气相动态顶空进样-气相色谱-质谱法同时分析饮用水源水中57种挥发性有机物

Simultaneous Determination of 57 Kinds of Volatile Organic Compounds in Drinking Water Using A Dynamic Headspace Sampling Method Coupled to Gas Chromatography-Mass Spectrometry

气相动态顶空进样法是一种简单、环保和高灵敏度的样品前处理方法,在水样中挥发性有机物监测中的运用还有待研究。本研究应用气相动态顶空进样-气相色谱-质谱联用法测定饮用水源水中57种挥发性有机污染物,通过对比实验,优化了影响气相动态顶空进样方法灵敏度的主要因素,确定了较佳的样品盐度(30%)、平衡温度(40℃)、平衡时间(20 min)、吹脱捕集气流速(60 mL/min)及吹脱捕集时间(2 min)等前处理方法参数。采用优化的水样前处理条件,挥发性有机物标准曲线线性相关系数均大于0.9930(环氧氯丙烷为0.9821除外),方法检出限为0.2～7.0μg/L,实际饮用水源水样品加标回收率为82.1%～143%,精密度(RSD)为0.1%～24%(n=3)。建立的气相动态顶空进样法,水样前处理过程自动化,可同时对水中几十种挥发性有机物进行分析,提高了分析效率;与常见的对水样气相和液相中目标物同时进行吹脱捕集的吹扫捕集法相比,因无需直接接触水样而减少了样品对仪器的污染。

The Dynamic headspace sampling （D-HS） method is a simple, environmentally friendly and sensitive method. In this paper, we report the measurement of 57 kinds of VOCs in drinking water by using D-HS coupled Gas Chromatography-Mass Spectrometry （GC-MS）. Under optimum dynamic headspace sampling conditions, such as 30% salinity of sample, equilibrium temperature at 40℃, equilibrium time for 20 rain, purge flow of 60 mL/min and purge time for 2 rain, the obtained detection limit was 0.2 - 7.0 μg/L, with r 〉 0. 9930 （ except for epichlorohydrin at 0. 9821 ）. The obtained average recovery ratios were 82. 1% - 143% （ n = 3） in spiked drinking water samples, with RSD of 0. 1% - 24% （ n = 3 ）. The D-HS with automatic water pretreatment was applied to simultaneously measure dozens of VOCs in water samples with high efficiency. Compared with the widely applicable purge-and-trap method, the purge needle of D-HS does not contact with the aqueous sample, therefore, the contaminations from sample to instrument is avoided while using D-HS. D-HS, a labor saving method, is suitable for detecting dozens of VOCs in drinking source water.