类二噁英类多氯联苯的双柱气相色谱分析方法研究

A method study of dual capillary column gas chromatography with electron capture detection for the determination of dioxin-like polychlorinated biphenyls

采用弱极性和中极性的双毛细管柱互补分离技术对样品中的类二噁英类多氯联苯进行定性定量分析．本文采用索氏提取技术从环境样品中提取出类二噁英类多氯联苯等有机物，经浓硫酸／高锰酸钾和氟罗里土柱净化浓缩后，利用双毛细管柱气相色谱法建立的两套保留值定性定量，解决了12种类二嗯英类多氯联苯和非类二噁英类PCBs同系物和有机氯农药共洗脱的问题，建立了12种类二噁英类PCBs的定性定量分析方法．利用气质联用（GC／MS）选择特征离子SIM技术验证方法定性的准确性，利用基质加标回收、平行样品分析和空白加标回收的方法测定了方法的准确度、精密度和方法检测限，并对土壤、沉积物、降尘样品进行了测定．结果表明，12种类二唿英类多氯联苯的加标回收率在82-109.8％之间，在US．EPA规定的70。140％范围之内；相对标准偏差在1．62—14．84％，均小于20％；方法检测限在1．1-6，2ng／kg，达到Pg／g水平．该方法应用于黄河三角洲地区样品中类二噁英类多氯联苯的分析，取得了满意的结果．

A new and simple method was developed for the determination of 12 dioxin-like polychlorinated biphenyls （dl-PCBs） in samples using complementary separation on a dual column system with low and intermediate polarities. PCBs were extracted from the sample by soxhlet extraction, concentrated and purified by a two-step clean-up with 98% sulfuric acid/permanganate and Florisil column, qualitative and quantitative analyses of dl-PCBs at Pg/g level were performed by the two retention data on dual capillary gas chromatography with a 6SNi electron capture detection （GC-ECD）, and the co-elution between 12 dl-PCBs and the bulk PCBs and pesticides was solved. The accuracy of qualitative analysis was confirmed by gas chromatography mass spec- trometry （GC/MS） using the selective ion mode （SIM） technique. This method was validated： accuracy was estimated from the recovery of spiked analysis from the matrix; precision was estimated from the relative standard deviation （RSD） of the duplicate analysis of the un-spiked sample. The recoveries of target analysts were found to be in the range of 82 ~ 109.8%, dropped in the range of certified value by US.EPA 70 ~ 140%, the RSDs of 12 dioxin-hke PCBs were in the range of 1.62 ~ 14.86%, and were all less than 20%. The application of this analysis method to the determination of dioxin-like PCB in dust-deposition, sediment and soil samples from the Yellow River delta was successful.