SIMULTANEOUS DETERMINATION OF MESOTRIONE, S-METOLACHLOR AND TERBUTHYLAZINE IN PESTICIDE FORMULATIONS

摘要

In this study, method for simultaneous determination of three herbicides was developed and validated.Mesotrione (2-(4-methylsulfonyl-2-nitrobenzoyl)cyclohexane-1,3-dione), terbuthylazine (2-N-tert-butyt-6-chloro-4-N-ethyl-1,3,5-triazine-2,4-diamine) and s-metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(2S)-1-methoxypropan-2-yl]acetamide) are widelyused herbicides for control of broad spectrum weed species in maize. Available CIPAC methods for the determination of terbuthylazine (MT 234) imply use of gas chromatography, white for the analysis of s-metolachlor and mesotrione there is a lack of a standard method, as well of the method for their simultaneous determination.For the analysis, an Agilent Technologies 1100 Series LC system with 2orbax Eclipse XDB-C18 column (50 mm * 4.6 mm, 1.8 pm) was used. The best separation was achieved using a mobile phase acetonitrile and 1.536 H3PO4 (75/25, v/v), at a flow rate of 0.75mL/min and UV detection at 210 nm. Column temperature was 40 °C, while the injected volume was 1 pi. Separation of the peaks of the analyzed active ingredients was satisfactory, with retention times for mesotrione, terbuthylazine and s-metolachlor were0.783 min, 1.191 min and 1.583 min, respectively. Separation factor between peaks of mesotrione and terbuthylazine is 1.81, and between peaks of terbuthylazine and s-metolachlor is 1.43. Analyzed herbicides showed linear calibration with correlation factor (R2) higher than 0.993. The repeatability of the method expressed as relative standard deviation (%RSD) was 0.82%, 1.19% and 1.47%, for mesotrione, terbuthylazine and s-metolachlor, respectively. Under the selected conditions the accuracy of the method, determined from recovery experiments through standard addition procedure, ranged from 90.7-94.3%. The precision of the method was acceptable, with the RSDr lower than the RSD, calculated by the Horwitz equation.