State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, People's Republic of China.
J Chromatogr A. 2020 Dec 20;1634:461715. doi: 10.1016/j.chroma.2020.461715. Epub 2020 Nov 13.
A compound-specific chlorine/bromine isotope analysis (Cl-/Br-CSIA) method was developed using gas chromatography-quadrupole mass spectrometry for polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), which are toxic to human health and are frequently detected in various abiotic and biotic media. For PCB congeners, the molecular ion method for a concentration of 0.5-10.0 ppm, a dwell time of 20-100 ms, a relative EM voltage of 200 V, an electric current of 34 μA, and an ionization energy of 70 eV was determined as the most suitable scheme, which obtained standard deviations (SDs) of chlorine isotope ratios ranging from 0.00008 to 0.00068. As for the PBDE congeners, the lowest SDs, ranging from 0.00050 to 0.00172, were determined using the top four ion method with a concentration of 5-10 ppm and a dwell time of 20-50 ms. Both the chlorine and bromine isotope ratios showed strong concentration dependencies. Therefore, external standardization or detecting chlorine and bromine isotope ratios at a uniform concentration level is necessary to eliminate the concentration effect. In addition, C-correction is critical to remove interference from carbon isotopes. This newly developed Cl-/Br-CSIA method successfully determined the chlorine/bromine isotope ratios of PCBs/PBDEs in technical mixtures and traced the chlorine/bromine isotope ratio variations of PCBs/PBDEs in photodegradation experiments, thereby suggesting that it is a promising tool for assessing the sources and transformation processes of PCBs and PDBEs in the environment.
开发了一种使用气相色谱-四极杆质谱法对多氯联苯 (PCBs) 和多溴二苯醚 (PBDEs) 进行特定氯/溴同位素分析 (Cl-/Br-CSIA) 的方法，这些物质对人类健康有毒，并且经常在各种非生物和生物介质中检测到。对于 PCB 同系物，确定了最适合的方案，即浓度为 0.5-10.0ppm、停留时间为 20-100ms、相对 EM 电压为 200V、电流为 34μA、电离能为 70eV 的分子离子法，得到的氯同位素比标准偏差 (SDs) 范围为 0.00008-0.00068。对于 PBDE 同系物，使用浓度为 5-10ppm、停留时间为 20-50ms 的前四个离子法，得到的 SDs 最低，范围为 0.00050-0.00172。氯和溴同位素比均表现出强烈的浓度依赖性。因此，为了消除浓度效应，有必要进行外部标准化或在统一浓度水平下检测氯和溴同位素比。此外，C 校正对于消除碳同位素的干扰至关重要。新开发的 Cl-/Br-CSIA 方法成功地测定了技术混合物中 PCB/PBDE 的氯/溴同位素比，并追踪了光降解实验中 PCB/PBDE 的氯/溴同位素比变化，这表明它是评估环境中 PCB 和 PBDE 来源和转化过程的有前途的工具。
