State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
Guangzhou Quality Supervision and Testing Institute, Guangzhou, 510110, China.
Environ Pollut. 2019 Dec;255(Pt 2):113162. doi: 10.1016/j.envpol.2019.113162. Epub 2019 Sep 12.
Hexa-mix-chlorinated/brominated benzenes (HXBs), a group of newly found analogues of hexachlorobenzene (HCB) and hexabromobenzene (HBB), may exhibit similar environmental risks and toxicities as HCB and HBB, and therefore possess high interests in environmental and toxicological research. Yet information regarding HXBs in the environment remains scarce. In this study, we developed an isotope dilution method for quantitative and semiquantitative determination of five HXBs in fly ash, soil and air using gas chromatography high resolution mass spectrometry (GC-HRMS) in multiple ion detection mode. The samples were Soxhlet-extracted and purified with multilayer composite silica gel-alumina columns, followed by GC-HRMS detection. Identification of HXBs was conducted by the comparison between theoretical and detected mass spectra using paired-samples T test and cosine similarity analysis. Two HXBs (CBrCl and CBrCl) with reference standards were quantitatively determined while the rest three (CBrCl, CBrCl and CBrCl) without reference standards were semiquantitatively analyzed by sharing the calibration curves of CBrCl and CBrCl in cooperation with isotopologue distribution computation. The accuracies for CBrCl and CBrCl were 87.3-107.8% with relative standard deviations (RSD) of 2.8-5.0%. The method limits of quantification of the HXBs were 0.10 ng/g in fly ash and soil samples and 0.09 pg/m in ambient air samples. The recoveries ranged from 42.7% to 102.1% with RSD of 3.7-13.9%. This method has been successfully applied to the analysis of the HXBs in the environmental samples. The total concentrations of HXBs in the fly ash, soil and ambient air samples were 19.48 ng/g, 10.44 ng/g and 5.13 pg/m, respectively, which accounted for 10.6%, 0.4% and 10.8% of the corresponding total concentrations of HCB and HBB. This study provides a reference method for quantitative and/or semiquantitative analyses of novel mix-halogenated organic compounds, and sheds light on the full picture of HXBs pollution in the environment.
六氯苯（HCB）和六溴苯（HBB）的类似物——六溴二苯并对二恶英/呋喃（Hexa-BDE/DF）混合物，在环境中可能存在类似的环境风险和毒性，因此在环境和毒理学研究中具有很高的研究价值。然而，有关 HXBs 在环境中的信息仍然很少。在这项研究中，我们开发了一种使用气相色谱高分辨率质谱（GC-HRMS）在多离子检测模式下定量和半定量测定飞灰、土壤和空气中 5 种 HXBs 的同位素稀释法。样品用多层复合硅胶-氧化铝柱索氏提取和纯化，然后用 GC-HRMS 检测。通过使用配对样本 T 检验和余弦相似性分析比较理论和检测到的质谱来确定 HXBs 的存在。使用标准物质定量测定两种 HXBs（CBrCl 和 CBrCl），而其余三种（CBrCl、CBrCl 和 CBrCl）则通过共享 CBrCl 和 CBrCl 的校准曲线进行半定量分析，并结合同位素分布计算。CBrCl 和 CBrCl 的准确度为 87.3-107.8%，相对标准偏差（RSD）为 2.8-5.0%。HXBs 的方法检出限在飞灰和土壤样品中为 0.10ng/g，在环境空气样品中为 0.09pg/m。回收率范围为 42.7%-102.1%，RSD 为 3.7-13.9%。该方法已成功应用于环境样品中 HXBs 的分析。飞灰、土壤和环境空气中 HXBs 的总浓度分别为 19.48ng/g、10.44ng/g 和 5.13pg/m，分别占 HCB 和 HBB 相应总浓度的 10.6%、0.4%和 10.8%。本研究为新型混合卤代有机化合物的定量和/或半定量分析提供了参考方法，并阐明了环境中 HXBs 污染的全貌。
