Development and Validation of a Solid-Liquid Extraction with Low Temperature Partitioning (SLE/LTP) Method for Determination of the Herbicide Indaziflam in Brazilian Soils by High Performance Liquid Chromatography (HPLC-UV/Vis)

Given the increased use of herbicides in intensive agriculture, it is essential to understand the dynamics of new products in the soil and in the wider environment, in order to avoid problems of contamination. One of the herbicides recently registered in Brazil is indaziflam (C16H20FN5). Although various analytical techniques are available for the determination of herbicides in soils, there have been few studies concerning indaziflam. In the present study, a solid-liquid extraction with low-temperature partitioning (SLE/LTP) method was developed, optimized, and validated for the identification and quantification of this herbicide in the soil by high-performance liquid chromatography with ultraviolet detection (HPLC-UV/Vis). Samples (4 g) of clayey and sandy Red-Yellow Latosol soils were conditioned with charcoal (1% w/w) obtained from the pyrolysis of sugarcane bagasse and were fortified with 2 mg L-1 of indaziflam. Extraction was performed using 4 mL of ultrapure water (pH 7.0) and 10 mL of acetonitrile (ACN)/ethyl acetate (EtOAc) in a proportion of 8.1:1.9 mL. The mixture was vortexed and then frozen at -20 °C. The supernatant was filtered, evaporated to dryness, and then recovered in 1.5 mL of ACN, prior to analysis by HPLC-UV/Vis. The recoveries of the herbicide were between 79.56 and 106.41% and the coefficients of variation were between 0.9 and 14.4%, in conformity with the parameters established by national regulatory agencies. The method provided selective, efficient, and accurate determination of indaziflam in the soils studied.