高效氯氟氰菊酯在香蕉中的残留及其消解动态

采用气相色谱-质谱联用仪建立了香蕉中高效氯氟氰菊酯的测定方法,研究了高效氯氟氰菊酯在香蕉中的残留消解动态规律和最终残留量。香蕉样品经乙腈提取,氯化钠盐析分层后,N-丙基乙二胺(PSA)净化去除杂质后,以多反应监测模式(MRM)测定。试验结果表明：在0.002~0.500 mg/kg范围内,高效氯氟氰菊酯的质量浓度与对应的峰面积间呈良好线性关系。在添加水平为0.005 mg/kg,0.050 mg/kg,0.500 mg/kg下,高效氯氟氰菊酯的回收率为75%~96%。相对准偏差为3.3%~8.7%,可满足香蕉中高效氯氟氰菊酯残留检测的要求。云南和福建两地的田间试验结果表明,高效氯氟氰菊酯在香蕉中的半衰期分别为15.7 d和17.2 d,较易降解。在推荐剂量18.77 g ai/hm₂和1.5倍剂量28.15 g ai/hm₂,施药2~3次,距最后一次施药后21 d采集分析,香蕉中高效氯氟氰菊酯最终残留量为0.005~0.146 mg/kg。建议使用推荐剂量18.77 g ai/hm₂进行施药,施药次数2次,采收安全间隔期为21 d。

Residues and dissipation dynamics of lambda-cyhalothrin in bananas

A analytical method was developed for the determination of lambda-cyhalothrin in bananas by gas chromatography-mass spectrometry, and the dissipation and final residues of lambda-cyhalothrin in bananas were investigated. The samples were extracted with acetonitrile, then the extracts were added sodium chloride to stratify, and purified with N-propyl ethylenediamine, finally, the prepared samples were analyzed with GC-MS/MS at the multiple reaction monitoring modes. The results showed that there was a good linear relationship between the concentration of lambda-cyhalothrin in the range of 0.002~0.500 mg/kg and the corresponding peak area, with the spiked concentrations of 0.005 mg/kg, 0.050 mg/kg, and 0.500 mg/kg, the average recoveries varied from 75% to 96% with the relative standard deviation from 3.3% to 8.7%, which could meet the requirements of pesticide residues analysis. The results of field trials in Yunnan and Fujian showed that the half-lives of lambda-cyhalothrin in bananas were 15.7 d and 17.2 d, respectively, which was relatively easy to degrade. The application was sprayed for 2 to 3 times with the recommended dosage and 1.5 times of the recommended dosage(18.77 g ai/hm2 and 28.15 g ai/hm2), the residues of lambda-cyhalothrin in the bananas were 0.005~ 0.146 mg/kg with an harvest interval of 21 days. According to the results, we recommended to apply lambda-cyhalothrin two times at a dose of 18.77 g ai/hm2 with a safe interval of 21 days from harvest.