Dear Dr Rauch

Greetings

You are absolutely right.Micro FTIR is the answer.Though I am of a different field but one of my distant relatives worked on these instruments couple of years back.

Thanks

http://www.zapmeta.co.in/ws?q=ftir%20spectrometer%20price%20list&asid=in_gc5_30&mt=b&nw=g&de=m&ap=1t1

Many Thanks Mr. Alatabe for the additional information!

Kind regards!

Dear Dr Rauch

It depends alot on which types of particles that you will want to analyze. Ive only worked with vibrational spectroscopy methods so I dont know about other possibilities such as GC/MS, but when it comes to vibrational spectroscopy the common ones are: FTIR, Raman and NIR. You can also do some measurements with UV-vis but I havent been very successful with those on environmental samples.

FTIR is commonly used but there is a wide variety of different types available. My personal experience is that FTIR is very practical and robust but that the best results are obtained by ATR (and there you would need to consider whether you would prefer diamond or germanium, which both have its strengths).

Another option is Raman spectroscopy which has the advantage that it can typically go to smaller sizes than the FTIR and that water doesnt disturb the measurements. You can also measure materials that is inside other materials (often used for customs). You can however, dependent on which wavelength you use, encounter problems with additives.

Then there is NIR. This is a quite straightforward technique for bigger samples. It is often coupled wiht chemometrics and we did a project where we combined hyperspectral image analysis with multivariate data analaysis to measure environmental samples of microplastics down to 300 µm. (see source below) Smaller sizes may be harder as NIR vary significantly in penetrationdepth dependent on wavelengths. I also had a student that applied a handheld NIR for meso and bigger microplastics which worked well for those sizes (link to his work below).

Karlsson, T. M., Grahn, H., van Bavel, B., & Geladi, P. (2016). Hyperspectral imaging and data analysis for detecting and determining plastic contamination in seawater filtrates. Journal of near infrared spectroscopy, 24(2), 141-149.

http://www.diva-portal.org/smash/record.jsf?pid=diva2%3A852588&dswid=-7503

Thank you for all the answers. I have discussed microplastics analysis with one instrument manufacturer and he recommended two options, FTIR or Raman. An FTIR microscope costs around 60 000 USD depending on option (e.g. germanium or diamond ATR). The price for Raman imagine microscope costs about 200 000 USD. The FTIR microscope seems robust and practical, as also mentioned above by Therese Karlsson.