Mass-Labeled Fluorotelomer Alcohol Fragmentation Gives "False Positive" for Nonlabeled Fluorotelomer Alcohols with Implications for Consumer Product Analysis.

Volatile per- and polyfluoroalkyl substances (PFAS) are detected in various consumer goods, raising concerns over environmental fate and human exposure. Volatile PFAS are commonly analyzed by gas chromatography-chemical ionization-mass spectrometry. Mass-labeled standards are used for quantitative analysis of volatile PFAS and to ensure quality control. However, mass-labeled fluorotelomer alcohol (FTOH) analyzed in positive chemical ionization produces signals corresponding to nonlabeled (native) FTOH ions, resulting in false positives. This observation was attributed to deuterium or hydrogen abstraction of mass-labeled standards. Deuterium abstraction of deuterated standards, including -4:2 FTOH, C--6:2 FTOH, C--10:2 FTOH, and hydrogen abstraction of C-labeled standard C-8:2 FTOH are ionization artifacts that yielded responses for native FTOH / values. False positives for native (nonlabeled) FTOHs caused by the introduction of a mass-labeled surrogate can be controlled by blank subtracting or decreasing mass-labeled standard concentrations. Alternatively, different mass-labeled standards can also be used in sample analysis.