Turci Roberta, Bruno Franco, Minoia Claudio
Laboratory of Environmental Hygiene and Industrial Toxicology, Salvatore Maugeri Foundation, Via A. Ferrata 8, 27100 Pavia, Italy.
Rapid Commun Mass Spectrom. 2003;17(16):1881-8. doi: 10.1002/rcm.1129.
A time- and cost-saving method for the congener-specific analysis of polychlorinated biphenyls (PCBs) in human serum has been developed and validated. After two fast extraction and clean-up steps, analyses were performed using gas chromatography coupled with mass spectrometry with single ion monitoring (GC/SIM-MS), either in electron impact (EI) or electron-capture negative ionization (ECNI) mode. For the determination of dioxin-like congeners, an improvement in EI-MS sensitivity is desirable and use of NI is thus preferred. The procedure was validated for 12 dioxin-like congeners by analyzing spiked samples on three different days and using (13)C(12)-labelled analogues as internal standards. When using an NCI source, the limit of quantification was assessed at 0.01 microg/L, except for PCBs #77 and #81, which cannot be reliably detected below 0.05 microg/L. For the lower chlorinated non-dioxin-like congeners, NI offers less selectivity because of limited fragmentation. Electron impact ionization and electron-capture negative ionization mode can therefore be considered to be complementary for the determination of PCB congeners in the general population.
已开发并验证了一种省时且经济的方法,用于对人血清中的多氯联苯(PCBs)进行同系物特异性分析。经过两步快速提取和净化步骤后,使用气相色谱-单离子监测质谱联用仪(GC/SIM-MS)进行分析,采用电子轰击(EI)或电子捕获负电离(ECNI)模式。对于二噁英类同系物的测定,提高EI-MS灵敏度是可取的,因此优先使用负电离模式。通过在三个不同日期分析加标样品并使用(13)C(12)标记的类似物作为内标,对12种二噁英类同系物的分析方法进行了验证。使用NCI源时,除了PCB #77和#81在低于0.05 μg/L时无法可靠检测外,定量限评估为0.01 μg/L。对于低氯代非二噁英类同系物,由于碎片化有限,负电离模式的选择性较低。因此,电子轰击电离和电子捕获负电离模式可被视为在一般人群中测定PCB同系物的互补方法。