摘要
采用有机分析中不常用的25 m L进样系统,以增大进样量,降低检出限,建立了一种以吹扫捕集进行前处理,气相色谱-燃烧-稳定同位素质谱仪测定水中苯乙烯单体氢同位素的方法,同时考察了目标物单体氢同位素分馏的影响因素。结果表明,在充分吹扫捕集的情况下,目标物全部进入捕集阱进行吸附解析,不会引起目标物的单体氢同位素的分馏。在分流进样方式下,目标物以一定的分流比进入气相色谱仪,目标物的峰型尖锐,信号降低,目标物的单体氢同位素发生分馏,单体氢同位素值大幅降低;在不分流进样方式下,目标物的峰型较差,信号较强,目标物的单体氢同位素不会发生分馏。其在高中低各浓度(10.0、30.0、50.0、60.0、80.0、100.0μg·L-1)的平行性较好,检测下限为10.0μg·L-1,可以为单体氢同位素的分析方法开发提供一定的基础,并可以用于无氯代物的污染较重的场地。
Compound-specific isotope analysis(CSIA)with on-line gas chromatography-isotope ratio mass spectrometry(GC/IRMS)offers a versatile tool for characterizing the origins and fates of organic contaminants in the environment. However, one major drawback of CSIA in field studies is that GC/IRMS system is currently low in sensitivity. In this study, a method based on purge & trap and gas chromatography combustion-isotope ratio mass spectrometry was developed to determine hydrogen isotope of styrene in water.Use of large sample volume(25m L, which was not frequently used in organic analysis)lowered the detection limit. Under full purge-trap, all the targets were transferred into the trap and no isotope fractionation was observed. In the split injection mode, the targets were entered into gas chromatography at fixed ratio, and sharp peaks were obtained with decreased signals. The ratio of hydrogen isotope was significantly reduced due to fractionation of hydrogen isotope. In the splitless injection mode, the peaks of targets were wide with an acceptable tailing, but the signal was strong. No hydrogen isotope fractionation was observed, and the ratio of hydrogen isotope was comparable to that of direct injection. This method has a good parallelism at low, medium, and high concentrations(10.0 μg·L-1, 30.0 μg·L-1, 50.0 μg·L-1, 60.0 μg·L-1, 80.0 μg·L-1, 100.0 μg·L-1)with detection limit of 10.0 μg·L-1. Therefore, this method can be applied to analysis of hydrogen isotope in non-chloride pollution.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2015年第5期1017-1020,共4页
Journal of Agro-Environment Science
基金
中国地质大调查项目(12120113102700)
关键词
吹扫捕集-同位素质谱
苯乙烯
单体氢同位素
purge & trap
styrene
compound-specific hydrogen isotopic compositions
