Development of an HPLC-UV method for PFASs determination in environmental water samples: Insights into matrix effects

Per- and polyfluoroalkyl substances (PFASs) are a group of highly toxic compounds present in environmental water matrices. The development of an analytical approach capable of analysing and distinguishing PFASs is crucial to support the development of emerging PFASs degradation technologies. Most analytical detection methods rely on High-Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-MS), which entails considerable costs and is not easily accessible. Other technologies are focused on HPLC with ultraviolet detection (HPLC-UV), with a pre-concentration step; nevertheless, the uncertainty increases, reducing reproducibility. In the present study, an HPLC-UV method without pre-treatment was developed to quantify 5 perfluoroalkylcarboxylic acids (PFCAs): perfluoropropionic acid (PFPrA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA) and perfluorooctanoic acid (PFOA). This quantification was performed in ultrapure, tap, pit and drinking water treatment plant matrices, and they were assessed both individually and in mixture. The main novelty of this work was the methodical validation across real water matrices, which offers a thorough evaluation of its applicability, using IUPAC guidelines, and highlighting how these matrices affect analytical performance in a compound-dependent way. The limit of quantification for PFPeA, PFHxA, PFHpA and PFOA was less than 5 mg L^-1 in any water matrix and less than 10 mg L^-1 when analysed in mixture. PFPrA was the most difficult to quantify due to its short alkyl chain, and the calibration curve was only validated in ultrapure water. ANOVA tests were conducted and for PFHxA, PFHpA and PFOA significant statistical differences between matrices were not registered.