Integration of five groups of POPs into one multi-analyte method for human blood serum analysis: An innovative approach within biomonitoring studies

Within this study, a new analytical strategy was developed and validated for the simultaneous determination of 78 organohalogenated contaminants in human blood serum, namely 40 flame retardants (FRs) including 7 “novel” brominated and chlorinated FRs (novel FRs), 19 perfluoroalkylated substances (PFASs), 11 organochlorine pesticides (OCPs) and 8 polychlorinated biphenyls (PCBs). The integral sample preparation procedure was implemented for the isolation of non-polar compounds, based on three-step solvent extraction using a mixture of n-hexane:diethylether (9:1, v/v), followed by purification using a solid-phase extraction (SPE) on a Florisil® column. For isolation of more polar and lipophobic analytes, the remaining fraction from the first extraction step was further processed, using a modified QuEChERS method. Depending on the polarity and volatility of target compounds, either gas chromatography coupled to (tandem) mass spectrometry (GC–MS/(MS)), or ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-MS/MS), was employed for their identification/quantification. Within the subsequent pilot study, the new validated procedure was successfully applied to the monitoring of organohalogenated contaminants in 38 samples of human blood serum obtained from Prague, Czech Republic. From 78 targeted analytes, 10 PFASs, 10 OCPs, 8 PCBs and 6 BFRs were detected in serum at concentrations above method quantification limits (MQLs). In the serum samples, the amounts of determined PFASs were in the range < 0.01–8.97 ng mL−1 (mean 0.631 ng mL−1), OCPs and PCBs ranged from <0.1–1626 ng g−1 lw (mean 40.0 ng g−1 lw) and < 0.1–481 ng g−1 lw (mean 63.3 ng g−1 lw), respectively.