College of Plant Health and Medicine, Qingdao Agricultural University, Key Laboratory of Integrated Crop Pest Management of Shandong Province, Qingdao, China.
Biomed Chromatogr. 2020 Sep;34(9):e4851. doi: 10.1002/bmc.4851. Epub 2020 Jun 25.
Winter is the key period for the control of apple diseases, and fungicides are needed to protect the trunk or main branches. Fungicide residue in apple tree bark is an important basis for the action of the pesticide, but there are no reports on analytical methods or dissipation patterns. In this work, thiophanate-methyl, carbendazim, tebuconazole and pyraclostrobin were selected as typical fungicides and a new QuEChERS-HPLC-VWD(QuEChERS extraction followed by high-performance liquid chromatography detection with a variable wavelength detector) analytical method was developed to estimate their residue kinetics in apple tree bark during the winter months. In the pretreatment step, the sorbent for the clean-up of extracts was optimized as 60 mg/ml primary secondary amine and a gradient-elution model followed by a variable wavelength detection was developed for instrumental analysis. Then this method was validated and applied to the analysis of apple tree bark samples with the linearity range of 0.010-50.00 mg/L, quantification limit range of 0.028-0.080 mg/kg and recovery range of 86.1-101.4%. The dissipation kinetics of thiophanate-methyl and pyraclostrobin could be described by the first-order and two-phase kinetics models, respectively. For carbendazim and tebuconazole, two new models were developed to describe their residue kinetics.
冬季是控制苹果树病害的关键时期，需要使用杀菌剂来保护树干或主枝。杀菌剂在苹果树树皮中的残留是农药作用的重要基础，但目前还没有关于分析方法或消解模式的报道。在这项工作中，选择了甲基硫菌灵、多菌灵、戊唑醇和吡唑醚菌酯作为典型的杀菌剂，并开发了一种新的 QuEChERS-HPLC-VWD（QuEChERS 提取后用可变波长检测器进行高效液相色谱检测）分析方法，以评估它们在冬季苹果树皮中的残留动力学。在预处理步骤中，优化了用于提取净化的吸附剂为 60mg/ml 初级/次级胺，并建立了梯度洗脱模型，随后进行了可变波长检测用于仪器分析。然后对该方法进行了验证，并应用于苹果树皮样品的分析，线性范围为 0.010-50.00mg/L，定量限范围为 0.028-0.080mg/kg，回收率范围为 86.1-101.4%。甲基硫菌灵和吡唑醚菌酯的消解动力学可以分别用一级和两相动力学模型来描述。对于多菌灵和戊唑醇，开发了两个新的模型来描述它们的残留动力学。
