title: Miniaturized selective pressurized liquid extraction of polychlorinated biphenyls and polybrominated diphenyl ethers from feedstuffs.
abstract: A new miniaturized pressurized liquid extraction (PLE) with in-cell purification method has been developed for the simultaneous extraction of endogenous prioritary and toxic polychlorinated biphenyls (PCBs) and environmentally relevant tri- to deca-brominated diphenyl ether (PBDE) congeners from different feed matrices. Parameters affecting the efficiency of the selective PLE process, such as sorbent:matrix ratio, volume and nature of the extraction solvent, PLE working mode, extraction time and temperature, and amount of co-sorbents, were optimized. n-Hexane and n-hexane:dichloromethane (1:1, v/v) were used as extraction solvents. 8-mL of organic solvents and 3.5 g of sorbents sufficed for complete sample treatment. Only 0.25 g of feed sample were required for accurate determination of the endogenous PCBs studied using gas chromatography with a micro-electron capture detector (GC-μECD) during method development, and for PBDE analysis using either GC-μECD or gas chromatography with negative chemical ionization-quadrupole mass spectrometry (GC-NCI-qMS). Gas chromatography coupled to ion trap detection working in tandem mode, GC-ITD (MS/MS), was used for final PCB confirmation. Additional purification of the sample extracts was not required. The performance of the complete PLE-based method was evaluated at two spiking levels, 0.4 and 4 ng/g wet weight. Recoveries in the range 60-120% were obtained for PCBs, while those of PBDEs ranged from 86% to 114% for most of the target analytes. The relative standard deviations were in general lower than 20%. The optimized procedure was applied to the determination of the investigated PCBs and PBDEs in a variety of feed samples.
authors.affiliation: Department of Instrumental Analysis and Environmental Chemistry, IQOG, CSIC, Juan de la Cierva 3, 28006 Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Pena-Abaurrea
authors.forename: J J
authors.initials: JJ
authors.lastname: Ramos
authors.forename: M J
authors.initials: MJ
authors.lastname: Gonzalez
authors.forename: L
authors.initials: L
authors.lastname: Ramos
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D055768:Halogenated Diphenyl Ethers / Q000032:analysis / Q000302:isolation & purification*; D059625:Liquid-Liquid Extraction / Q000295:instrumentation* / Q000379:methods*; D008904:Miniaturization / Q000295:instrumentation*; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000302:isolation & purification*; D011312:Pressure; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry
chemical_list: D055768:Halogenated Diphenyl Ethers; D011078:Polychlorinated Biphenyls