盐析微萃取-气相色谱法测定饮用水中痕量甲苯

Determination of trace toluene in drinking water by salting-out microextraction-gas chromatography

采用正丁醇为萃取剂,硫酸铵为盐析剂,建立了盐析微萃取-气相色谱法测定饮用水中痕量甲苯的分析方法,并对影响相分离的各种条件进行了优化。当水相体积为10m L,萃取剂正丁醇为300μL,盐析剂硫酸铵为4.5g,萃取时间为10min时,甲苯在0.01-0.50mg·L^-1和0.50-25.00mg·L^-1浓度范围内与峰面积呈线性关系,相关系数分别为0.99987和0.99982,方法的检出限为0.002mg·L^-1,对于质量浓度为0.50mg·L^-1的甲苯进行7次反复测量,得到其相对标准偏差为4.3%。该方法用于饮用自来水和河水中痕量甲苯的测定,平均回收率分别为91.59%和92.17%。

A new method for the determination of trace toluene in drinking water by gas chromatography coupled with salting-out microextraction was developed. With the existence of salting-out agent of ammonium sulfate and solvent of butanol,the toluene was separated out with microsphere from the homogenous phase in the system. Various conditions influencing phase separation were optimized. When the volume of water 10 m L,a good extraction efficiency was obtained by using 300μL butanol as extraction solvent,4. 5g ammonium sulfate as salting-out agent,extracting for 10 min. Under the selected experimental conditions,there was a linear relationship between the peak area and toluene concentration in the range of 0. 01 - 0. 50mg·L^-1and 0. 50 - 25. 00mg·L^-1with the correlation coefficient of 0. 99987 and 0. 99982. The detection limit of this method was 0. 002mg·L^-1. The RSD was 4. 3% for seven times of determination of a sample with toluene content of 0. 50mg·L^-1. This method has been applied to the determination of trace toluene in drinking water with the recovery of 91. 59% and 92. 17%.