Determination of selected perfluorinated alkyl acids and persistent organic pollutants from a small volume human serum sample relevant for epidemiological studies

Abstract

A simple and fast method is presented for the determination of selected persistent organic pollutants (POPs) and perfluorinated alkyl acids (PFAAs), a subgroup of per- and polyfluorinated alkyl substances (PFAS) from a single 200μl aliquot of serum. Sample pretreatment starts with dispersive solid phase extraction of POPs to dichloromethane–hexane, which is immediately poured to cleanup column. POPs are eluted from column and concentrated for GC–MS/MS analysis. PFAAs are trapped to dispersant and are then extracted with ammonium acetate in methanol, concentrated and analysed with LC–MS/MS. For POPs, the limit of detection (LOD) ranged from 1.6 to 17pg/ml. Oxychlordane and dichlorodiphenyltrichloroethane had LODs in the upper end of this range as they were more labile and prone for interferences in the GC–MS/MS. For PFAAs, the LOD range from 0.027 to 0.068ng/ml. For POPs, the accuracy from Standard Reference Materials SRM 1589a and Arctic Monitoring and Assessment Programme (AMAP) intercalibration samples range from 74 to 127% and the repeatability (relative standard deviation, RSD%) from 2.0 to 15%. For PFAAs, the accuracy from AMAP samples ranged from 90 to 110% and from LOQ level spiked serum samples from 72 to 133%. Repeatability from AMAP and LOQ samples ranged from 1.6 to 7.3% and 5.5 to 15%, respectively. The presented method is useful in epidemiological studies where only limited amount of serum is available.