Khay Sathya, Abd El-Aty A M, Cho Soon-Kil, Choi Jeong-Heui, Mamun M I R, Goudah Ayman, Shin Ho-Chul, Shim Jae-Han
Natural Products Chemistry Laboratory, Institute of Agricultural Science and Technology, College of Agriculture and Life Science, Chonnam National University, 300 Yong-Bong Dong, Buk-Ku, Gwangju 500-757, Republic of Korea.
Biomed Chromatogr. 2008 Jun;22(6):581-9. doi: 10.1002/bmc.972.
This study was undertaken to investigate whether an additional column clean-up procedure can affect the accuracy of an analytical method developed for the determination of imidacloprid residues in Chinese cabbage. Thereafter, the residue levels and the degradation rates of imidacloprid were investigated in experimental Chinese cabbage plots after treatment with two different commercial formulations: emulsifiable concentrate (EC) and wettable powder (WP). The analyte was determined using high-performance liquid chromatography-ultraviolet detection (HPLC-UVD) and confirmed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) in the select ion-monitoring mode. The mean recoveries ranged from 75.34 to 98.00% and 96.95 to 100.97%, with relative standard deviations of 0.86-4.14 and 1.22-3.52%, in samples treated with and without additional column clean-up procedures, respectively. The minimum detectable amount of imidacloprid was 4 ng, while the limits of detection and quantitation were 0.2 and 0.5 ppm, respectively. The degradation of pesticide was monitored throughout a period of 13 days under greenhouse conditions. Although the behaviors of the EC and WP formulations appear to be similar, the absolute residue levels obtained with EC and WP treatments differed slightly. When imidacloprid formulations were applied (as foliar treatments) according to the recommended rate, the final residues (13 days post-treatment) in Chinese cabbage were much lower than the maximum residue limit (MRL = 3.5 ppm) established by the Korean Food and Drug Administration. Taken together, our study suggests that the analysis of imidacloprid can be performed without an additional column clean-up procedure, and the decline curve and the residue levels in Chinese cabbage could change if the same active ingredient is used in different formulations.
本研究旨在调查额外的柱净化程序是否会影响为测定大白菜中吡虫啉残留量而开发的分析方法的准确性。此后，在用两种不同商业制剂：乳油（EC）和可湿性粉剂（WP）处理后的实验大白菜地块中，研究了吡虫啉的残留水平和降解率。使用高效液相色谱 - 紫外检测（HPLC - UVD）测定分析物，并通过高效液相色谱 - 质谱（HPLC - MS）在选择离子监测模式下进行确证。在有和没有额外柱净化程序处理的样品中，平均回收率分别为75.34%至98.00%和96.95%至100.97%，相对标准偏差分别为0.86 - 4.14%和1.22 - 3.52%。吡虫啉的最低检测量为4 ng，而检测限和定量限分别为0.2和0.5 ppm。在温室条件下，对农药降解情况进行了为期13天的监测。尽管EC和WP制剂的行为似乎相似，但EC和WP处理获得的绝对残留水平略有不同。当按照推荐剂量施用吡虫啉制剂（作为叶面处理）时，大白菜中的最终残留量（处理后13天）远低于韩国食品药品管理局规定的最大残留限量（MRL = 3.5 ppm）。综上所述，我们的研究表明，吡虫啉分析无需额外的柱净化程序即可进行，并且如果在不同制剂中使用相同的活性成分，大白菜中的降解曲线和残留水平可能会发生变化。
