沉积物中有机氯农药超声提取分析方法研究

Study on the Ultrasonic Extraction Method of Organochlorine Pesticides in the Sediments

应用超声提取沉积物中的有机氯农药(OCPs),GC-ECD进行定量分析.研究了不同提取溶剂、提取时间、提取次数以及不同极性的毛细管色谱柱对沉积物中11种OCPs(六氯苯,α-HCH,γ-HCH,七氯,艾氏剂,δ-HCH,β-HCH,p,p′-DDE,o,p′-DDT,p,p′-DDD和p,p′-DDT)提取效率的影响,确定了沉积物中OCPs超声提取的最优条件:用正己烷/二氯甲烷(体积比为1∶1)作提取溶剂,提取60 min,提取1次,采用DB-1701毛细管色谱柱,GC-ECD定量测定可以得到较好的效果,提取效率均高于70%,满足美国环境保护局(USEPA)的要求.利用最优条件分析了辽东湾沉积物中的OCPs含量.结果表明,辽东湾沉积物中六氯苯,α-HCH,γ-HCH,七氯,δ-HCH,β-HCH,p,p′-DDE,o,p′-DDT,p,p′-DDD和p,p′-DDT均被检出;DDTs类以p,p′-DDT含量最高,且以DDE为主要的降解产物;HCHs以δ-HCH含量最高.与其他湖泊河流沉积物相比,辽东湾HCHs,DDTs及六氯苯含量相对较高.

The OCPs of the sediments were distilled with the ultrasonic extraction method and measured by GC-ECD. The extraction conditions were optimized by comparison with several organic solvents, the duration of ultrasonic, the steps of extraction and the different GC eolums. Results showed that the optimal conditions were obtained using the mixture of hexane and dichlormethane （ 1 ： 1 ） in one step for 60 rains and the recoveries of OCPs were all above 70%, which could meet the request of USEPA. Hexachlorobenzene, α-HCH,γ-HCH, heptachlor, δ-HCH,β-HCH,p,p′-DDE,o,p′-DDT,p,p′-DDD和p,p′-DDT） in the samples collected from Liaodong Bay were all detected using the above optimal conditions. The p,p′-DDT and δ-HCH were the dominating components of the DDTs and HCHs in the sediments taken from Liaodong Bay, respectively. Compared with other river/estuary sediments, the concentrations of HCHs, DDTs and hexachlorobenzene in sediments from Liaodong Bay were higher, which illustrated that the contamination of OCPs was serious in Liaodong Bay.