High polarity analyte(s) in aqueous media: Determination of L-PFOA and L-PFOS in ground water

Main text Track C key comparison on determination of L-PFOA and L-PFOS in ground water (CCQM-K156) coordinated by TUBITAK UME was completed in 2022. A subsequent comparison (CCQM-K156.1) was offered to those NMIs or DIs who did not get the chance to participate in the previous comparison or who would like to repeat this measurement challenge. This study provides the means for assessing measurement capabilities for determination of high polarity measurands in a procedure that requires extraction, clean-up, analytical separation and detection. Successful participation in CCQM-K156.1 demonstrates measurement capabilities in determining mass fraction of organic compounds, with molecular mass of 200 g/mol to 700 g/mol, having high polarity pKow > -2, in mass fraction range from 0.5 ng/kg to 500 ng/kg in aqueous media. Five NMIs and DIs participated in CCQM-K156.1 key comparison. SPE was applied in the sample pre-treatment and LC-MS was applied for detection. All participating laboratories applied isotope dilution mass spectrometry (IDMS) techniques for quantification. Participants established the metrological traceability of their results using certified reference materials (CRMs) from NMIs with stated traceability. The CCQM-K156.1 results for L-PFOA and L-PFOS range from 4.71 ng/kg to 9.36 ng/kg with a % RSD of 23.5 % for L-PFOA and from 4.62 ng/kg to 7.67 ng/kg with a % RSD of 18.6 % for L-PFOS. The KCRV and u(KCRV) for this comparison were the results of TUBITAK UME, since TUBITAK UME was a participant in the previous CCQM-K156 and its results agreed well with the CCQM-K156 KCRV. The KCRV was 9.36 ng/kg ± 0.98 ng/kg for L-PFOA and 7.01 ng/kg ± 0.94 ng/kg for L-PFOS. For L-PFOA, the result of SYKE agreed with KCRV, while the results of VNIIM, BAM and NMISA were biased low. As for L-PFOS, BAM, SYKE and NMISA results agreed with the KCRV, whereas VNIIM result was biased low. To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/ . The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).