香蕉中2,4-滴残留的快速检测及其消解动态

利用超高效液相色谱-串联质谱建立了香蕉中2，4-滴残留的快速测定方法，研究了2，4-滴在香蕉中的残留消解动态和最终残留量。香蕉样品经乙腈提取，氯化钠盐析分层后，采用负离子电离，多反应监测模式（MRM）测定。结果表明:在1.0~10 μg/L范围内，2，4-滴的质量浓度与对应的峰面积间呈良好线性关系，检出限为0.001 5 mg/kg，定量限为0.005 mg/kg。在0.005、0.05和0.5 mg/kg 3个添加水平下，2，4-滴的平均回收率为93%~99%，相对标准偏差为2.5%~3.0%，可满足香蕉中2，4-滴残留检测的要求。田间试验结果表明，2，4-滴在香蕉中的消解半衰期为5.4 d，属易降解农药。最终残留试验结果表明，以有效成分分别为23、35和53 mg/kg的剂量施药，于60 d后采收时，香蕉中2，4-滴的残留量均<；LOQ。

Rapid determination and dissipation dynamics of 2,4-D in Musa paradisiaca

An ultra high performance liquid chromatography-tandem mass spectrometry method was developed to study the dissipation dynamics and final residues of 2,4-D in Musa paradisiaca. The M. paradisiaca samples were extracted by acetonitrile, salted out and stratified by sodium chloride. Using negative ion ionization and multiple reaction monitoring, the results showed that there was a good linear relationship between the concentrations of 2,4-D and the corresponding peak area in the range of 1.0 μg/L to 10 μg/L. The limits of detection and quantification of the method were 0.001 5 mg/kg and 0.005 mg/kg, respectively. The average recoveries was in the range of 93% to 99% with the relative standard deviations from 2.5% to 3.0% at three spiked levels of 0.005, 0.05 and 0.5 mg/kg. The method is suitable for the 2,4-D residues detection in M. paradisiaca. The results of field experiments show that the half-life of 2,4-D was 5.4 days, indicating that 2,4-D is a non-persistent and easily degradable pesticide. The final residue test results showed that 2,4-D was LOQ in the M. paradisiaca 60 days after harvest, at dosages of of 23, 35 and 53 mg/kg (effective component concentration), respectively.