In this study, a new method for the simultaneous quantitative determination of triclopyr and aminopyralid in forage grass, hay, and soil was developed and validated using gas chromatography coupled with electron capture detector (GC-ECD). In this method, a simple and maneuverable esterification reaction was applied to convert the two acidic herbicides into their ester form with methanol. The target compounds were extracted with 1% hydrochloric acid-acetonitrile, esterified, purified by florisil solid-phase extraction cartridge, and detected in a single run by the GC-ECD. The average recoveries using this method, at different fortified levels, ranged from 80% to 104% with intra-day and inter-day RSDs in the range of 1.2–10.8% and 3.3–10.3% for both the herbicides, respectively. The LODs were below 0.02 mg/kg while the LOQs were below 0.05 mg/kg, both of which were much lower than the maximum residue limits (MRLs) of 25–700 mg/kg in pastures, as established by the USA (the code of federal regulations). The open field dissipation and residual analysis in pastures and soil were conducted with the commercial formulation at two locations. With time, both triclopyr and aminopyralid dissipated via first-order kinetics. In forage grass, both compounds degraded rapidly over the first 14- or 21-d period and at a slow rate over the remainder of experimental days. In soil, they degraded at a relatively slow rate, and dissipated steadily to below or close to the LOQ by 60-d post application. The half-lives of triclopyr were 1.4–1.8 d and 6.2–9.0 d and aminopyralid were 1.7–2.1 d and 8.2–10.6 d in terms of forage grass and soil, respectively. The terminal residue results indicated that on 7 d after the treatment, the residues of aminopyralid and triclopyr in forage grass and hay were lower than the MRLs set by the USA. This work can provide guidance on the reasonable use of these herbicides and also provide an analytical method for the determination of triclopyr and aminopyralid in pasture and soil.

在这项研究中，开发了一种同时定量测定牧草，干草和土壤中的tric虫和氨基吡啶的新方法，并使用了气相色谱-电子捕获检测器（GC-ECD）进行了验证。在这种方法中，应用了一种简单且可操作的酯化反应，以将两种酸性除草剂与甲醇转化为酯形式。用1％盐酸-乙腈萃取目标化合物，酯化后，用弗洛里西尔固相萃取柱纯化，然后通过GC-ECD单次检测。使用此方法在不同强化水平下的平均回收率介于80％至104％之间，两种除草剂的日内和日间RSD分别为1.2-10.8％和3.3-10.3％。LOD低于0.02 mg / kg，而LOQ低于0.05 mg / kg，两者均远低于美国规定的牧场最高残留限量（MRL）25–700 mg / kg（联邦法规）。在两个地方使用商业配方进行了牧场和土壤中的野外耗散和残留分析。随着时间的推移，旋毛虫和氨基吡啶都通过一级动力学消散。在饲草中，这两种化合物在最初的14或21天内迅速降解，而在其余的实验天中则以缓慢的速率降解。在土壤中，它们以相对较慢的速度降解，并在施用后60天稳定地消散至低于或接近LOQ。就草料和土壤而言，旋毛虫的半衰期分别为1.4–1.8 d和6.2–9.0 d，而氨基吡喃类的半衰期分别为1.7–2.1 d和8.2–10.6 d。最终残留结果表明，处理后第7天，饲草和干草中的氨基吡啶和毛虫残留低于美国设定的最大残留限量。这项工作可以为合理使用这些除草剂提供指导，也可以为测定牧草和土壤中的虫和氨基吡喃酮提供一种分析方法。