Indian River Research and Education Center, University of Florida/IFAS, Fort Pierce, FL 34945-3138, USA.
J Chromatogr A. 2010 Oct 8;1217(41):6327-33. doi: 10.1016/j.chroma.2010.08.004. Epub 2010 Aug 11.
The distribution of pyrethroid and phenylpyrazole pesticides in the water environment has raised public concerns because of their potential risks to ecosystem and human health. However, co-extraction of emulsifier type compounds (by liquid-liquid extraction, LLE) present in environmental samples can present a challenge for quantifying typically low concentrations of pesticides. Several methods were evaluated for breaking emulsions in problematic environmental surface water samples extracted by LLE using methylene chloride. Target pesticides included 11 typical pyrethroid and phenylpyrazole pesticides commonly used in agricultural and landscape insect pest control. The most effective method was selected for validation in fortification studies with GC-ECD analysis. The average recoveries of spiked pyrethroid and phenylpyrazole pesticides were 88.2-123.4% for water samples with moderate emulsions and 93.0-117.4% for water samples with severe emulsions. Recoveries of the pesticides ranged 81.0-126.4% (water samples with moderate emulsions) and 95.9-110.6% (water samples with severe emulsions) for lowest fortification level (5-20 ngL(-1)), 88.2-123.4% (water samples with moderate emulsions) and 93.0-117.4% (water samples with severe emulsions) for middle fortification level (10-40 ngL(-1)), and 90.2-119.9% (water samples with moderate emulsions) and 91.2-105.9% (water samples with severe emulsions) for highest fortification level (50-200 ngL(-1)). Relative standard deviations of pesticide recoveries were usually < 10%. Results indicate that this method is a robust and reproducible option for LLE of pyrethroid and phenylpyrazole pesticides from emulsion-prone surface water samples.
拟除虫菊酯和苯并吡唑类农药在水环境中的分布引起了公众的关注，因为它们对生态系统和人类健康存在潜在风险。然而，环境样品中乳化剂型化合物（通过液液萃取，LLE）的共萃取给通常浓度较低的农药定量带来了挑战。评估了几种方法来打破用二氯甲烷通过 LLE 提取的有问题的环境地表水样品中的乳液。目标农药包括在农业和景观害虫防治中常用的 11 种典型的拟除虫菊酯和苯并吡唑类农药。选择最有效的方法用于通过 GC-ECD 分析进行加标研究验证。在中等乳化的水样中，添加的拟除虫菊酯和苯并吡唑类农药的平均回收率为 88.2-123.4%，在严重乳化的水样中为 93.0-117.4%。在最低加标水平（5-20 ngL(-1))时，农药的回收率范围为 81.0-126.4%（中等乳化水样）和 95.9-110.6%（严重乳化水样），在中间加标水平（10-40 ngL(-1))时，回收率为 88.2-123.4%（中等乳化水样）和 93.0-117.4%（严重乳化水样），在最高加标水平（50-200 ngL(-1))时，回收率为 90.2-119.9%（中等乳化水样）和 91.2-105.9%（严重乳化水样）。农药回收率的相对标准偏差通常<10%。结果表明，该方法是一种从易乳化地表水样品中萃取拟除虫菊酯和苯并吡唑类农药的稳健且可重复的选择。
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