吡唑醚菌酯、氰霜唑在葡萄中的残留及消解规律研究

Residue and decline dynamics of pyraclostrobin and cyazofamid in grape

中文关键词:  吡唑醚菌酯  氰霜唑  代谢物  葡萄  残留消解  安全间隔期

英文关键词:pyraclostrobin  cyazofamid  metabolite  grape  decline dynamics  preharvest interval

中文摘要:

      目的 建立了液相色谱-串联质谱法同时检测葡萄中吡唑醚菌酯、氰霜唑及其代谢物4-氯-5-(4-甲苯基)-1H-咪唑-2腈(4-chloro-5-p-tolylimidazole-2-carbonitrile, CCIM)3种化合物残留的分析方法, 提出该农药在葡萄上防治霜霉病的合理使用建议。方法 开展30%吡唑醚菌酯?氰霜唑悬浮剂在河北、黑龙江等10地2018年田间试验并检测3种化合物在葡萄中的残留消解和最终残留量, 葡萄田间试验小区在霜霉病发生初期, 兑水喷雾, 用水量60 kg/亩, 施药剂量100 mg/kg, 施药2次, 施药间隔7 d, 分别在末次施药后间隔7、14、21 d采集最终残留葡萄样品, 其中4地在同一小区在末次施药后间隔2 h和5、7、14、21、28 d取残留消解葡萄样品。样品用QuEChERS方法进行前处理后, 液相色谱-串联质谱仪检测, 外标法定量。结果 吡唑醚菌酯的最小检出量(limit of detection, LOD)为1.0×10-13 g, 氰霜唑、CCIM均为1.0×10-12 g; 吡唑醚菌酯在葡萄中的实测最低检出浓度(limit of quantification, LOQ)为0.01 mg/kg, 氰霜唑、CCIM均为0.05 mg/kg。最终残留试验结果为: 末次施药后14 d, 葡萄中吡唑醚菌酯残留量为0.163~0.631 mg/kg; 氰霜唑及其代谢物残CCIM留总量为0.108~0.567 mg/kg。从残留消解试验结果来看, 吡唑醚菌酯和氰霜唑在葡萄中降解都很慢, 河北点、黑龙江点、陕西点、广西点4地的半衰期范围为14.1~24.9 d; 氰霜唑及CCIM残留总量在葡萄中4地半衰期范围为11.6~21.4 d。结论 吡唑醚菌酯和氰霜唑属于在葡萄中降解慢的化合物, 根据GB 2763-2019《食品安全国家标准 食品中农药最大残留限量》中规定吡唑醚菌酯在葡萄上的最高残留限量(maximum residue limit, MRL)值为2 mg/kg, 氰霜唑及其代谢物CCIM之和在葡萄上的MRL值为1 mg/kg, 建议30%吡唑醚菌酯?氰霜唑悬浮剂用于葡萄防治霜霉病, 施药剂量75～100 mg/kg, 最多施药2次, 施药间隔7 d, 安全间隔期14 d。

英文摘要:

      Objective To establish an analysis method for the determination of pyraclostrobin, cyazofamid and its metabolism 4-Chloro-5-(4-tolyl)-1H-imidazole-2-carbonitrile (CCIM) in grape at the same time by liquid chromatography tandem mass spectrometry, and a reasonable suggestion was building for the prevention and control of grape downy mildew diseases. Methods An field experiment with 30% pyraclostrobin·cyazofamid SC(suspending solution) in grape was launched in ten points in Hebei, Heilongjiang etc in 2018, then final residue and dissipation dynamics of 3 kinds of chemical compounds in grape were determined, the grapes in experiment was spraied with 60 kg/mu water at 100 mg/kg dosage each for a total of 2 times with 7 days interval, then picked up in the interval to harvest in 7, 14, 21 days following last spraying application, among which 4 samples were taken from the same plot at the interval of 2 hours and 5, 7, 14, 21, 28 days after the last application. Samples were extracted and purified using QuEChERS, then detected by high performance liquid chromatography-tandem mass spectrometry(HPLC–MS/MS), calculated by external standard method. Results The limit of detection(LOD)of pyraclostrobin was 1.0×10-13 g, cyazofamid and CCIM were same with 1.0×10-12 g; the limit of quantification (LOQ)of pyraclostrobin in grape was 0.01 mg/kg, cyazofamid and CCIM were same with 0.05 mg/kg. The ultimate residues of pyraclostrobin were ranged from 0.163-0.631 mg/kg, and sum of cyazofamid and its metabolite CCIM were 0.108-0.567 mg/kg in grape 14 days after the last treatment. According to the results of residue digestion test, the degradation of pyraclostrobin and cyazofamid in grape was very slow. Decline dynamics of pyraclostrobin and sum of cyazofamid with CCIM in Hebei, Heilongjiang, Shanxi, Guangxi showed that the half-life values(T1/2)were 14.124.9 d and 11.621.4 d. Conclusion Pyraclostrobin and cyazofamid are declined slowly in grape. The maximum residue limit in grape of pyraclostrobin and sum of cyazofamid with CCIM are 2 mg/kg, 1 mg/kg respectively according to GB 2763-2019 National food safety standard-Maximum residue limits for pesticides in food, so we suggest that 30% pyraclostrobin·cyazofamid SC is launched to prevention and control of downy mildew diseases in grape with 75100 mg/kg dosage each for a total of 2 times at most with 7 d interval, the preharvest interval is 14 d.