Optimization and Validation of the Miniaturized Solid-Liquid Extraction with Low Temperature Purification (SLE-LTP) Method for Determining Fluopyram in Sandy, Clayey and Medium-Textured Soil

Fluopyram is a fungicide which can also be used as a nematicide in agricultural areas. The Brazilian Ministry of Agriculture authorized the commercialization and use of this molecule in Brazilian agriculture in 2019, but studies involving the development of an extraction and quantification method of this compound in environmental matrices such as soil are still scarce. Therefore, the present study aimed to optimize and validate the miniaturized version of the solid-liquid extraction with low temperature purification (SLE-LTP) method for determining this compound in sandy, clayey and medium-textured soil samples. All analyzes in this study were performed by gas chromatography coupled to mass spectrometry (GC-MS). The results revealed that the analyte recovery percentages in the three soil types ranged from 86 to 114% with a relative standard deviation of less than 15%. In addition to employing smaller amounts of reagents and sample, the miniaturized SLE-LTP method was selective, precise, exact, and linear in the range from 3 to 210 μg kg-1, and reached a limit of quantification lower than 3.00 μg kg-1 for the three soil types. The extraction method was applied to 30 real samples collected in coffee growing regions, but no residue of this compound was detected in these samples.