An increasing number of studies use blood obtained non-invasively to monitor organohalogen contaminants. However, blood can be a difficult tissue to analyze for organohalogen pollutants due to interferences from co-extracted proteins. We compared five methods for extracting polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides, and lipids from serum using National Institute of Standards and Technology Standard Reference Material 1589a PCBs, Pesticides, PBDEs, and Dioxins/Furans in Human Serum. Liquid:liquid (LLE), cavity dispersed microwave-assisted (MAE), open-focused microwave (OFM), solid-phase (SPE), and pressurized fluid (PFE) extraction techniques were compared. OFM extraction resulted in the optimal recovery of internal standards (IS). All methods yielded similar contaminant concentrations that agreed with the certified values for SRM 1589a, except for PBDE 47 concentrations determined by LLE, MAE, and SPE and several PCB congener concentrations determined following PFE. PBDE 47 concentrations were overestimated when IS recovery was poor (less than 30%) following LLE and MAE. Based on these findings, the OFM method was determined optimal. One procedural factor was found to affect contaminant concentrations; use of IS carrier solvents that were immiscible with serum (or when the serum was not directly physically mixed with IS) resulted in a 30% underestimation of organohalogen concentrations. Several methods for measuring serum lipids are also described, and results indicated that direct methods (colorimetric or enzymatic) provide more reproducible results that are in better agreement with the lipid reference value than gravimetric measurements from organic extracts. This study offers valid, novel alternatives for extraction beyond traditional extraction methods (e.g., LLE) for blood contaminant measurements.
Citation: Analytical and Bioanalytical Chemistry
Pub Type: Journals
blood, brominated flame retardants, extraction methods, lipids, organochlorine pesticides, plasma, persistant organic pollutants, polybrominated flame retardants, polychlorinated biphenyls, serum retardants