three components; the transmitterÀ, the receiverÁ and the sample areaÂ. Each of these components are identified in the diagram below.
The purpose of the optical unit is to collect the information from the scattered light when a laser is passed through the sample to be measured.
The transmitter
The transmitter contains the laser and electronics that produces the laser beam that is used in the measurement of the sample.
The main features of the transmitter are on the transmitter end panel. Use the figure below to identify these features and their function.
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“LV out” connector
Connector that carries the low voltage power supply to the receiver.
Á
Power input socket
Main power input socket to the optical unit.
Â
Fuse holder
Fuse for the optical unit. Read the health and safety manual before attempting to change the fuse.
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“Interlock” connector
Laser interlock connector that shuts off the laser if any of the optical unit safety interlocks are defeated. This connector must be connected to allow the system to work.
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“Remote” connector
Connection for an external laser interlock that turns the laser off when the interlock is defeated. The usual form of this interlock is a switch on the door to the room in which the system is installed that switches the laser off if the door is opened. See appendix C for details.
If a remote interlock is not used then a shorting plug is connected to allow the laser to be powered. The system will not work without a shorting plug or a remote interlock connection.
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Laser power key
The laser has to be turned on by turning the laser power key. This is an additional safety feature, allowing the key to be removed to stop unauthorised use of the system.
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Laser power indicator
A visual indicator to warn the operator that the laser has been powered up by turning the laser power key.
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Optical unit power switch
The main on/off power switch for the optical unit.
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The QSpec logo
If your company operates within the pharmaceutical industry, you will be pleased to know that the Qspec sticker means that the instrument is eligible for coverage by a Malvern QSpec Validation contract which can help you to meet the
requirements of the Food and Drug Administration (FDA). For further details contact your local Malvern Distributor.
The sample area
The area between the transmitter and receiver is the sample area. This is where the sample to be measured is passed through the laser.
Use the diagram below to identify the main features of the sample area.
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À
Sample area cover
Protective cover over the sample area. Designed to protect the operator from laser radiation and to keep the amount of background light to a minimum during a measurement.
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Warning!
Unless you are performing spray measurements do not attempt to remove the sample area cover.
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Beam expander
The beam expander is used to increase the diameter of the laser beam. Once the laser beam has been expanded it is known as the analyser beam.
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N o t e . The beam expander is actually part of the transmitter optics but has been included here for clarity.Â
Range lens
The purpose of the range lens is to collect the laser light that has been scattered from the sample and focus it onto the detector electronics.
Both the Mastersizer X and Mastersizer S have a number of range lenses available, with each lens covering a different size range of particles. A list of lenses available and their corresponding size range is given below.
Mastersizer X
Mastersizer S
Lens Size range Lens Size range
45mm 0.1 - 80µm 300RF 0.05 - 880µm
100mm 0.5 - 180µm 300mm 0.5 - 880µm
300mm 1.2 - 600µm 1000mm* 4.2 - 3480µm
1000mm* 4.2 - 2000µm
* The 1000mm range lens are available on long bench versions only.
The sample area coremoved for spray measurements. Read the safety manual before removing the sample area cover.
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Caution!
See “Choosing a range lens” in chapter 4.
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Sample cell
The sample to be measured is passed through the analyser beam by propelling the sample through a cell. Malvern make various forms of cell to cope with different types of material. One exception to using a cell is the case of spray measurements where an aerosol is sprayed directly though the analyser beam.
There are three types of cell available:
Stirred cell.This is the simplest form of cell and is designed for samples dispersed in a liquid. The sample and its liquid dispersant are placed into the cell and the solution is kept in suspension by magnetically rotating a stirrer bead within the cell.
Flow cell.A flow cell is also used for samples dispersed in a liquid. The sample and dispersant are kept in suspension by an external accessory that then pumps the solution through the flow cell.
Air cell.An air cell is used when measuring dry powders. The sample is blown or dropped through the air cell by an external accessory.
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Cell pipe connectors
If a flow cell is used then the connecting pipes from the cell to the sample preparation accessory are passed through the covers via the pipe connectors.
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Removable accessory panels
Certain accessories, e.g. the Free Fall Dry Powder Feeder or the air cells, protrude outside the sample area cover. To facilitate this there are three removable
accessory panels where one or more are removed to fit the accessory. The optical unit will not operate correctly if more than one range lens is mounted at any one time.
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Back scatter connector
Mastersizer S only.The 300RF range lens has a back scatter detector which is connected to the back scatter connector on the receiver bulkhead. No other lens uses the back scatter connector.
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Laser interlock connector
On the rear of the sample area cover is the laser interlock connector. This connection must be made if the laser is to work.
The long bench versions of the Mastersizer have two interlock connections - one on the rear of each sample area cover.
The receiver
The final part of the optical unit is the receiver unit. The receiver collects and stores the information received from the scattering of the analyser beam as it passes through the sample. Once the data has been collected it is sent to the computer system for analysis.
The main component of the receiver is the detector (sometimes called the diode). The detector is actually made up of a number of photo-diode elements that are arranged in a radial pattern. The detector is not visible in normal use.
Always replace the accessory panels after the accessory has been removed. Never run the system with the panels and accessory removed.
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Caution:
The main features of the receiver unit are on the receiver end panel. Use the figure below to identify the features on the receiver end panel and their function.
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“Computer Comms” connector
Communication cable that is connected to the computer. Data from the receiver and control commands from the computer are transmitted down this cable.
The detector is the most delicate (and expensive) component of the system. In normal use the detector is safely contained within the covers of the receiver unit. However, the Mastersizer X moves the detector within the covers. If the diode was in the position required for the 45mm range lens then the detector can be touched if the range lens was removed. On no circumstances touch or clean the detector.
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“Aux. Comms” connector
Auxiliary communications connector. Some sample preparation accessories (e.g. Automated Sample Dispersion unit) are capable of controlling the optical unit. When this is the case they are connected to this connector.
Â
“L.V. In” connector
Connector that carries the low voltage power supply into the receiver.
FeaturesÃtoÆare usually used when performing spray measurements.
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“Digital I/O” connector
The digital I/O connector is a general purpose user programmable I/O port. A particular use for the port is to connect the spray synchroniser accessory.
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“Sweep trigger” connector
The sweep trigger is used to start a measurement “sweep” when using the spray accessories.
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“Exp. trigger” connector
The “Exp. trigger” is the “experiment trigger”. The experiment trigger is used to start an experiment when using the spray accessories.
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“Abort” connector
The abort connector is used to stop the experiment triggered using the “Exp. trigger” above.
Differences between the long and
standard bench Mastersizers
The long bench Mastersizer is able to measure a larger range of particle sizes. To do this the long bench version has an extra sample area cover and an extra lens (the 1000mm lens). When the 1000mm lens is used it is mounted in the additional sample area. All other functions and features are the same as the standard bench.
The Malvern software
The Malvern software controls all the functions of the optical unit during a measurement and then uses the data collected to calculate the result.
The software is Windows based, requiring version 3.1 or greater and has been designed to follow the guidelines laid down by Microsoft regarding the way in which the software is operated and how it co-operates with other Windows programs. Remember that, although the software is often operated using the mouse, all of the measurement functions are accessible by using the keyboard alone.
If you are unfamiliar with using the Microsoft Windows environment you should read the Microsoft Windows manual. Running the Microsoft Windows tutorial will allow you to practice your mouse skills.
The Mastersizer program group
When the Mastersizer software is installed the Mastersizer program group shown below will appear in the Program Manager window.
There are three program icons within the program group. The first is the main Mastersizer program icon. To enable the Mastersizer software, double click on this icon.
The second icon is the presentation generator program. This is a program that is usually run from the Mastersizer software but can be run independently by double clicking this icon. The presentation generator calculates new “presentations” that are used in the analysis of the measurement data. Presentations are discussed in detail later in this manual.
The final icon is the Bitmap Editor. This program allows you to create your own icon bitmaps.
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Finding your way around the screen
Before we explain how the software works you should familiarise yourself with some of the key features of the screen by using the diagram below.
The main features are:
À
Title bar (or Caption)
This shows the name of the program (Malvern Mastersizer) and, among other things, tells you the name of the current sample file.
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Menu bar
The menu bar contains the main menu headings for all Mastersizer functions. There are several ways to select an item from the menu bar:
Using the mouse.
To select an item from the menu bar use the left mouse button to click once on the menu item. The menu list will drop down. You can then select the item from the menu list by clicking once on the item.
Using the keyboard.
To select an item from the menu bar using the keyboard, hold down the
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Altkey and press the letter which is underlined in the item required. For example to use theMeasuremenu hold downAltand pressm. Whenever you use a key in this way it does not matter if you use upper or lower case.
Mormwould both work.
Again a menu list will drop down. To select an item from the list type the letter that is underlined. For example, typingdwill select theDocument...
item to enter sample details.
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 you can pressCtrlandNtogether to selectMeasure-Document...without having to use the main menu and drop down menu.
The items which end with a row of dots (...) will cause dialogue boxes to appear. Those with no dots will cause an immediate action. For exampleDocument...
displays a dialogue for you to enter details butCleanwould cause the sample handling unit to begin a cleaning sequence without any further action. Some items are shown in grey. This indicates that the choice is not currently available. For example, theCleanitem may be grey because no sample handling unit is installed and theBackground, InspectandSampleitems may be grey because these operations may not be performed until the system has been aligned.
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Button Bar
The Easy button bar (or toolbar) contains a selection of buttons which you can use to perform the most popular operations. Each button will have its equivalent commands within the menu bar. For example using the calculate button is equivalent to using theCalculate result...menu item from theMeasuremenu. A button may represent more than one command, for example pressing the setup button will automatically run you through the threeSetupmenu items;
Setup-Hardware,Setup-AnalysisandSetup-Presentation.
The default button bar set when the Mastersizer software is first installed is:
Calculate Button
Setup Button
A - Setup B - Open Sample File C - Document D - Align Optics E - Measure Background F - Inspect Result G - Calculate Result H - Save Record I - Print J - Setup Sequence K - Start Sequence L - Clear Graph M - Graph Scale Up N - Graph Scale Down O - Exit Mastersizer
To help you identify a menu button a short description of the action of the button is displayed in the status bar when the cursor is moved over the buttons - (The cursor also changes to a picture of a hand when over a button).
As with the menu bar, if a button is not available it will be shown in a lighter colourÀto show it is disabled. i.e.:
The keyboard can be used to select Easy buttons by using the key combinations which appears underneath each button. Because space is limited some of the text has been abbreviated, for example “A+S+1” means hold down the Alt and Shift key while typing 1.
It is possible to customise the button menu to suit your own needs. See
Control-Easy Buttonsin the software reference manual to change the layout of the buttons and the pictures that are used. You can also hide the key description which appears below the buttons.
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Table pane
The table pane is used to show the result information in tabular form. Other information relevant to the measurement will also be shown. The type of
information displayed in the table pane is determined by the “view”. The software has a list of standard views that can be easily changed by the user. Custom views can be created by the advanced user.
To select a view, either select theViewmenu item or move the mouse cursor to any part of the table pane and press the right mouse button. This action will display a pop-up menu which shows you the selection of views available. Once selected the table and graph pages will immediately update. See chapter 6 for details of the views available.
Double-clicking the left mouse button in the table pane has the effect of
temporarily expanding that page to fill the window. Double-click again to restore the split screen. Scroll bars appear on the table pane if the pane is too small to show the whole table.
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Graph pane
When a different view is selected the graph pane automatically changes to represent the data in the table. The graph pane always shows the same result but there are options to change the way it is displayed, for example the graph can be shown as a histogram, oversize plot, undersize plot, frequency plot or the result can be over-plotted on a graph of previous measurements.
The form of each graph may be modified by clicking the right mouse button over the graph pane (or by selecting theSetup-Graphmenu item). This produces a dialogue that allows plot styles, axes and colours to be changed. See
Setup-Graphin the software reference manual for more information.
If the left mouse button is pressed with the cursor over a graph the query cursor appears.
Moving the query cursor over the graph displays information about the graph at the co-ordinates of the cursor. A typical message would be:
x = 2.84 µm, y = 11.8% (59.1%).
This means at this point of the graph that 59.1% of the sample is below 2.84 microns and that 11.8% of the sample is in that particular size band. Double-clicking the left mouse button in the graph pane has the effect of temporarily expanding that pane to fill the window. Double-click again to restore the split screen. The graph will automatically fit the graph pane.
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Splitter bar
The splitter bar allows you to change the proportions of graph and table panes i.e. to make the graph or table pane bigger or smaller.
To move the split between graph and table panes using the mouse, move the cursor onto the splitter bar - the arrow cursor will change to a double-headed arrow. Now, hold down the left mouse button and drag the bar to the new position. Release the mouse button when the desired position is reached. The splitter bar may also be controlled from the keyboard or from the menus.
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Status bar
The status bar is split into two parts. The left hand section is used to show the status of the software. It usually shows the messageReady - Press F1 for Help. This will change to inform you when the system is loading or saving files, calculating, etc. As a menu is selected or the cursor moves over a toolbar button help information is shown.
The right hand part of the status bar shows the instrument status. The instrument status bar showsInstrument Readyif the optical unit is correctly connected and switched on andInstrument NOT READY otherwise. The instrument status bar will also show the progress of a measurement.
Modes of operation
The Malvern software has three main modes of operation, Easy, Menu and program mode, which are summarised below.
Menu mode
Menu mode is the use of the menu bar and its options to control the Mastersizer. Using the menus gives you access to all functions of the software. For full details of all the options in menus see the software reference manual.
Easy mode
The Easy button bar (or Toolbar) provides a simple way to select frequently used actions. For most samples a full analysis of a sample can be made by using the buttons. The buttons can be used by relatively inexperienced operators.
Splitter Bar Cursor
Program mode
The program mode uses the built-in program language “Malvern Basic” to allow you to build complex measurement sequences with prompts to enter values, perform actions, etc. and detailed checking of error conditions. Such programs may be run individually, assigned to single key operations or set up to run automatically when the software starts.
The Malvern basic language is an advanced feature that is usually used by the more experienced user.
The full details of programming in the Malvern Basic language are given in the Malvern Basic manual.
The three modes above are designed so they can be used in conjunction with each other. You may find that you only need to use the easy mode buttons or just the menu items but it is possible to use all modes in a single measurement. For example you may align the system by pressing the align button from the button bar, but then follow by measuring the background by using the menu item
Measure-Background.
Always remember, as with most modern Windows programs, there is usually more that one way to operate the software. A function like printing a report for example can be done in several ways; by using theprintoption in theFilemenu, pressing the print button in the button bar or using the keyboard by pressing “F11”.
Once you have gained experience in the operation of the Mastersizer it will be normal for you to set up automatic sequences of measurements that will automatically go from one procedure to the next, pausing only for you to enter details. To do this you set up a measurement “sequence”. The software also allows manual control of each stage. Even in manual control the system will take you from one stage to the next logical stage using a single key action. The system also locks-out actions that may lead to invalid measurements and gives warnings if measurements are not within accepted limits.
Getting help
On-line help
Microsoft Windows contains a help program which can give information on using Windows itself and on programs that use Windows. As well as leafing through the manuals to find out how to do something you can also refer to the on-line Help
system. Almost all the software reference manual is available on the Help system and in some cases is easier to search than the manual.
The F1 Function key
You can get help on using the Mastersizer software at any point by pressing theF1
function key. If the main Mastersizer window is active then the Help Contents page will be shown. If a dialogue box or other Mastersizer window is active then help on using that window will appear. This ability to give help on the operation being carried out is known as ‘context-sensitive help’.
To get help on the main Mastersizer window hold down theShiftkey and press
F1. The mouse cursor then changes from the normal arrow to the Help cursor. When the Help cursor is active clicking the left mouse button over a component of the Mastersizer window will show help on that component. If a menu is selected or a button in the toolbar is clicked then help will appear on that command.
The Help menu
The far right menu in the Mastersizer menu bar is for Help. This allows you to go direct to specific parts of the Help system. The Help menu items are:
Contents- The main list of contents in the Help system.
Menu Command- The list of menu commands.
Program Language- The contents of the help on using the built-in Mastersizer Basic language (program mode).
Keyboard- How to use the keyboard for; commands, moving the splitter bar of the window and changing the scale the graph etc.
Window- The list of Mastersizer window components.
Help- This command displays the Microsoft Help information on using the Help system.
For more information on the commands in the Help menu see the software reference manual.
The Help window
The Help window is an independent window with its own menu and sizing border. If you have the Mastersizer window maximised (filling the whole screen)
you may find it useful to make the help window always stay on top of the Mastersizer window.
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To set the Help window to be always on top:
. Select theHelpmenu item from the Help window.
. If theAlways on Topitem does not have a check mark against it then click this item (or press theEnterkey with this item highlighted).
The Help window has a row of buttons below the menu for the most used actions:
Contents- Pressing this button send you to the main contents page.
Search- Selecting this displays the search dialogue - Searching Help.
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To search for the required information:
. Type the first few letters of the item to search for in the text box. The list box scrolls to show the item.
. Double-click the item in the list or pressShow Topics. The list box at the bottom of the dialogue shows one or more topics.
. Select the topic in the bottom list box. Double-click or pressGo To.
. The help window changes to the topic.
Back- Pressing this button moves you to the last help topic displayed.
History- This button displays a window showing a list of help topics visited. Double-click an item to go back to that topic.
“<<”and“>>”- These are the browse buttons - click these to see related topics to the current one.
Glossary- Shows a list of glossary items. Click these to see the descriptions.
Jumps and Popups
In the Help window you will see text which is underlined with a solid line for example Diffraction. Click this to move to another topic. This is known as a jump. Text that is underlined with a dotted line will show a popup window with extra information when it is clicked with the mouse. Click the mouse in the window to make it disappear. This is known as a popup.
When the mouse cursor moves over a jump or popup item it changes to the help jump cursor.
The cursor also changes when it moves over certain graphics and buttons. Clicking these items show more information about them.
Status line
When a menu is selected or the mouse cursor moves over a toolbar button the status line at the bottom of the Mastersizer window will show information on the command.
Reporting Problems
Before reporting a problem please check the relevant sections of the user and reference manuals, or any accessory manuals, which may have an answer. If the problem persists try to give as much detail as possible.
If there is a problem in the software try to give information that will allow the engineers at Malvern to reproduce the conditions. If the problem is in the result or the analysis the Malvern engineers will require a copy of the Data report. A list of the Malvern subsidiaries can be found in appendix F.
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To print a data report:
. Change theViewtoData.
. Select a report print in theFile - Printdialogue.
Help Jump Cursor
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3
Introduction
After reading this chapter you will have a basic idea of the operating procedures of the Mastersizer and in particular:
. Know the basic operating principles of the Mastersizer.
. Know the simple steps involved in making a measurement and analysing the data. More detail will be given in later chapters.
What does the Mastersizer do?
Scientists have for centuries tried to predict the way particles scatter and absorb light. There are many theories and models that the modern particle analyst can use.
One of the simplest theories used is the Fraunhofer model. This model can predict the scattering pattern that is created when a solid, opaque disc of a known size is passed through a laser beam.
This model is fine for a lot of particles but it does not describe the scattering exactly. Very few particles are disc shaped and a lot of particles are transparent. The 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 you know some specific information about your particle, such as its refractive index and its absorption. The key fact about these theories is that if you know the size of the particle and other details about its structure, you can accurately predict the way it will scatter light. 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? The Mastersizer works backwards from the above theories by using the Mastersizers’ optical unit to capture the actual scattering pattern from a field of particles. Then using the theories above it can predict the size of particles that created that pattern.
How does the Mastersizer do it?
There are two distinct procedures involved in measuring a sample on the Mastersizer.. Firstly there is the capturing of the scattering pattern from the sample - this is known as the “measurement”. This is the purpose of the optical unit. The detector within the optical unit is made up of many individual detectors. Each detector will collect the light scattering from a particular range of angles. A typical light scattering pattern is shown below.
Each bar in the histogram represents the light scattering from one of the detector elements.
The detector takes a “snap-shot” of the scattering pattern. Obviously this snap-shot will only capture the scattering pattern from the particles that where passing through the analyser beam at that particular time. Taking only one snap-shot may not give you a representative reading of the scattering pattern. To overcome this the Mastersizer takes many snap-shots (known as sweeps) and averages the result. Typically over 2000 sweeps are made for each measurement, with each sweep taking 2mS.
. Secondly, once the measurement is complete the raw data contained in the measurement can be analysed by the Malvern software using one of the theories above.
The measurement data is analysed by first selecting a “presentation”. A presentation is a predicted scattering pattern from theoretical particles. The software has many presentations on disc that represent particles of different materials suspended in different dispersants. You will choose the
presentation that matches the sample and dispersant you are measuring.
Detector Number 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 8 16 24 32 40
Obscuration = 10.3 % Data Background
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The presentation data is then made to fit the measurement data - this will give you the final size distribution.
Once the data has been analysed the information can be displayed in various ways. Usually the display will show you a graph of the result and a table showing the same information in a tabular form. The graph below shows four of the more common graph types for displaying the result.
The histogramÃdisplays the result in the form of “in band” percentages. i.e. 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. The histogram graph uses the left scale. Unless you change the size bands, the initial analysis uses the size bands that are set by the physical design of the detector.
The “undersize” plotÀdisplays the result in the form of “% of sample below a certain size of particle”. For example by reading the values from the graph you may be able to determine that 10% of the sample is under 23 microns etc. (the exact value can be read from the table that will accompany the graph). The undersize plot is read from the right hand scale on the graph. The undersize plot is calculated from the initial size bands by fitting a curve to the analysis data so that values within a size band may be read.
The oversize plotÁis similar to the undersize plot except that the result is in the form “% of sampleabovea certain size of particle”. For example by reading the values from the graph you may be able to determine that 90% of the sample is above 23 microns etc.
The frequency curveÂis calculated by differentiating the undersize curve. The frequency curve is particularly useful for displaying the results to show the
Particle Diameter (µ m.) Volume % 0 10 20 0 10 20 30 40 50 60 70 80 90 100 10.0 100.0 2 1 4 3 ILL 1869
“modes” or peaks in the graph. Several peaks in the graph indicate that there are distinct sizes of particles within the sample. This “at a glance” inspection of the results will be difficult if the result was shown as an undersize or oversize plot. Another use for the frequency curve is to compare results from different
measurements - over-plotting results can be done using other graph types but the graph may become confusing.
It is usual for the operator to use the software to setup a “sequence” that will automatically go through the procedures above in one go. There is a large choice of options when setting up a sequence, for example, you can easily arrange for the Mastersizer to measure a single sample many times, each time analysing the measurement data (using a pre-chosen presentation), saving the result and over-plotting each result on a graph.
Alternatively you can go through each stage individually. Before you setup a sequence it is important to understand the procedures in each stage. The following section explains these procedures
How to make a measurement
It is vitally important that the measurement is carried out correctly. It should be obvious that if you make a poor measurement then no amount of analyzing of the data can give you a good result.
A brief note on each stage of the measurement follows. The practical procedures for making the measurement is covered in chapter 4.
Setup for the measurement
The Malvern software will need to know some of the physical parameters of the system, i.e. which lens is fitted or the type of sample preparation accessory is attached.
Obviously this will only be done once and will only have to change if you alter the physical setup, by changing a lens for example.
Align the optics
If the instrument has just been switched on or any of the optics have been moved (removing and cleaning the cell for example) you will have to align the laser so that it hits the centre of the detector. This is a totally automatic procedure with the Mastersizer and only requires the pressing of a single button.
Document the measurement
It is always good practice to document your measurement so that you will be able to identify what was measured and how it was measured. A short sample identifier and notes can be saved with the measurement.
Measure the background
The scattering pattern from your sample is contaminated by light scattered by impurities within the dispersant, on the windows and lenses and also electrical “noise”. To remove this contamination a “background”
measurement is made that measures the scattering pattern with no sample in the analyser beam. This background measurement is then subtracted from the scattering pattern with the sample present to leave only the information from the particles.
Add the sample and inspect the concentration
The correct amount of sample has to be passed through the laser beam to allow a good measurement to take place. Too little sample and there will not be enough scattered light to be detected. Too much sample and the light scattered from an individual particle will itself be scattered by other particles - this is known as multiple scattering.
The Mastersizer determines the correct concentration of the sample by measuring the amount of laser light that has been lost by passing it through the sample. This is known as the “obscuration” and is given as a percentage. For example if 30% of the laser light is lost when it passes through the sample it is said to have an obscuration of 30%.
Sample is added to the system until the obscuration is within an acceptable range.
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N o t e . The preparation of the sample before it is added to the system can be critical. Over half of the problems encountered when measuring a sample are caused by bad sample preparation. If your sample is sticking together, dissolving, floating on the surface or if you have failed to get a representative sample youwill notget a correct result. Read chapter 9 for details on sample preparation.Measure the sample
Once all the steps above are completed the scattering pattern is then measured.
It is usual at this point to go on and analyse the measurement but it can be saved on the computer so that it can be analysed at a later date if you wish.
How to analyse the measurement data
There are three steps required to analyse the measurement data:
. Choose the analysis model to be used.
. Choose the presentation to be used.
. Tell the computer to calculate the result.
The analysis model
The analysis model tells the computer what the expected shape of the result graph will be. There are four choices available; polydisperse, multimodal, monomodal or very polydisperse.
Polydispersemodel does not assume anything about the shape of the result graph.
Multimodalmodel assumes that there will be one or moredistinctpeaks in the results graph - indicating that there are several distinct sizes of particles.
Themonomodalmodel assumes that there will only be one peak in the result graph - indicating that there is only one size of particle.
Very polydisperseis similar to polydisperse but is only used for one or two special circumstances. (For Mastersizer X only.) See chapter 5 for more information.
Compressed rangeanalysis has a reduced upper size limit and is meant for use with dry powder and spray measurements. (For Mastersizer S only.) The choice of which model to use is very simple - unless youdefinitely know
that the result graph will be of a particular shapealwaysuse the polydisperse model.
The presentation
As stated earlier, the Mie theory needs to know specific information about the structure of the sample and the medium it is suspended in so that it can calculate exactly how light passes through them. The specific information required is the relative refractive index of the particle to be measured, the particle adsorption
(imaginary refractive index) and the refractive index of the medium that the particle is suspended in (dispersant).
Once the Malvern software knows this information it can calculate the expected scattering pattern from these particles. This scattering pattern is known as the “presentation”. The presentation is identified by a label of the form “3OHD”. The details of how these codes are made up will be discussed later.
There are three ways of selecting a presentation.
. The easiest way is to use one of the four “default” or “system” presenta-tions. These are;
Fraunhofer (3$$D). This is the presentation that is used when you wish to use the simpler Fraunhofer model.
Standard - Wet (3OHD). This is a presentation that takes a “middle of the road” value for the refractive index and adsorption of the sample and assumes that the particle is suspended inwater.
Standard - Dry (3RHA).This presentation is the same as standard-wet except assumes that the particle is suspended inair.
Reference Reticle (3$$1).This is the presentation that is used when the Diffraction Reference Reticle accessory is used to validate the system. Obviously this will only be used if you have the accessory. Read the Diffraction Reference Reticle accessory manual for further details.
. For a more accurate choice you can enter the refractive index of the particle etc. and the software can then find thenearest matchfrom the many pre-calculated presentations stored on the computer.
. Thirdly, if you require an exact presentation you can again enter the particle details and then ask the software to generate the exact presentation.
You may ask yourself “If I can generate the exact presentation why bother with a default or near-match choice”. Firstly, generating the exact presentation takes time. Secondly, for most samples using either the standard-wet or standard-dry presentations are more than sufficient. Choosing another presentation is only required in specific circumstances, such as the majority of particles being under 10 microns in size. Details of choosing the correct presentation are given in chapter 5. Until you know more about choosing a presentation it is recommended that you use one of the two standard presentations.
Calculating the result
Once the analysis and presentation have been selected, the result is calculated by simply pressing the calculate button. The progress of the calculation of the result
is shown on the screen by the “Residual”. The residual is an indication of how closely the calculated data has been fitted to the measurement data and is
expressed as a percentage. By examining the residual you will be able to determine if the correct analysis mode or presentation has been chosen.
Viewing the result
Once the software has finished calculating the result, the graph pane and table pane of the screen are updated to show the new result, using the present settings for the displays. The result data can be shown in different forms by loading in a different “view”. There are several standard views available or you can create your own.
Details of the views available are described in chapter 6.
Saving the result
It is important to have a structured way to save all of your data so that in can be locatedeasily in the future. There are three items you need to understand to successfully file your data. These are:
. Records.
. Run number.
. Sample file.
A record contains all the data that has been collected for a particular experiment. A record will contain the measurement data, the analysis data, notes on the experiment and the run number. A record is identified by a sequential record number.
If you run a number of experiments, on the same sample for example, the run number can identify the sequence of results. The run number can either increment after analysis or after saving.
A sample file is a file that contains a collection of records. The sample file takes the form of a file name with a .SAM extension.
It is probably easier to understand these terms by following a practical example. Suppose you had to measure some samples from a production line that operated 5 days a week and 4 hours a day. Every hour you have to take 3 samples from the production line and measure these samples. One way to store these results is to have a separate sample file for each day of the week. A typical structure of the sample file for one day (Monday) is shown on the next page.
Sample file: Monday.SAM
Record Number
Run Number
1 1 2 2 3 3 4 1 5 2 6 3 7 1 8 2 9 3 10 1 11 2 12 3
As can be seen, the run number is reset after each batch of 3 samples. So, for example, to see the data for the second sample taken two hours into Monday, you will open record number 5 from the MONDAY.SAM sample file.
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4
Introduction
It is usual for the operator to use the software to setup a “sequence” that, once set up, will automatically go through the procedures of measuring the sample, analysing the data and saving the results by simply pressing a single button. However, it is important to know the individual stages that are involved. This chapter is concerned with the measurement of the sample - the next chapter will give the practical details on analysing the data.
In chapter 3 the section “How to make a measurement” gave a brief overview of the stages involved in making a measurement. These stages where:
. Setup the system.
. Document the sample.
. Align the optics.
. Measure the background.
. Add the sample.
. Measure the sample.
This chapter will explain the practical steps of each of these stages. It has been found that the best way to learn how to measure a sample is to actually make a measurement on a system. To get the most benefit from this chapter it is advised to read through the chapter first and then to go through a second time following the instructions to make a measurement on the system.
To do this you will need a suitable sample to measure and a suitable dispersant to disperse it in. Either ordinary dairy cream or a PVA glue dispersed in water are readily available samples and dispersant that should give you good predictable results.
By the end of this chapter you will have gained the practical knowledge that is needed to perform a measurement, such as which range lens to choose or how to prepare the sample etc. This knowledge will allow you to understand the procedures involved in setting up a measurement “sequence”.
General measurement advice
Before we make a measurement there is some important general advice that should always be noted.
Sample preparation
Firstly the most important thing to consider is the preparation of your sample before it is measured. 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 you were to take the sample from the top of the container it will not contain the smaller particles, giving you a biased measurement. The sample should be correctly mixed before a measurement is taken.
Wet samples have also to be correctly dispersed in a liquid dispersant. Using the wrong dispersant can cause the sample to stick together in lumps, float on the surface or even dissolve. The sample and dispersant should be checked to see if they are suitable before a measurement is made. There are many ways to prepare your sample to ensure a perfect measurement.
Details on sample preparation are given in chapter 9.
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N o t e . It has been found that over half the problems encountered in measuring the sample have been caused by bad sample preparation. It should be obvious that if you make a bad measurement that no amount of analysing will give you a good result.Cleanliness of the optical system
Laser scattering is a high resolution optical method in which the lenses and cell windows are an integral part of the measurement zone. Dust or smears on the lenses 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 two corrects for such contributions. However this correction is first order only and excessive dirt on the optics degrades the instruments sensitivity.
You are recommended to ensure at all times that your lenses and cell windows are clean. Use the procedures described in chapter 11 for advice on cleaning the system.
If you are in doubt about the optical cleanliness then you can use the live display of scattered light to view the background measurement. By viewing this screen you will be able to judge if the optics are clean or not. This procedure is described in chapter 11.
Choosing a range lens
The Mastersizer has several range lenses available. For this initial measurement you will be using the 300RF lens on the Mastersizer S or the 45mm lens on the Mastersizer X. If you have followed the installation manual successfully then one of these lens will already be installed, if not go back to the installation manual and add the appropriate lens.
In future though you will have to know which lens to choose. There are two main things to consider - the size range of your sample and the method of dispersing your sample.
Size range of your sample
The choice of lens will depend on the size of the particles within the sample. Each range lens covers a different size range of particles. The table below gives these ranges.
Mastersizer X
Mastersizer S
Lens Size Range Lens Size Range
45mm 0.1 - 80 µm 300RF 0.05 - 880µm
100mm 0.5 - 180 µm 300mm 0.5 - 880µm
300mm 1.2 - 600 µm 1000mm* 4.2 - 3480µm
1000mm* 4.0 - 2000 µm
(* Used on the long bench Mastersizers only.)
You will have to use a lens that covers the size range of particles in your sample. For example if you have a sample with particles in the range of 2 microns to 10 microns, using the 1000mm lens will not allow you to measure the bottom range of the sample. Using the 300RF lens though will give you the correct range. You may have noticed a problem with the above statement. How do you know the size range of the sample before you have measured it? If you do not know the size range of your sample you will have to perform a test measurement. If the range lens you are using is cutting off the results then the result has a
characteristic look.
The measurement below shows a sample measured on the 0.5-900µm range lens (300mm lens on the Mastersizer S).
Each lens can be identified by removing the front lens cap. The name of the lens is engraved on the lens ring.
The graph shows that the distribution is cut off at the large size end. Clearly there is a significant amount of material at sizes above 900µm. Not only is this material missed in the measurement but the light scattered by that material also distorts the measurement of the material which is in the range. For such a material, the 4-3500µm range (1000mm lens on the Mastersizer S) would be more suitable as shown in the second graph below.
Particle Diameter (µm.) 0 10 20 0 10 20 30 40 50 60 70 80 90 100 10.0 100.0 1000.0 ILL 1870 Particle Diameter (µm.) 0 10 0 10 20 30 40 50 60 70 80 90 100 10.0 100.0 1000.0 10000.0 IL L 1871
