安克锰锌在荔枝树上施用的残留代谢消解规律与安全性评价

安克锰锌是烯酰吗啉两个异构体和代森锰锌组成的多元混合制剂。试样经粉碎、溶剂浸泡提取、混合柱净化,用气相色谱测定烯酰吗啉和代森锰锌母体(CS2),液相色谱测定代谢物乙撑硫脲(ETU)。仪器最低检出量:烯酰吗啉为1.436×10-12g,代森锰锌母体1.326×10-10g,ETU2.5×10-10g,最低检出浓度依次为0.02、0.025、0.02mg/kg,方法回收率依次为86.4%～90.8%、89.2%～95.9%、89.10%～95.13%;标准偏差为0.53～4.34;变异系数为0.58%～4.62%。安克锰锌在果皮中的消解方程广西和广东分别为C=1.2719e-0.1975T和C=1.045e-0.1972T,半衰期(T/2)均为3.5d;土壤中分别为C=0.8734e-0.1187T和C=0.6171e-0.1146T,半衰期(T/2)=6d;最高剂量250倍、最多施3次,最短距收期7d,在果肉中均未检出,果皮和土壤中的残留仅分别为0.1385～0.1745mg/kg和0.3105～0.3415mg/kg,均低于欧共体规定代森锰锌MRL值0.5mg/kg。

Residual Dynamics of Acrobat in Lichee and Soil

Acrobat MZ is a mixture of dimethonorph and mancozeb. Dimethomorph and mancozeb were determined by GC, the metabolite ethylenethiourea (ETU) of mancozeb were determined by HPLC. The result showed that the minimum detectable amount were respectively 1.436×10-12 g to dimethomorph, 1.326×10-10 g to mancozeb and 2.5×10-10 g to ETU, the minimum detectable concentration to dimethomorph, mancozeb and ETU were 0.02 mg/kg, 0.025 mg/kg and 0.02 mg/kg, respectively. The average recoveries were 86.4% to 90.8% to dimethomorph, 89.2% to 95.9% to mancozeb and 89.1% to 95.1% to ETU, respectively. The standard deviation and coefficients of variation were 0.53% to 4.34% and 0.58% to 4.62%. The degradative equation of Acrobat MZ were C=1.271 9 e-0.1975 T in Guangxi and C=1.045 e-0.1972 T in Guangdong to Lichee skin, were C=0.873 4 e-0.118 7 T in Guangxi and C=0.617 1 e-0.114 6 T in Guangdong to soil. The half-lives were 3.5 days in Lichee skin and 6 days in soil. The minimum residue of Acrobat MZ in Lichee skin, flesh and soil were 0.138 5 to 0.174 5 mg/kg, ND and 0.310 5 to 0.341 5 mg/kg, respectively. With reference to the MRL (0.5 mg/kg) of EU, it was safe with 250 to 500 times dilution and spraying 2 to 3 times of 69% Acrobat MZ WDG.