Shimadzu LC MSMS PFAS analysis low density

[batuhanqq]

Hello, I need your help with something. I have a Shimadzu 8045 LC MS machine. I need to perform FTOH analysis at low temperatures for PFAS analysis, and I need to see levels down to 5 ppb. However, after 25 ppb, noise peaks increase in my analyses, and I can't analyze the FTOH peaks. The flow rate is 0.4 ml, and I have a specific gradient analysis. I use 10 mmol ammonium acetate and acetoitrile as buffer solutions. Do you think the Shimadzu's performance is sufficient for PFAS analysis? Is there another method I can try?

[H.Thomas]

Hi, there are certainly some things you can try. First I would use methanol instead of ACN. You could try to use 0.05% acetic acid or 5 mM ammonium fluoride as additives instead of ammoniun acetate.
I assume you already optimized voltages and temperatures of the MS? You could repeat this step after switching to methanol. You should also optimize the position of the spray needle.

Shimadzu has some application notes on PFAS analysis:
https://www.shimadzu.de/industries/envi ... index.html

This is one on the 8045:
https://www.ssi.shimadzu.com/sites/ssi. ... 2-PFAS.pdf

Hope this helps.