加速溶剂提取-气相色谱法测定蔬菜中的有机氯农药

Determining organochlorine pesticides in vegetables by using accelerated solvent extraction and gas chromatography method

加速溶剂提取技术萃取蔬菜样品中的有机氯农药残留具有萃取速度快、溶剂用量少、选择性高等优点。用加速溶剂提取-气相色谱法测定蔬菜中的有机氯农药残留,其结果与国标法(GB/T5009,19-1996)和美国EPA法(3545)进行比较。结果表明:加速溶剂提取-气相色谱法能够对蔬菜中多种有机氯农药残留的提取和测定达到很好的效果,蔬菜中12种有机氯农药在两种质量分数(25和100ng·g-1)的添加的回收率在80%和125%之间,高于国标法,而与美国EPA的方法相当。用此法对南京市郊蔬菜中有机氯农药残留状况进行分析表明:南京市郊蔬菜中有机氯农药的检出率在76%和100%之间,DDTs是蔬菜中的主要有机氯农药残留,其次为六六六,分别占残留总量的48.5%~74.6%和14.0%~27.9%。10种试验蔬菜体内DDT和六六六的残留量均不超标,但此类物质可在食物链中富集和放大,仍会对农产品质量和人体健康构成潜在威胁。

Accelerated solvent extraction is few solvents consumption, rapid extraction and highly selective for extracting organic pollutants from solid materials, it is widely used in vegetable pesticide residue analysis. In this study, organochlorine pesticides in vegetables were extracted by accelerated solvent extractor and quantified by using gas chromatography equipped with a ^63Ni electron-capture detector （ECD） system. Recoveries of 12 representative organochlorine pesticides（p,p′-DDT, p,p′-DDE, p,p^-DDD, o3p′-DDT, o3p,-DDE, α-HCH,β-HCH, ）,-HCH, 6-HCH, hexachlorobenzene （HCB）, chlordane and heptachlor） spiked in carrot and spinach in different concentrations （25 and 100 ng-g^-1 ） were between 80% and 125%, and the relative standard deviation between 3% and 15%, which indicative of the new method was suitable for multiresidues analysis. As far as the recoveries, compared with national standard method and environmental protection agency method of America, the new method was higher than the former and similar to the latter. Residual levels of organochlorine pesticides in vegetables from vegetable base of Nanjing were also analyzed. Twelve representative organochlorine pesticides detectable occurrence were between 76% and 100%. DDT and HCH are the main residues in vegetables, account for 48.5% to 74.6%and 14.0% to 27.9% of all organochlorine pesticides residues detected, respectively Though the average levels were generally lower than maximum residue limit of national standard, it still be potentially dangerous to food quality and human health.