加速溶剂萃取-气相色谱法测定土壤中11种氯苯类化合物

GC Determination of 11Chlorobenzene Compounds in Soil with Accelerated Solvent Extraction

冷冻干燥样品以正己烷为萃取溶剂进行加速溶剂萃取,再将萃取液进行浓缩(干法);新鲜样品以正己烷与丙酮以体积比1∶1组成的混合液为萃取溶剂进行加速溶剂萃取,萃取液经脱水和硅酸镁小柱净化后,收集淋洗液,再将淋洗液进行浓缩(湿法)。采用气相色谱法测定上述浓缩液中11种氯苯类化合物的含量,采用Agilent DB-1701毛细管色谱柱分离,电子捕获检测器测定。11种氯苯类化合物的质量浓度在一定范围内与其对应的峰面积呈线性关系,方法的检出限(3.143s)为0.002~0.030mg·kg^(-1)。方法用于干法和湿法制备的土壤样品的分析,加标回收率为45.3%~140%,测定值的相对标准偏差(n=6)为2.7%~24%。

The freeze-dried sample was extracted by accelerated solvent extraction with n-hexane,and then the extract was concentrated(dry process).The fresh sample was extracted by accelerated solvent extraction with the mixture of n-hexane and acetone(volume ratio:1∶1);the extract was dehydrated and purified by magnesium silicate column;then the eluent was collected and concentrated(wet process).GC was applied to the determination of 11chlorobenzene compounds in the above concentrated solution.The analytes were separated on Agilent DB-1701 capillary chromatographic column and detected by ECD.Linear relationships between values of peak area and mass concentration of the 11chlorobenzene compounds were kept in definite ranges.Detection limits(3.143s)of the method ranged from 0.002to 0.030mg·kg^(-1).The proposed method was applied to the analysis of the soil samples prepared by dry process and wet process,giving values of recovery found by standard addition method and RSDs(n=6)of determined values in the ranges of 45.3%-140%and 2.7%-24%respectively.