On the 25th September, I presented a webinar on the new developments for the Mastersizer 3000 particle size analyzer & the new Mastersizer 3000E.

This webinar was very well attended, and can still be viewed on the Malvern website here. However, due to the significant number of attendees, not all questions could be answered ‘live’ – so I thought it might be useful to post answeres to the questions I did not get to during the event. For many issues, expanded details are available on our website, or by contacting me directly!

The example for the cohesive fine material wet/dry comparison, was that a TiO2 sample?The example provided in the webinar does relate to the dispersion of titanium dioxide.
Login levels are possible but can you also attach the basic ms3000 s/w to operators and extended s/w to method developers?It is possible to set different accesses levels within the Mastersizer 3000 software using the application’s security system. Using this it would be possible to prevent access to method development features for standard operators.
For the 3000E software, is it free of charge for updates?Maintenance releases for the Mastersizer 3000E will be provided free of charge. However, access to the full functionality of the Mastersizer 3000 software will require the purchase of a software upgrade.
We started using narrow mode for silicon powders instead of general and our results are not as clear, how can I fine tune this?In general, we would advise that the general purpose analysis model is used for measurements, unless you are measuring a sample with a very narrow particle size distribution (for example, a polymer latex standard). If you use the narrow mode analysis for standard measurements you may obtain a higher resolution result. However, there is a risk that you will see increased noise in the results as well.
Why there is no dry dispersion availability in MS 3000E? Any chances of getting dry dispersion on MS 3000E in coming months?We are planning to introduce a dry powder disperser for the Mastersizer 3000E system in the coming months. So, watch this space!
Are there any plans to update the software for the 3000 to also emulate Micro measurements?The Mastersizer 3000 / 3000E software includes a ‘virtual lens range’ advanced analysis option. This allows the data range and result calculation range to be set to match the Mastersizer Micro, and should therefore aid method transfer. Within the next month we will release an application note showing how this option works, focusing on method transfer for mining and mineral applications.
Can we fix different ranges (non regular) in particle size distribution axis­?In general, the particle size distribution axis is set to be a logarithmic axis, as this best reflects the capabilities of the laser diffraction technique. However, options are available to display the size axis using a linear scale. It can also be set to show the particle size is Phi units. Another feature which may help for this requirement is the User Sizes function. This enables users to display any size bands they require within size distribution tables. These can then be displayed on graphs using the Histogram display option.
Have you any experience in soil samples testing? As we are company dealing with soil surveys we we’d like to share your experience with us in Mastersizer application regarding to soil testing.­Soil analysis is an important application for the Mastersizer system. We can display size distributions in Phi units in order to help with the reporting of results for soils. A series of custom calculations are also available in the software to allow the soil type, degree of sorting, Kurtosis and Skewness.
Will auditors allow use of MS 2000 emulation in MS 3000 software for sample analysis­?The Mastersizer 2000 analysis mode is a standard analysis mode within the Mastersizer 3000 software, which has been tested according to Malvern’s software code of practice. It can therefore be considered to be a fully validated part of the software, and as such it is likely to be accepted by auditors. However, we would expect that users will need to justify their use of the Mastersizer 2000 analysis mode when submitting methods.
Is it possible to upgrade the ­Mastersizer Micro MAF5000­? ­There are no upgrades available for the Mastersizer Micro system. However, as a current product, it is still fully supported by Malvern in terms of on-going service and applications support.
Minimum sample volume is then of 120mL?The minimum volume which can be measured using the Mastersizer 3000E is 120mls. This requires the use of the Hydro SM dispersion unit.
Does the Basic 3000E use only the red laser? (ie it cannot be upgraded to the premium MS 3000?The Mastersizer 3000E only uses red light scattering. However, a back-to-Malvern upgrade is available if a user wants to extend the measurement range in the future.
Is it possible to gain an estimate for particle number within a sample as opposed to just a % that fall within a particular size? ­This can be done, but it will be a very rough estimate. You’d need to export the size distribution data to Excel. Along with the volume concentration.­­Multiply the %age in each band by the volume concentration to get the volume in each band. ­­Then, divide the volume in each band by the volume of a sphere which has a size equal to the size band mid-point­­.This will give you an approximate value for the number of particles within the size band.
I am currently using Nanosight technology to size particles in the nm range, this also gives an accurate calculation for the number of particles per ml in the sample, do you have anything that can do this for particles in the micron range?­­Yes – we have automated imaging systems (Morphologi G3 and FPIA3000) which can provide size and shape information for micron-sized particles. These would also give you a number count. App notes and product brochures are available on Malvern’s web site.
When I run a milliQ sample through the Mastersizer I see large particles coming up around 1300microns­. ­This peak comes up in every sample I run- could this be due to bubbles forming?­
The milliQ sample also comes up at 1-7 microns- how reliable is this peak?­
The peak at 1300 microns is unlikely to be due to bubbles. If you are sure that particles in this range are not present in your sample, then I would check to ensure that the system alignment and background are stable prior to measurement. If either of these are unstable then it could lead to a signal being observed at low angles which will then be interpreted as large particles.
If you need support in determining what is happening, and also in checking the results in the 1-7 micron range, please make contact with Malvern. We’d be glad to provide applications support. In order to do this, we’ll need you to send us some example measurement data.
What is the maximum concentration in weight percent that the Mastersizer will work?­This is dependent on the sample. However, typical measurement concentrations are in the range from 0.001v% to 0.0001v%.
­Is there any recommendation for the light energy range for the background and sample measurement?­For the background measurement, we should expect the maximum measured signal to be below 200-250 units. This will be seen on the first few detectors. We would then expect the background to reduce to below 20 units by detector 20.For the sample, the measured light scattering level depends on the material you are measuring. For example, large particles scattering light with higher intensity compared to small particles. For this reason, Malvern do not normally provide limits for the light energy range observed during the sample measurement. Instead, we provide advice on the measurement obscuration. The wet and dry method development application notes on the Malvern website provide good guidance as to the obscuration ranges you should use.
Can it see carbon?­We can measure carbon-based samples using the Mastersizer system. For example, the system is used to measure the size of carbon-black pigments. We have also applied the technique to sizing graphite samples which are used a lubricants.
­Is the instrument suitable for abrasive material?­Yes – abrasive materials can be measured. For example, in the case of dry powder dispersion, we offer ceramic venturi dispersers which can be used to disperse abrasives.
­What is the meaning of the Span (in the report) and why was not the IQR, a statistical key dimension, chosen instead?­The Span has historically been used to assess the width of the size distribution as part of a laser diffraction measurement. It is calculated by taking the difference between the 10th and 90th percentiles, and then dividing this by the median particle size. It is offered in the Mastersizer software as a parameter to enable specification transfer from older diffraction systems. If you wish to report the IQR then this can be done by using the custom calculation function in the Mastersizer 3000 software.
You mentioned that there were different Venturi geometries. Can you elaborate on this and discuss if the system can be used to measure pellets or granulated materials as well as fine powders?Two different venturi geometries are available for the Aero S dry powder disperser. The Standard Venturi is designed to minimise impaction of the particles during dispersion, and is therefore suited to the measurement of fragile materials. I would expect that this would work well for granulated materials. A High Energy venturi is also available – this includes an right-angled bend as part of the venturi design. Particles travelling through this bend will impact the wall of the venturi, which aids dispersion of strongly agglomerated materials. However, this is not recommended when measuring fragile particles, as these can be damaged when impaction occurs.
You showed a trend plot over the duration of a measurement. When measuring suspensions using the Hydro MV can the temperature be tracked over the duration of the experiment?­Yes – the temperature can be shown on the trend plot.
Can the dry powder measurement system be used with formulations of metered dose inhalers?­The Mastersizer 3000 system can be used to measure the active pharmaceutical ingredients and excipients used in metred dose inhalers. However, if you want to measure the spray produced by the MDI then we would normally recommend that use of the Spraytec system. This is provided with an ‘Inhalation Cell’ accessory which has been designed to help with measuring the output of inhaler devices.
Is this size solely for spherical particles or can we analyse something specific as platelets?Laser diffraction can be used to measure the particle size of non-spherical particles. However, it will report a spherical equivalent diameter for these, which is approximately equal to the diameter of the sphere with a similar volume to the measured particle.
Can this equipment be used to evaluate salad dressing/mayonnaise emulsions?Yes – the Mastersizer 3000 and Mastersizer 3000E systems can be used to look at these emulsions. All that is required is for you to select an appropriate dispersant. For example, when measuring mayonnaise, it is possible to disperse the sample in water. However, it is important to add a few drops of a 5% solution of a food grade surfactant to the water (for example, Tween 20 or Tween 80) to ensure the emulsion remains stable.
For cement and lime measurements which type of dispersion is recommended? Wet or dry?For most cement and lime measurements we use dry dispersion, as the measurement speed is rapid and reproducible results can be obtained. However, some customers also measure using wet dispersion. Typical dispersants used for wet dispersion measurements include ethanol and propan-2-ol.