How do you retrieve particle size information for high aspect ratio particles? The material I am working with are large in the lateral dimensions (5-40 micrometers) but only few tens of nanometers in the other dimension. Can both of these dimensions be retrieved from a Coulter Counter? If so, how? I am especially concerned in measuring a size distribution of the smaller of the two dimensions. I know red blood cells are quite often measured with Coulter Counters, and they also have a high aspect ratio so I'm inclined to think measurement is possible for my material also. Please advise.
Dear Sankalp,
Very interesting question. I think there are two aspects that are important in such a measurement:
1) that the solution is sufficiently diluted, so the particles pass only one at a time through the aperture. Therefore, the risk of particle overlapping and wrong reading is minimized.
2) Also, if there are disturbances in the path flow, the electrical pulses may vary. I learnt that the are some algorithms that you can use to remove noise from the electrical signals caused by changes of particle path flow.
This may help also:
ASTMF2149-01(2007) Standard Test Method for Automated Analyses of Cells-the Electrical Sensing Zone Method of Enumerating and Sizing Single Cell Suspensions
Good luck with your work!
Luiza
Dear Sankalp,
The electrical sensing zone technique measures a volume related size, not shape characteristics, as the response relates to the change of resistance in the medium by the particle. So, you may be able to measure the size of your particles. But there is an other limitation: the length of your particles may block the aperture. The risk is especially present in wider size distributions. Other techniques may be better, e.g. electron miocroscopy. Probably, there is a standard for asbestos fibers, which look fairly similar to your particles.
Success,
Henk.
Thank you for your suggestions. I suspected it might be a problem if these particles block the aperture. I was mostly curious since light scattering techniques is currently unavailable to me and my material needs to be dispersed in a liquid.
Dear Sankalp Kota,
Here is our new paper on size and shape parameter determination of windblown mineral dust particles:
Article Granulometric characterization of paleosols in loess series ...
Cheers,
Gyuri
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