[方法]采用亲水作用色谱-串联质谱法研究了灭蝇胺及其代谢物三聚氰胺在大棚黄瓜上的残留降解动态,为大棚黄瓜中灭蝇胺的安全使用提供科学依据。[结果]50%灭蝇胺SP以田间推荐用量150 g a.i./hm2(对水600 kg/hm2)喷施1次后,灭蝇胺在大棚黄瓜上的残留量于药后5 d达到最大值,为0.230 mg/kg。以0.230 mg/kg为原始沉积量,灭蝇胺在大棚黄瓜上的残留降解动态符合一级动力学方程,半衰期为14.3 d。处理后28 d内,黄瓜样品中三聚氰胺的残留量一直在增加,但其残留量均低于灭蝇胺的残留量。在最后1次采样时(药后28 d),三聚氰胺和灭蝇胺的残留量趋于相同。[结论]以0.2 mg/kg为灭蝇胺在黄瓜上的最高残留限量,建议灭蝇胺在大棚黄瓜上的安全间隔期为7 d。 [Method] The residue degradation dynamics of cyromazine and its metabolite melamine on cucumber in greenhouse were studied by hydrophilic interaction chromatography - tandem mass spectrometry to provide a scientific basis for the safe use of cyromazin in greenhouse cucumber. [Result] After 50% fenfurylamine SP was sprayed once for 150 g ai / hm2 (600 kg / hm2) of water in the field, the residue of cyromazin on the greenhouse cucumber reached the maximum on the 5th day , 0.230 mg / kg. With 0.230 mg / kg as initial deposition, the residual degradation kinetics of cyromazin in greenhouse cucumber was in accordance with the first-order kinetic equation with a half-life of 14.3 d. Within 28 days after treatment, the residual amount of melamine in cucumber samples has been increasing, but its residual amount is lower than that of cyromazine residue. At the last sampling (28 d after treatment), the residual amounts of melamine and cyromazine tended to be the same. [Conclusion] The maximum residue limit of cyromazine on cucumber at 0.2 mg / kg was suggested. The safety interval of cyromazine on greenhouse cucumber was suggested to be 7 d.