除虫脲在荔枝上残留及安全评价

【目的】对除虫脲在荔枝上的安全性进行评价,为该药在荔枝上的合理使用提供科学依据。【方法】通过建立除虫脲在荔枝全果和果肉的前处理方法和液相色谱—二级管阵列紫外检测器的仪器方法,对除虫脲进行定量分析;通过两年(2013~2014年)两地(广东、广西)的残留试验,研究除虫脲在荔枝上的残留及消解动态。【结果】除虫脲在荔枝果肉和全果上平均回收率分别为84.1%~84.8%和82.7%~84.9%,相对标准偏差分别为2.9%~4.3%和3.2%~4.2%,最小检出量为5×10~(-10) g,在荔枝全果和果肉上的最低检测浓度均为0.01 mg/kg。除虫脲在荔枝上的消解半衰期为3.5~4.9 d;以125.0~187.5 mg/kg剂量、施用3~4次,采收间隔期为7和10 d时,荔枝果肉上的残留量均小于0.01 mg/kg,全果上的残留量分别为0.05~0.23和0.01~0.05 mg/kg。【结论】除虫脲在荔枝上防治荔枝蒂蛀虫时施用剂量以125.0mg/kg为宜,施药次数3次,安全间隔期10 d。

Residue and safety evaluation of diflubenzuron in litchi

Objective]Safety of diflubenzuron in litchi was evaluated, in order to provide a scientific basis for ratio-nal use of diflubenzuron in litchi production . Method]An effective method was developed for quantitative analysis of diflubenzuron by HPLC-PDA(high performance liquid chromatography with photo-diode array) in whole fruit and flesh of litchi. Terminal residue and degradation dynamics of diflubenzuron in litchi were studied in Guangdong and Guangxi during 2013-2014. Result]Results showed that, spiked recoveries of diflubenzuron in whole fruit and flesh of litchi were 84.1%-84.8% and 82.7%-84.9%, respectively, with relative standard deviations of 2.9%-4.3% and 3.2%-4.2%. Limit of detection(LOD) was 5×10-10 g, and limit of quantification(LOQ) was 0.01 mg/kg in whole fruit and flesh. Half life of di-flubenzuron in litchi was 3.5-4.9 d. Furthermore, terminal residues of diflubenzuron in flesh were less than 0.01 mg/kg, terminal residues of diflubenzuron in whole litchi were 0.05-0.23 and 0.01-0.05 mg/kg, respectively, when spraying 125.0-187.5 mg/kg diflubenzuron three or four times, and pre-harvest interval was 7 or 10 days. Conclusion]Recom-mended dosage of diflubenzuron is 125.0 mg/kg for prevention and control of Conopomorpha sinensis Bladley by spraying three times at pre-harvest interval of 10 days.