固相微萃取-气相色谱/同位素质谱法测定水中挥发性有机物单体碳同位素

建立了采用75μm碳分子筛/聚二甲基硅氧烷(CAR-PDMS)纤维的固相微萃取-气相色谱/同位素质谱联用方法测定水中挥发性有机污染物碳同位素。使用浸入式固相微萃取和顶空固相微萃取方法进行实验确定在低浓度条件下最佳δ13C测试方法。通过使用顶空固相微萃取前处理技术进行单体同位素分析分析灵敏度更高,应用CSIA技术对1,2-二氯乙烯,三氯乙烯,四氯化碳进行单体同位素分析,方法的检出限为70μg/L,与样本的标准偏差小于0.3‰。该法适用于水体中微量挥发性有机污染物的同位素组成测定。

Compound-specific carbon isotope analysis of volatile organic compounds in water by gaschromatography-isotope ratio mass spectrometry with solid-phase microextraction

A method for the determination of volatile compounds specific carbon isotope in aqueous phase by gas chromatography-isotope ratio mass spectrometry with solid phase microextraction using carboxen-PDMS fiber was established. Direct and headspace solid-phase microextraction (D-SPME, HS-SPME) methods were tested in order to determine the optimum conditions to obtain reproducible δ13C values at low concentration. Higher sensitivity was reached using headspace solid-phase microextraction, and the detection limits of the methods for cis-1,2-dichloroethylene, trichloroethylene and tetrachloroethylene are 70 μg/L. The standard deviation was 0.03%. This method is suitable for the compound-specific carbon isotope analysis of volatile organic compounds in aqueous phase.