Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China; Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing, 100013, China; School of Public Health, Capital Medical University, Beijing, 100069, China.
Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing, 100013, China.
Chemosphere. 2019 Mar;218:223-231. doi: 10.1016/j.chemosphere.2018.11.076. Epub 2018 Nov 15.
Diazepam (DZP) is often found in source water and drinking water at dozens of nanograms per liter levels. The transformation of DZP in water chlorination disinfection process has aroused new concern because the toxic disinfection byproducts (DBPs) might be produced. However, the DBPs of DZP have not been fully identified, and their occurrence levels in drinking water have not been reported. In our chlorination experiment, five emerging DBPs of diazepam: (5-chloro-2-(methylamino) phenyl) (phenyl)methanone (BP-246), 6-chloro-1-methyl-4-phenylquinazolin-2(1H)-one (BP-271), N-(2-benzoyl-4,6-dichlorophenyl)formamide (BP-294), methyl-(2-benzoyl-4-chlorophenyl) (methyl)carbamate (BP-304 (1)) and 6-chloro-4-methoxy-1-methyl-4-phenyl-1,4-dihydro2H -benzo[d][1,3]oxazin-2-one (BP-304 (2)), were tentatively identified by high-resolution mass spectrometry and further characterized by nuclear magnetic resonance spectroscopy. We developed a trace analytical method for the analysis of these five DBPs in drinking water based on solid-phase extraction (SPE) followed liquid chromatography coupled with electrospray ionization tandem mass spectrometric detection. Ultrahigh sensitivities were achieved with limits of detection as low as 7 pg per liter. The recoveries at different spiking levels were all higher than 80% except for that of BP-246. Four of the DBPs and DZP were detected in real drinking water samples at concentrations ranging from several to dozens of nanograms per liter with relatively high detection frequencies. This is the first report on the existence of DZP-DBPs in drinking water. The method and results will be useful for further studies on the occurrence, toxicity, human exposure and control measures of these DBPs.
地西泮（DZP）经常以数十纳克/升的水平存在于水源水和饮用水中。由于可能会产生有毒的消毒副产物（DBPs），因此 DZP 在水氯化消毒过程中的转化引起了新的关注。但是，尚未完全鉴定 DZP 的 DBPs，也未报道其在饮用水中的出现水平。在我们的氯化实验中，鉴定出了地西泮的五种新兴 DBPs：（5-氯-2-（甲氨基）苯基）（苯基）甲酮（BP-246），6-氯-1-甲基-4-苯基-2（1H）-喹唑啉酮（BP-271），N-（2-苯甲酰基-4,6-二氯苯基）甲酰胺（BP-294），甲基-（2-苯甲酰基-4-氯苯基）（甲基）氨基甲酸酯（BP-304（1））和 6-氯-4-甲氧基-1-甲基-4-苯基-1,4-二氢 2H-苯并[d][1,3]恶嗪-2-酮（BP-304（2）），通过高分辨率质谱和核磁共振波谱进一步鉴定。我们开发了一种基于固相萃取（SPE）的痕量分析方法，用于分析饮用水中的这五种 DBPs，该方法结合了液相色谱与电喷雾串联质谱检测。检测限低至 7 pg/L，实现了超高灵敏度。除 BP-246 外，不同加标水平的回收率均高于 80％。在实际饮用水样品中，除 BP-246 外，有四种 DBPs 和 DZP 的浓度在纳克/升的数量级，检测频率较高。这是首次报道饮用水中存在 DZP-DBPs。该方法和结果将有助于进一步研究这些 DBPs 的存在、毒性、人体暴露和控制措施。
