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 (2mm×100mm, 3µm 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 0.01-0.07ng/mL and the method limits of quantification (MLOQs) were in the range of 0.02-0.15ng/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.

Organohalogenated contaminants (OHCs) in the serum and hair of pet cats and dogs: biosentinels of indoor pollution.

Concentrations of different classes of organohalogenated contaminants (OHCs) viz., polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), bromophenols (BPs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and their metabolites were determined in cat and dog serum and hair samples from Pakistan. The major DDT metabolite, p,p'-DDE, was the major OHC in cat serum (N=20) and ranged between 1 and 2150 ng/g lipid weight (lw). p,p'-DDE was not detected in dog serum (N=16). In contrary to other OHCs, levels of ∑HO-PCBs were significantly higher in dog serum (median=6.0 ng/g lw) than cat serum (median=2.2 ng/g lw). Levels of most OHCs were significantly higher (p<0.05) in cat serum than those found in human serum from the same region, in particular for ∑PBDEs (ranged 1-1280 ng/g lw). Significantly lower levels of OCPs (p<0.05) were detected in dog serum than in human serum. The concentrations of ∑BPs were seven times higher in cat serum (median 112 ng/g lw) than dog serum (median 16 ng/g lw). To the best of our knowledge, this is the first time that NBFRs, e.g. 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE), and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH), were detected in cat and dog's hair. BTBPE had the highest detection frequency (30%) in the serum samples. In cat and dog hair samples, the order of importance of OHCs was ∑OCPs>∑NBFRs>∑PBDEs>∑PCB, with the highest concentrations being around 38 ng/g hair. In paired hair-serum cat samples (N=12), ∑DDTs (r=0.65, p=0.001) were significantly correlated, while for all other OHCs no significant correlations (p<0.001) were observed in both cats and dogs. Our findings on both hair and serum samples suggested that pet dogs do not bioaccumulate DDTs. Our results are also in agreement with the hypothesis that pets may serve as biosentinels for indoor pollution. This is the first study to document the presence of OHCs in pets from Pakistan and provides baseline information for future monitoring of OHCs in pets.