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.

中文翻译：

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使用QuEChERS / HPLC-VWD对苹果树皮中的甲基托布津，甲基多菌灵，戊唑醇和吡咯菌酯进行残留分析和动力学建模

冬季是控制苹果病的关键时期，需要使用杀菌剂来保护树干或主要树枝。苹果树皮中的杀菌剂残留是农药作用的重要依据，但尚无分析方法或消散模式的报道。在这项工作中，选择了甲基托布津，多菌灵，戊唑醇和吡咯菌酯作为典型的杀菌剂，并开发了一种新的QuEChERS-HPLC-VWD（QuEChERS提取，然后用可变波长检测器进行高效液相色谱检测）分析方法来估算其冬季，苹果树皮中的残留动力学。在预处理步骤中，用于提取物净化的吸附剂被优化为60 mg / ml伯仲胺，并建立了梯度洗脱模型，然后进行可变波长检测以进行仪器分析。然后对该方法进行了验证，并用于线性范围为0.010-50.00 mg / L，定量限范围为0.028-0.080 mg / kg和回收率为86.1-101.4％的苹果树皮样品的分析。一阶和两阶段动力学模型分别描述了甲基托布津和吡咯菌酯的耗散动力学。对于多菌灵和戊唑醇，开发了两个新模型来描述其残留动力学。定量极限范围为0.028–0.080 mg / kg，回收率范围为86.1–101.4％。一阶和两阶段动力学模型分别描述了甲基托布津和吡咯菌酯的耗散动力学。对于多菌灵和戊唑醇，开发了两个新模型来描述其残留动力学。定量极限范围为0.028–0.080 mg / kg，回收率范围为86.1–101.4％。一阶和两阶段动力学模型分别描述了甲基托布津和吡咯菌酯的耗散动力学。对于多菌灵和戊唑醇，开发了两个新模型来描述其残留动力学。