百菌清及其代谢产物(4-羟基百菌清)在油麦菜及土壤中的残留降解研究

Research on the residue and degradation dynamic of chlorothalonil and its metabolite (4-hydroxy chlorothalonil) in Lactuca sativa and soil

中文关键词:  百菌清  4-羟基百菌清  液相色谱-串联质谱法  气相色谱法  残留降解

英文关键词:chlorothalonil  4-hydroxy chlorothalonil  gas chromatography  liquid chromatography-tandem mass spectrometry  residue degradation

中文摘要:

      目的 建立气相色谱法(gas chromatography, GC)和液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)测定油麦菜及土壤中百菌清及4-羟基百菌清残留的方法, 同时研究油麦菜及土壤中百菌清及4-羟基百菌清的残留降解规律。方法 油麦菜和土壤中的百菌清分别采用乙腈溶液匀浆提取和振荡提取, 使用固相萃取柱净化, 气相色谱法带电子捕获检测器测定; 油麦菜和土壤中的4-羟基百菌清分别采用乙腈溶液匀浆提取和振荡提取, 氮吹至近干用甲醇复溶后过0.2 μm滤膜净化, 进LC-MS/MS测定分析。结果 在0.01~5 mg/L范围内, 百菌清及4-羟基百菌清均线性良好; 在添加量均为0.01~1 mg/kg时, 百菌清在油麦菜和土中的添加平均回收率分别为78.5%~79.8%、79.2%~82.4%, 相对标准偏差(relative standard deviation, RSD)分别为3.01%~7.21%、5.06%~5.95%。4-羟基百菌清在油麦菜和土中的添加平均回收率分别为96.2%~116.7%、102.1%~113.9%, RSD分别为4.57%~6.22%、2.99%~4.57%。百菌清及4-羟基百菌清在油麦菜及土壤中的消解动态均符合方程Ct=C0e?kt: 百菌清在油麦菜中的半衰期为1.7 d, 在土壤中半衰期为7.5 d, 4-羟基百菌清在油麦菜中的半衰期为2.0 d, 在土壤中半衰期为7.5 d。结论 该方法简单快速, 可同时测定百菌清及其代谢物,上述结果可为今后安全、合理、高效使用百菌清提供一定的参考价值。

英文摘要:

      Objective To establish a method for determination of chlorothalonil and 4-hydroxy chlorothalonil in Lactuca sativa and soils by gas chromatography (GC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), and investigate the degradation dynamic on residue of chlorothalonil and 4-hydroxy chlorothalonil. Methods Pesticide residues were extracted by acetonitrile, and then there were two steps, one for chlorothalonil and the other for 4-hydroxy chlorothalonil. Chlorothalonil was purified by solid phase extraction, and determined by gas chromatography-electronic capture detector (GC-ECD); 4-hydroxy chlorothalonil was redissolved with methanol, filtered before determination by LC-MS/MS. Results There were good linear relationship for chlorothalonil and 4-hydroxy chlorothalonil in the range of 0.01~5 mg/L. The recoveries of chlorothalonil were 78.5%~79.8% in Lactuca sativa (RSD=3.01%~7.21%) and 79.2%~82.4% in soils (RSD=5.06%~5.95%) at the 3 spiked levels of 0.01, 0.1, 1 mg/kg. The recoveries of 4-hydroxy chlorothalonil were 96.2%~116.7% in Lactuca sativa (RSD= 4.57%~6.22%), and 102.1%~113.9% in soils (RSD=99%~4.57%), respectively. The results indicated that the degradation of chlorothalonil and 4-hydroxy chlorothalonil in Lactuca sativa and soil could be described with equation: Ct=C0e?kt. The half-life of chlorothalonil was 1.7 d in Lactuca sativa and 7.5 d in soil, respectively. The half-life of 4-hydroxy chlorothalonil was 2.0 d in Lactuca sativa and 7.5 d in soil, respectively. Conclusion This simple method can be used to determine chlorothalonil and its metabolite simultaneously. It also can provide certain reference value for safely, reasonably and efficiently use of chlorothalonil.