A method for the low-level (ng g−1) determination of perfluorooctanoate in paper and textile by liquid chromatography with tandem mass spectrometry

The determination of perfluorooctanoate (PFO) in articles of commerce has become increasingly important to understand if treated products are a possible source of PFO. An LC–MS/MS method for the determination of PFO in paper and textile using a dual labeled 13C-PFOA internal standard was successfully developed and validated. Residues of PFO were determined using an isocratic, reversed-phase high-performance liquid chromatography (HPLC) method with an ammonium acetate/methanol buffer. Ions monitored were 413 (parent) and 369 (daughter) for PFO and 415 (parent) and 370 (daughter) for dual labeled 13C-PFOA internal standard. As a precaution against ubiquitous PFO that occasionally occurs in mobile phase or instrument components, two Hypercarb™ cartridges (4 mm) were placed before the HPLC injector. Any PFO that was captured by the cartridges was removed before each injection by flushing the system with 100% methanol prior to equilibration with the isocratic mobile phase. Overall recovery and standard deviation over a 3 day validation regimen for samples (n = 54–55) fortified with PFOA at 5, 50, and 200 ng g−1 were 114 ± 4.9% for textile and 110 ± 7.6% for paper. The results also established a limit of detection (LOD) of 1 ng g−1 in textile and 2 ng g−1 in paper based upon S/N of the 5.0 ng g−1 fortification versus the untreated paper and textile.