高效液相色谱-串联质谱法分析马铃薯和土壤中甲基硫菌灵及其代谢物的降解动力学及残留量

Degradation Kinetics and Residue of Thiophanate-methyl and Its Metabolite in Potato and Soil by HPLC-MS/MS

[目的]确保甲基硫菌灵的安全使用。[方法]利用超高效液相色谱-串联质谱建立了马铃薯和土壤中甲基硫菌灵及代谢物多菌灵的检测方法,通过田间样品分析评价甲基硫菌灵及多菌灵在马铃薯上的消解趋势、残留水平。[结果]该方法的灵敏度、精密度和准确性等各项性能指标均满足农药残留分析要求,适用于马铃薯植株、马铃薯和土壤中甲基硫菌灵及多菌灵的测定;甲基硫菌灵在土壤中消解动态满足一级降解动力学方程,半衰期为11.5～11.9 d;在马铃薯植株消解动态中检出量均小于0.01 mg/kg;马铃薯最终残留均不大于0.01 mg/kg。[结论]建议70%甲基硫菌灵可湿性粉剂防治马铃薯环腐病,施药次数1次,拌种量为0.42～0.70 g a.i./kg种薯。

[Objective]The research aimed to ensure the safe use of thiophanate-methyl.[Method]Ultra-high performance liquid chromatography-tandem mass spectrometry was used to establish the detection method of thiophanate-methyl and metabolite carbendazim in potato and soil.The digestion trend and residual level of thiophanate-methyl and carbendazim on potato were evaluated by field sample analysis.[Result]The sensitivity,precision and accuracy of the method met the requirements of pesticide residue analysis,and were suitable for the determination of thiophanate-methyl and carbendazim in potato plants,potatoes and soil.The degradation of thiophanate-methyl in soil met the first degree dynamics,and its half life were11.5-11.9days;the amount of detection in potato plant digestion dynamics was less than0.01mg/kg;the final residue of potato was not more than0.01mg/kg.[Conclusion]It is recommended that70%thiophanate-methyl WP can prevent potato ring rot,the application frequency is one time,and the seed dressing amount is0.42-0.70g a.i./kg seed potato.