Determination of analytical interferences for 4:2 fluorotelomer sulfonic acid in multiple agricultural matrices
By Christine M Fisher, Brian Ng, Pierluigi Delmonte, Elsie Peprah, Samanta Popol, Wendy Young, and Susan Genualdi
J Agric Food Chem
December 16, 2025
DOI: 10.1021/acs.jafc.5c12943
During analysis of corn snaplage, fiddleheads, and hay for per- and polyfluoroalkyl substances (PFAS) using a liquid chromatography-tandem mass spectrometry (LC-MS/MS) triple quadrupole method, a series of interferents were observed for 4:2 fluorotelomer sulfonic acid (4:2 FTS, z 326.9743). Liquid chromatography high-resolution mass spectrometry (LC-HRMS) and MS/MS were used to identify these interferents as corchorifatty acid F and other complex lipids capable of generating / 327.2177. Approaches to differentiate 4:2 FTS from these interferents included HRMS, scheduling alternate transitions in triple quadrupole methods to monitor for the presence of these interferents, and altering the chromatography conditions (e.g., C-18 vs C-18 PFP column). Importantly, reporting these findings and adding these interferents to the PFAS interference list (PIL) for 4:2 FTS raise awareness for the possibility of matrix interferences in these agricultural products and reduce future false positive and/or over-reporting of PFAS in complex samples.
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