索氏提取-气相色谱法测定高含水率土壤中21种酚类化合物

高含水率土壤样品与无水硫酸钠混合均匀后,以二氯甲烷-正己烷(2+1)混合液为提取剂进行索氏提取,提取液经氢氧化钠溶液净化,再经酸化后由二氯甲烷-乙酸乙酯(4+1)混合液提取,最后进行浓缩,采用气相色谱法测定浓缩液中21种酚类化合物的含量。用HP-5色谱柱(30m×0.25mm,0.25μm)分离,氢火焰离子化检测器检测。21种酚类化合物的质量浓度均在1.0~100.0mg·L^-1内与其对应的峰面积呈线性关系,检出限为0.01~0.07mg·kg^-1。以空白样品为基体进行加标回收试验,所得回收率为71.4%~95.1%,测定值的相对标准偏差(n=6)为1.0%~11%。

GC Determination of 21 Phenolic Compounds in High MoistureContent Soil with Soxhlet Extraction

After mixing with anhydrous sodium sulfate evenly,the sample of high moisture-content soil was extracted(Soxhlet)with the mixture of dichlormethane and hexane(2+1)as extractant.The extract was purified by sodium hydroxide solution.After acidification,the above solution was extracted with the mixture of dichlormethane and ethyl acetate(4+1),and finally concentrated.GC was applied to the determination of 21 phenolic compounds in the concentrated liquid.The analytes were separated on HP-5 chromatographic column(30 m×0.25 mm,0.25μm)and detected by FID.Linear relationships between values of peak area and mass concentration of the 21 phenolic compounds were kept in the same range of 1.0-100.0 mg·L^-1,with detection limits in the range of 0.01-0.07 mg·kg^-1.On the base of blank sample,test for recovery was made by standard addition method;values of recovery found were in the range of 71.4%-95.1%,with RSDs(n=6)of determined values in the range of 1.0%-11%.