Determination of spinosad and its metabolites in food and environmental matrices. 1. High-performance liquid chromatography with ultraviolet detection.

Spinosad is an insect control agent that is derived from a naturally occurring soil bacterium and is effective on several classes of insects, especially Lepidoptera larvae. Spinosad is registered in many countries for use on a variety of crops, including cotton, corn, soybeans, fruits, and vegetables. Residue methods utilizing high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection have been described for determining spinosad and its metabolites in environmental and food matrices. These residue methods typically involve an extraction with organic solvents, followed by purification using liquid-liquid partitioning and/or solid phase extraction prior to measurement by HPLC-UV. The residue methods determine the active ingredients (spinosyns A and D) and up to three minor metabolites (spinosyn B, spinosyn K, and N-demethylspinosyn D). The methods have validated limits of quantitation ranging from 0.010 to 0.040 microgram/g. This paper briefly reviews the residue methodology for spinosad and metabolites in food and environmental matrices and provides a summary of method validation results for 61 different sample types, including newly published results for 37 additional crop matrices and processed commodities.