How to add temperature dependant solvents to the dispersant list
How can I add ethanol to my Zetasizer software?
You are using the Malvern Zetasizer and particularly like to determine particle size by dynamic light scattering (DLS). Great!
The standard configuration of the default software allows a lot of flexibility in terms of samples you can use. In principle, it is possible to measure in any solvent (or solvent mixture). All you need is enter the viscosity, refractive index and dielectric constant for any specific condition. In the software, this is a simple solvent (like Propan-2-ol defined at 25°C in the example screen to the right) as opposed to the buffers built with the complex solvent builder (like ICN PBS buffer with the 4 color puzzle symbol)}.
You may have noticed that certain dispersants (for example water, toluene) have a Malvern logo. This indicates that they are valid for any temperature. Occasionally, we get a question on how to add other dispersants that are valid for any temperature.
Why would you want to?
If your experiments include unattended runs at different temperatures then the viscosity changes. It is more convenient to let the software calculate the viscosity than manually entering it for all temperature steps.
To achieve this in the current software version, you have to use an updated config file. The advantage is that there is no need to wait for an entirely new software version. (Which has to go through lots of testing before release). Read on to find out how to add a config file version, which includes acetone, benzene, ethanol,…
What is a dispersant, what is a material?
The system detects the diffusion of objects in a liquid medium. The medium is the dispersant for the material of the moving objects. For example, if the sample is made up of proteins in a buffer then the protein molecules are the “material” and the buffer (i.e. the whole complex of water with salts, additives, etc) is the “dispersant”. Or for a colloidal sample of titanium dioxide nanoparticles in water, the dispersant would be water and the material would be TiO2. While the relevant properties [refractive index, absorption] of the material are relatively constant, the relevant parameters for the dispersant [refractive index, dielectric constant, viscosity] have a tendency to vary significantly with temperature due to the strong effect on viscosity.
Adding an updated configuration file [v 7.12]
The information about the dispersants (and the materials, coincidentally) is contained in the file SampleProperties.cfg This file resides typically in C:\ProgramData\Malvern Instruments\Zetasizer\SampleProperties.cfg. [The below instructions and configuration file are for Zetasizer software version 7.12]
Please note this is a hidden folder and you may just have to enter the folder C:\ProgramData\Malvern Instruments\Zetasizer\ directly into Windows Explorer to get there. Caution: overwriting the existing configuration file will overwrite any customized entries you may have created in the dispersant or materials manager. You should make a copy of your old file before overwriting, just in case, for example, name it SampleProperties-old.cfg.
Caution: overwriting the existing configuration file will overwrite any customized entries you may have created in the dispersant or materials manager. You should make a copy of your old file before overwriting, just in case, for example, name it SampleProperties-old.cfg.
To obtain the new file, right-click on the link or download this zip file SampleProperties and extract the file SampleProperties.cfg from the zip archive to your computer.
Finally, place the file into C:\ProgramData\Malvern Instruments\Zetasizer\SampleProperties.cfg [this is a hidden folder, so to access it you have to open File Explorer and enter C:\ProgramData\Malvern Instruments\Zetasizer\ directly into the File Explorer bar]
Start the Zetasizer software and it now includes some additional solvents {like Ethanol, Benzene, Acetone, …} when setting up an SOP or making a manual measurement.
There are also a range of new materials available in this version, so another reason to update. The temperature dependent data came from a fit to the parameters at 5 different temperatures, for viscosity, refractive index, dielectric constant.
Hope the above can facilitate some temperature dependent trend measurements for dynamic light scattering for you.
Can I use the Zetasizer for studying…?
Previously
- New Nanosizer users – quick guide to perfection
- What is the Zeta potential deviation?
- Refractive index for nanoparticles – is it required?