液液萃取处理样品-气相色谱法测定水中22种有机氯农药

GC Determination of 22 Organochlorine Pesticides in Water with Pretreatment of Samples by Liquid-liquid Extraction

采用正己烷作萃取溶剂提取并富集水样中有机氯农药(OCP),所得提取液经浓缩并定容为1.0mL后,用气相色谱法-电子捕获检测器测定22种有机氯农药。采用Rtx-CLPⅡ和Rtx-1701双柱法根据与标准物质的保留时间相比较进行定性;采用Rtx-CLPⅡ柱对被测组分按外标法进行定量。结果表明:各种农药质量浓度在1～80μg·L^(-1)范围内与峰面积呈线性关系。22种有机氯农药的方法检出限(3S/N)在1.5～5.6ng·L^(-1)之间。用标准加入法测得其回收率在73.3%～107.9%之间,相对标准偏差(n=7)在2.9%～14.8%之间。

Gas chromatography with electron capture detector was applied to simultaneous determination of 22 organochlorine pesticides（OCP＇s） in water.OCP＇s was separated and enriched from the water sample by extraction with n-hexane.The extract was concentrated and diluted to 1.0 mL with n-hexane.The double capillary chromatographic column practice,i.e.use of 2 columns of different polarity（the Rtx-CLPⅡcolumn and the Rtx- 1701 column） was adopted for identification of the OCP＇s by comparing values of t_R with reference materials,and quantification of the OCP＇s was performed by using the Rtx-CLPⅡcolumn with external standard method.Linear relationships between values of peak area and mass concentration of the 22 OCP＇s were found same in the range of 1-80μg·L^（-1）,with detection limits（3s/k） in the range of 1.5-5.6μg·L^（-1）.Recovery of the method was tested,giving values of average recovery ranged from 73.3%to 107.9%and RSD＇s（n=7） ranged from 2.9%to 14.8%.