顶空固相微萃取-气相色谱-质谱法测定水中54种挥发性有机化合物

Determination of 54 volatile organic compounds in water by headspace solid phase microextraction and gas chromatography-mass spectrometry

目的建立顶空固相微萃取-气相色谱-质谱法(HS-SPME-GC-MS)同时测定水中54种挥发性有机化合物的方法。方法采用HS-SPME-GC-MS法同时测定水中54种挥发性有机化合物,对影响固相微萃取效率的纤维涂覆种类、萃取温度、萃取时间、样品的离子强度、解吸温度和解吸时间进行了优化。结果用75μm CAR/PDMS(Carboxen/聚二甲基硅氧烷)作为萃取头,样品在(50±2)℃下萃取30 min,在气相色谱仪进样口温度为220℃下解吸3 min后进行GC-MS测定。方法的线性范围为1.0μg/L^100.0μg/L,相关系数为0.990~0.999,检测限为0.45μg/L^1.46μg/L。回收率为83.1%~117%,相对标准偏差为0.69%~17.6%。此法用于测定污水、自来水、净化水样品,检出7种卤代烷烃化合物,如三氯甲烷、二氯一溴甲烷、一氯二溴甲烷、三溴甲烷等。结论该法前处理步骤简单、快速、准确,可用于水中挥发性有机化合物测定。

Objective A method was developed for the simultaneous determination of 54 volatile organic compounds in water samples by headspace solid phase microextraction（ HS-SPME） and gas chromatography-mass spectrometry（ GC-MS）.Methods The concentration of 54 volatile organic compounds was determined by HS-SPME-GC-MS. The experimental condition affecting their extraction and desorption,such as the type of fiber,temperature and time of extraction,ionic strength of the sample,temperature and time of desorption were optimized. Results The extractions were carried out in 75 μm CAR /PDMS（ carboxen / polydimethylsiloxane） fiber and the best results were found with 30 minutes of extraction at 50 ± 2 ℃,then3 minutes of desorption under the temperature of 220 ℃ for GC-MS determination. The linear ranges were 1. 0 μg / L-100. 0 μg / L. The correlation coefficients were 0. 990-0. 999. The detection limits of 54 kinds of VOCs were 0. 45 μg / L-1. 46 μg / L. The recoveries were 83. 1%-117% and the RSD was 0. 69%-17. 6%. The optimized method has been applied to determine the target volatile organic compounds in aqueous samples,such as wastewater,tape water and purified water. The analysis revealed the presence of seven halogenated alkanes at concentration between 0. 58 μg / L-32. 3 μg / L,such as chloroform,bromodichloromethane,dibromochloromethane and bromoform. Conclusion The method is simple,rapid,sensitive,and can be applied for determining the 54 kinds of VOCs in water with satisfactory results.