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7958777 
Journal Article 
A sepiolite-based formulation for slow release of the herbicide mesotrione 
del Carmen Galan-Jimenez, M; Morillo, E; Bonnemoy, F; Mallet, C; Undabeytia, T 
2020 
Yes 
Applied Clay Science
ISSN: 0169-1317 
189 
English 
WOS:000529327300028 
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. 2020 Elsevier B.V. 
Nanoformulation; Sepiolite; Cationic surfactant; Ecotoxicity; Field application