Determination of the Naturally Derived Insect Control Agent Spinosad and Its Metabolites in Soil, Sediment, and Water by HPLC with UV Detection

Abstract

A method is described for the determination of the naturally derived insect control agent spinosad and its metabolites in soil, sediment, and water. The method determines residues of the active ingredients in spinosad (spinosyns A and D) and two metabolites (spinosyn B and N-demethylspinosyn D). For soil and sediment, the method has a limit of quantitation of 0.01 μg/g and a limit of detection of 0.003 μg/g. For water, the method has a limit of quantitation of 0.001 μg/mL and a limit of detection of 0.0003 μg/mL. The analytes are extracted from water, soil, or sediment using appropriate solvents, and the extracts are purified by liquid−liquid partitioning and silica solid phase extraction. All four analytes are determined simultaneously in the purified extracts by reversed-phase high performance liquid chromatography with ultraviolet detection at 250 nm. Keywords: Spinosad; spinosyn A; spinosyn D; spinosad B; N-demethylspinosyn D; soil; sediment; water; quantitation; HPLC-UV