同步超声衍生萃取土壤中氯代酸性有机物

建立了土壤中酸性有机物的同步衍生萃取分析方法,实现了溶剂体积与土壤质量1:1萃取。将土壤、石英砂、Na4-EDTA和纯水充分混合,室温放置36 h左右使酸性有机物释放,并使水分挥发。将该状态的土壤置于衍生瓶,加入丙酮、五氟苄基溴溶液和K2CO3溶液,利用超声技术将酸性有机物的萃取和衍生同时完成,超声时间为30 min时达到最佳萃取衍生效果。萃取液用硅胶柱净化后,用气相色谱-负化学源质谱(NCI)11 min内完成检测。在5.0~250.0μg/L线性范围内,各组分线性系数r2>0.997,检出限在1.2~4.8μg/kg之间,加标回收率在66.2%~102.9%之间,相对标准偏差在8.4%~13%之间。用该技术对土壤样品分析取得满意结果。

Study on synchronized derivatization and extraction technology of chlorinated acidic organic compounds in soil

A synchronized extraction and derivatization method for acidic organic compounds in soil was established in this study.Soil,quartz sand,Na4-EDTA and pure water were fully mixed and then placed at room temperature for about 36 h to release acidic organic compounds and to volatilize water.After the soil in this state was placed in a derivative bottle,acetone,pentafluorobenzyl bromide solution and K2 CO3 solution were added.And then the extraction and derivation of acidic organic compounds were simultaneously accomplished by using ultrasound technology.The optimum extraction and derivatization efficiency were achieved when the ultrasonic time was 30 min.The extraction solution was purified by a silica gel column and then detected by gas chromatography-negative chemical ionization mass spectrometry(NCI)within 11 min.The linear ranges were from 5.0μg/L to 250.0μg/L with the linear coefficients higher than 0.997.The detection limits were between 1.2μg/kg and 4.8μg/kg.The spiked recoveries were between 66.2% and 102.9% with the relative standard deviation between 8.4%and 13%.Satisfactory results were obtained in the soil analysis with this technique.