Abstract A slow release formulation (SRF) of the herbicide mesotrione (MS) [2-(4-mesyl-2-nitrobenzoyl)cyclohexane-1,3-dione] was designed for extended weed control relative to that of conventional formulations. The SRF was designed by incorporating the herbicide in micelles formed by the fatty amine ethoxylated surfactant Ethomeen T/15 (ET15) followed by their further sorption on the clay mineral sepiolite. The content of active substance (a.s.) was very high, 16.8% w.w. The surfactant per se was adsorbed by developing surface aggregates on sepiolite's surface. FTIR spectroscopy and zeta potential measurements demonstrated that electrostatic interactions were responsible of the sorption of MS by using micelles loaded with the herbicide, modifying the conformation of ET15 on sepiolite. Toxicity assays by using Microtox® tests yielded a value of IC50 for the SRF (52.6 ± 3.6 mg L−1) that was one order of magnitude higher than that reported for the commercial formulation Callisto® (1.1 ± 0.1 mg L−1). In vitro water release experiments stated that the release of MS was a controlled-diffusion process. Application of SRF and Callisto® as post-emergence in field trials of maize showed that after 10 days of treatment (DAT), the amount in the soil of the herbicide from the SRF was about two-fold higher than that of Callisto®, with a larger accumulation (42% of the total) in the upper soil layer (0–10 cm depth). No significant differences in soil accumulation at longer times and in the crop yield were observed. Consequently, the use of the designed sepiolite-based formulation significantly reduced MS leaching over the conventional formulation while maintaining the desired bioactivity for weed control.

中文翻译：

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一种用于缓释除草剂甲基磺草酮的基于海泡石的制剂

摘要 除草剂甲基磺草酮 (MS) [2-(4-甲磺酰基-2-硝基苯甲酰基)环己烷-1,3-二酮] 的缓释制剂 (SRF) 设计用于相对于常规制剂的延长杂草控制。SRF 的设计是通过将除草剂掺入由脂肪胺乙氧基化表面活性剂 Ethomeen T/15 (ET15) 形成的胶束中，然后进一步吸附在粘土矿物海泡石上。活性物质 (as) 的含量非常高，为 16.8% ww 表面活性剂本身通过在海泡石表面形成表面聚集体而被吸附。FTIR 光谱和 zeta 电位测量表明，静电相互作用是通过使用负载除草剂的胶束来改变海泡石上 ET15 构象而导致 MS 吸附的原因。使用 Microtox® 测试进行的毒性测定得出 SRF 的 IC50 值（52.6 ± 3.6 mg L-1），比商业制剂 Callisto® (1.1 ± 0.1 mg L-1) 报告的值高一个数量级。体外水释放实验表明，MS 的释放是一个受控扩散过程。SRF 和 Callisto® 作为玉米田间试验中的芽后应用表明，经过 10 天的处理 (DAT)，来自 SRF 的除草剂在土壤中的含量比 Callisto® 高约两倍，其中在上层土层（0-10 厘米深度）有更大的积累（占总量的 42%）。在较长时间的土壤积累和作物产量方面没有观察到显着差异。最后，