氯吡脲在猕猴桃中的残留动态研究

Study on residue dynamics of forchlorfenuron in kiwifruit

【目的】研究不同浓度氯吡脲在猕猴桃中的残留动态,掌握潜在风险,指导安全生产。【方法】以猕猴桃为研究试材、氯吡脲残留量为研究对象,通过密集采样测定,考察了5、10、20、50、100 mg·L-1等5种不同使用浓度氯吡脲在猕猴桃中的残留动态、降解率、半衰期及安全使用间隔期。【结果】猕猴桃中氯吡脲降解符合一级动力学消解模式。猕猴桃中氯吡脲残留量逐渐减少;相同时间间隔,氯吡脲浓度高的降解绝对量高、浓度低的降解绝对量低;氯吡脲在猕猴桃中的降解速度较快,平均半衰期为4.5 d;各使用浓度的降解率变化趋势基本一致,前期降解较快,后期变化相对较小。用药后26 d降解率均可达95%,用药后36 d降解率均可达99%,用药后56 d,仅用药浓度为50 mg·L-1和100mg·L-1的样品可检出低含量的氯吡脲,第66天后各样品均未检出氯吡脲。各浓度处理的安全间隔期分别为18 d、22d、27 d、31 d、34 d。【结论】由于猕猴桃果实生长时间较长,成熟采摘时氯吡脲残留量远低于国家标准规定限量(0.05mg·kg-1),一般不会产生质量安全风险。

[Objective]The paper studied the residual dynamics of forchlorfenuron in kiwifruit, with the purposes of exploring the potential risk as well as providing some guidance for safe application. [Method] Forchlorfenuron residue contents （FRC） in kiwifruit were studied by dense sampling, residual dynamics, degradation rate, half life and safety interval were tested at 5 different concentrations： 5 mg＂ L-1, 10 mg- L-1, 20 mg＇L-1, 50 mg＇L-1 and 100 mg.L-1. [Result]The results showed that the degradation of the forchlorfenuron in kiwifruit abided by the first order kinetics digestion mode. FRC decreased gradually and absolute degradation rate was relatively higher for high forchlorfenuron concentration and lower for low concentration at same time intervals. Forchlorfenuron degraded quickly in kiwifruit, the average half-life was 4.5 days, the degradation tendency were almost the same for different concentrations, which was quick in the initial period and relatively slow in the late, The degradation rate could reached up to 95% on the 26th day after application, and 99% on the 36th day. On the 56th day, only very low content could be detected in the samples with the concentration of 50 rag. L-1 and 100 rag. L-1 and no forehlorfenuron could be detected on the 66th day. Thus, the safe periods for each concentration mentioned above were 18 days, 22 days, 27 days, 31 days and 34 days, respectively. [Conclusion]Due to the long duration of kiwifruit development period, FRC were lower than the national standard for MRL of 0.05 mg. L-1 at fruit mature stae, there was no safety risk with low concentration of forchlorfenuron treatment.