Two trace analytical methods for determination of hydroxylated PCBs and other halogenated phenolic compounds in eggs from Norwegian birds of prey

Two new trace analytical methods are presented for identification and quantification of phenolic compounds in complex biological matrixes such as bird of prey eggs. One method is based on derivatization with methyl chloroformate prior to GC/high-resolution MS (HRMS) analysis in electron impact ionization mode. Alternatively, the underivatized phenolic analytes were separated and detected by HPLC coupled to time-of-flight MS (TOF-MS) in the negative ion electrospray ionization mode. For both methods, the egg samples were homogenized and dried with acidified sodium sulfate, cold column-extracted, and cleaned up by gel permeation chromatography and subsequently a Florisil column. Recovery rates for pentachlorophenol (PCP), tetrabromobisphenol A (TBBPA), and selected hydroxylated PCBs (HO-PCBs) from spiked hen's eggs (spiking level 1 ng/g of wet weight (ww)) were in the range of 56-98% for the HPLC/MS method and 57-108% for GC/MS including derivatization. Typical detection limits of the HPLC/TOF-MS method were 5 pg/g ww (1-2 pg injected) for HO-PCBs and PCP and 20 pg/g ww (3 pg injected) for TBBPA. The GC/HRMS method achieved detection limits of approximately 1 pg/g ww in predatory bird eggs for all analytes (0.2 pg injected for derivatized TBBPA and 0.05 pg injected for derivatized HO-PCBs and PCP). Eight eggs from four different Norwegian predatory bird species were analyzed. The concentrations determined with the two different quantification methods corresponded well with each other. PCP and TBBPA were found in all samples at concentrations up to 1350 and 13 pg/g ww, respectively (GC/HRMS values). A total of 55 penta- to nonachloro-HO-PCB congeners were detected in the eight eggs, 10 of those could be structurally identified. The maximum HO-PCB congener concentration was found for 4-HO-CB 187 in a peregrine falcon egg with estimated 388 pg/g ww. Another peregrine falcon egg was highest contaminated with sum HO-PCBs (estimated 2.1 ng/g ww). This level was 1.2 per thousand of the sum PCBs value for the same egg. Furthermore, indications were found that the HO-PCB congener distribution pattern could be species specific for predatory birds.