Halogenated phenolic compound determination in plasma and serum by solid phase extraction, dansylation derivatization and liquid chromatography-positive electrospray ionization-tandem quadrupole mass spectrometry

A robust, sensitive and accurate method was developed for the simultaneous determination in plasma and serum of suite a halogenated phenolic compounds (HPCs) for which several are known to persist in the environment and analytically pure standards are available. Namely, 14 congeners of hydroxylated polybrominated diphenyl ethers (OH-PBDEs), six congeners of hydroxylated polychlorinated biphenyls (OH-PCBs), pentachlorophenol, pentabromophenol and the flame retardant tetrabromobisphenol A (TBBPA). Solid phase extraction (SPE) enriched the target compounds and cleaned up the samples as a result of efficient adsorption on a strong anion-exchange solid phase SPE cartridge (Oasis MAX). After final clean-up the HPCs were derivatized with dansyl chloride and analyzed by liquid chromatography-tandem mass spectrometry with electrospray ionization in positive mode (ESI(+)). Chromatographic separation was achieved on a Luna PFP(2) column (2 mm x 100 mm, 3 mu m particle size) with mobile phases of water and acetonitrile (both containing 0.1% formic acid). The addition of the dansyl moiety to the HPCs greatly improved analyte sensitivity as the electrospray ionization efficiency was enhanced. Instrument limits of detection (ILODs) for LC-ESI(+)-MS/MS analysis of the HPCs were in the range of 0.01-0.07 ng/mL and the method limits of quantification (MLOQs) were in the range of 0.02-0.15 ng/g. Recovery efficiencies of the suite of HPCs ranged from 64% to 118% with relative standard deviations from 2% to 12% from fortified bovine serum samples. The method was successfully applied for HPC determination in representative polar bear and snapping turtle plasma samples. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.