Trace detection of perfluorooctanoic acid and perfluorooctane sulfonate in surface sediments using a liquid chromatograph coupled to an electrospray ionization single quadrupole mass spectrometer (LC-ESI–Q-MS)

Poly- and perfluoroalkyl substances (PFAS) are among the pollutants of environmental concern besides pharmaceuticals and personal care products, microplastics, and other persistent organic pollutants. Of all the different PFASs reportedly present in the environment, the most researched are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). In this study, these pollutants were detected using a precise, selective, and sensitive liquid chromatographic-electrospray ionization single quadrupole mass spectrometric (LC-ESI–Q-MS) method within a linear range of 0.002–0.02 μg/mL. The method developed was thereafter validated according to the ICH validation parameters. This method was used to monitor PFOA and PFOS in selected surface sediments collected within the environs of two prominent rivers in the KwaZulu-Natal province of South Africa: Umgeni and Palmiet Rivers. While the PFOA levels varied from not detected to 1.490 ng/g dw, and PFOS levels ranged from 0.206 ng/g dw to 0.426 ng/g dw, the total PFOA and PFOS concentration (∑ PFOA and ∑ PFOS) in the surface sediment samples collected were 7.50 ng/g dw and 2.79 ng/g dw, respectively. The percent positive occurrence of PFOA and PFOS in all the tested sediment samples was 81.8 % and 100 %, respectively. This study becomes an eye opener to the commencement of research works with respect to developing remediation strategies for the removal of PFAS in the environment, especially the African environment.