河口及近岸海水中20种农药的固相萃取小柱富集-气相色谱测定方法研究

建立了河口及近岸海水中痕量有机氯和拟除虫菊酯类农药的测定方法。用C18与氨基混合填料固相萃取小柱富集海水中有机氯和拟除虫菊酯类农药、正己烷-乙酸乙酯(v:v,9:1)洗脱,洗脱液用氮气吹扫浓缩后进行气相色谱测定。考察了洗脱溶剂极性及体积、pH值和盐度等对萃取效果的影响。结果表明,pH值和盐度对萃取效果的影响不明显。优化实验条件下,方法的相对标准偏差(RSD)在1.0%～6.9%之间(10 ng/L,n=5),样品加标回收率除艾氏剂(29.7%)外,其它19种农药在59.8%～114.8%之间,方法检出限(DL,3σ)为0.19 ng/L～1.40 ng/L。实际样品测定结果也表明,建立的方法能很好地适用于河口及近岸海水中有机氯和拟除虫菊酯类农药的测定。

Determination of 20 pesticides in esturine and coastal seawater by SPE column enrichment-gas chromatography

A method for the determination of 20 organochlorine and pyrethroid pesticides in estuarine and costal seawater has been developed.The pesticide samples were extracted and enriched by an SPE cartridge packed with C18 and -NH2 modified C18 mixture,and eluted with hexane-ethyl acetate（V：V,9：1）. The eluate was concentrated by nitrogen sweeping and determined by gas chromatography with electron capture detector.The influences of polarity,volume,pH and salinity of the eluent on the extraction were investigated.The results showed that pH and salinity had no obvious effect.The RSDs were 1.0%～6.9%（10ng/L,n=5）.The recoveries for spiked seawater samples were 59.8%～114.8%for 19 pesticides except aldrin（29.7%）.The detection limits（3a） were 0.19～1.40ng/L.The method has been successfully used to investigate the distribution pattern of pesticides in Quanzhou Bay,China.