Analysis of hexafluoropropylene oxide dimer acid (HFPO-DA), commonly known as Gen-X, and related PFAS compounds

KC Hyland

What: Gen-X is an emerging polyfluorinated alkyl substance, hexafluoroprolyene oxide (HFPO-DA), and it with other novel PFAS is shown as part of a multi-component PFAS acquisition method. Gen-X and several PFOS-replacement compounds were optimized on the SCIEX Triple Quad™ 4500 System.

How: Existing methods for the suite of EPA standard PFAS chemicals were updated to include four novel PFOS/PFOA replacement chemicals; HFPO-DA, DONA, 9Cl-PF3ONS, 11Cl-PF3UdS. Sensitive LOQs of 10-50 ng/L for the 4 additional compounds were achieved in a single ten-minute LC-MS/MS acquisition on the SCIEX QTRAP® 4500 System.

Figure 1. PFAS compounds analyzed on the SCIEX QTRAP 4500 System. A) Peaks shown with 1 point Gaussian smoothing. B) Linear calibration curves for the 4 analytes ranging from 10 to 10,000 ng/L. C) Precision for 3 example analytes at Limit of Quantitation is shown. % CVs at lowest concentration remained at 10% or less for triplicate injections. At higher concentrations, %CV is equal to or better than 10%.

Table 1.  Optimized MRM transitions for 4 PFAS chemicals Added to EPA 537 suite.