顶空毛细管柱气相色谱法测定水中苯系物的研究

Study on the Analysis of BTEX in Water by Headspace Gas Chromatography

采用顶空气相色谱-氢火焰离子化检测器法(HS-GC-FID)测定水中八种苯系物(包括苯、甲苯、乙苯、对二甲苯、间二甲苯、邻二甲苯、异丙苯、苯乙烯),对其分析条件进行了优化,详细讨论了分析过程中各因素对测定结果的影响,如:色谱柱极性、气液体积比、水浴温度和平衡时间等。结果发现:DB-FFAP极性石英毛细管柱可以实现了水中苯系物各组分的完全分离。在气液体积比为1∶2时、水浴温度为50℃平衡40 min后进行测定,获得了最佳实验效果,同时加入适量的氯化钠可以提高灵敏度。该方法条件下,苯系物各组分线性方程的相关系数均大于0.999,方法检出限在0.85～4.44μg.L-1,加标回收率在98.7～103.6%之间,相对标准偏差小于6.8%(n=6)。该方法准确快捷、线性范围广,适用于饮用水和地表水中低浓度挥发性苯系物的测定。

A method for the determination of BTEX （including benzene, toluene, ethylbenzene, p-, m-, o-xylene, cumene, styrene） in water with headspace gas chromatography and flame ionization detector （HS-GC-FID） was developed in the paper. To characterize the performance of this method, several parameters were studied in some detail, such as the polarity of capillary column, the volume ratio of the gas phase and the liquid phase, the water bath temperature and equilibration time. It was found that the components could be separated with the DB-FFAP capillary column completely. The good results were attained with water-bathing at 50℃ for 40 minutes when the volume ratio of the gas phase and the liquid phase was 1： 2. Adding adequate solid sodium chloride could improve the method sensibility. The coefficients of linear equation for BTEX were higher than 0.999. The detection limits were in a range of 0.85 -4.44μg·L^-1. The recoveries were 98.7-103.6%. The relative standard deviations was less than 6.8% （n=6）. The method was accurate, quick with high performance and wide linear range. It was suit to determine the low concentration BTEX in drinking water and surface water.