苹果中氯氟氰菊酯残留降解研究

为了解苹果生产过程中氯氟氰菊酯的残留污染及其在苹果中的降解规律,用气相色谱法动态检测了大田苹果中氯氟氰菊酯残留量。结果表明,最后1次施药后苹果中氯氟氰菊酯的残留量顺序为:37.5g/hm2喷施3次>37.5g/hm2喷施2次≈18.8g/hm2喷施3次>18.8g/hm2喷施2次,喷药总量是影响农药残留的主要因素;施药后到采收前,果皮残留浓度是果肉的9～40倍,氯氟氰菊酯的降解为一级动力学模型,半衰期为17.6d,苹果果肉降解速率(T1/2=22.7d)比果皮(T1/2=16.9d)慢。以37.5g/hm2浓度喷3次,30d后苹果中氯氟氰菊酯残留量(<0.02mg/kg)远低于我国和欧盟等国家的最大残留限量要求。

Study on the degradation trends of cyhalothrin in apple fruit

In order to understand the contamination of cyhalothrin and its degradation trend in apple fuit,so as to guide apple safety production and to provide strategy of comprehensive safety system in apple production,dynamic degradation trend of cyhalothrin in apple fruit were monitored in field by gas chromatography with electronic capture detector.The results showed that cyhalothrin residues in apple fruit were in order of 37.5 g/ha sprayed three times> 37.5 g/ha sprayed twice ≈ 18.8 g/ha sprayed thrice > 18.8 g/ha sprayed twice.The spraying volume was the major factor affecting cyhalothrin residues in apple fruit.Cyhalothrin mainly remained in peel and was 9 to 40 times that in pulp.The degradation trend of cyhalothrin in apple fruit accorded with the first-order kinetic model with half-life of 17.6 days.The degradation rate of cyhalothrin in peel(T1/2 = 16.9 d)were faster than in pulp(T1/2 = 22.7 d),cyhalothrin may be more sensitive to light.After spraying for 30 d,cyhalothrin residues in apple fruit(<0.02 mg/kg)were far low than MRLs of China,EU and other countries.Cyhalothrin can be used in apple production for a long time.