I am having trouble quantifying 6:2-Fluortelomersulfonsäure (6:2-FTS) using LCMSMSMS because of contamination. The sample is river water or ultrapure water, concentrated 1000x by solid phase extraction (Oasis® WAX; Waters, Milford, MA, US) and analyzed by LCMSMSMS (Xevo TQ-S micro (Waters)). The calibration range is 1~50 µg/L, but even ultrapure water may produce a chromatogram equivalent to several tens of µg/L of 6:2-FTS. Teflon is not used in the analysis. Glass instruments are cleaned with acetone and plastic instruments are cleaned with methanol before use. If anyone has faced a similar problem, I would like to know how to solve it. Thank you in advance.
Hi Yoshifumi,
Have a look inside the cap of your solvents. All analytical solvents come with a Teflon linear under the cap. Therefore, there is a lot of contamination (mainly from PFOA and PFPeA) but also from FTS. We found one manufacturer supplying Methanol without a Teflon liner, and our background contamination dropped below ~5 ng/L. I strongly suggest that everyone involved in PFAS research contact their sales rep to source Teflon-free solvents. The more pressure manufacturers have from researchers, the quicker this will change.
Regards,
Brett
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