有机污染物稳定同位素在线测试技术研究

为了识别环境中有机污染物的来源和迁移转化,在线的单体稳定同位素分析(CSIA)是必不可少的关键技术,但是在实际应用中还存在问题.本文评价了目前已经开发的6种在线测定单体稳定同位素仪器的发展动态,包括气相色谱-同位素比值质谱计(GC-IRMS)、液相色谱-同位素比值质谱计(LC-IRMS)、直接引进-气相色谱-同位素比值质谱计(DI-GC-IRMS)、气相色谱-四极杆质谱计(GC-qMS)、气相色谱-多接收器电感耦合等离子体质谱计(GC-MC-ICPMS)、气相色谱-光强衰荡光谱仪(GC-CRDS).提出了在线测试中的5个值得注意的问题:①样品的预富集；②气相色谱(GC)和液相色谱(LC)分离；③多种仪器和多种方法选择使用；④有机化合物稳定同位素标准物质的开发；⑤安全保障.提出了三点建议:一是大力发展直接注入而不经过燃烧的有机污染物同位素测试技术,例如GC-qMS和GC-CRDS技术；二是继续开发研究GC-MC-ICPMS测定有机氯和有机溴同位素技术；三是快速研制有机化合物稳定同位素的国际标准物质.本文认为,在进行单体化合物同位素研究时应作多元素的同位素分析,而其最优的选择是采用直接样品注入而不经过燃烧的测试技术.

Research Progress on Stable Isotope Online Testing Technology for Organic Contaminants

Compound-specific isotope analysis (CSIA) online is an indispensable key technique for identifying the sources of organic contaminants in the environment and characterizing their transformation processes, but there are still some problems in practical applications. In this study, firstly, the development of six methods for online determination of compound-specific organic isotope analysis was introduced and reviewed, including Gas Chromatography-Isotope Ratio Mass Spectrometer (GC-IRMS), Liquid Chromatography Coupled-Isotope Ratio Mass Spectrometer (LC-IRMS), Direct Introduction-Gas Chromatography-Isotope Ratio Mass Spectrometer (DI-GC-IRMS), Gas Chromatography-Quadrupole Mass Spectrometer (GC-qMS), Gas Chromatography-Multicollector Inductively Coupled Plasma-Mass Spectrograph (GC-MC-ICPMS) and Gas Chromatography-Cavity Ring-Down Spectroscopy (GC-CRDS). Secondly, five noteworthy problems in online testing were proposed: sample pre-concentration, Gas Chromatography (GC) and Liquid Chromatography (LC) separation, selection of instruments and methods, the development of organic compound stable isotope standard material and safety control. Finally, three suggestions were proposed: 1) to develop vigorously the direct injection technology without combustion, such as GC-qMS and GC-CRDS, 2) to continually develop the determination technology for organic chlorine and organic bromine isotopes and 3) to rapidly develop international stable isotope standards for organic compounds. The new understanding in this study was that when multi-element isotope analysis was applied to study compound-specific isotopes, direct injection technology without combustion was the optimal choice.