The accumulation and dissipation patterns of the aquatic herbicide fluridone, l-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4( 1H)-pyridinone, and its major degradation products have been determined in 40 pond and lake experiments in the United States, Panama, and Canada. The average bioconcentration factor for the total residue of fluridone plus a single major metabolite, l-methyl-3-(4-hydroxyphenyl)-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone, in several fish species was 1.33, 7.38, and 6.08 in edible tissue, inedible tissue, and whole body, respectively. Fluridone dissipated with an average half-life of 20 days in pond water and 3 months in pond hydrosoil. The treatment of small areas (0.8-4.0 ha) of large lakes resulted in more rapid dissipation due to dispersal of fluridone into the surrounding untreated water. Little or no carry-over of residues occurred prior to annual retreatments of the ponds. Mathematical models were evaluated for relating the half-life of fluridone in pond water to physical and chemical properties of the water. Fluridone, l-methyl-3-phenyl-5-[3-(trifluoromethyl)-phenyl]-4(1H)-pyridinone (I), is the active ingredient in 0 0 0 0

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

A method is described for the determination of the naturally derived insect control agent spinosad in cottonseed and cottonseed processed commodities (meal, hulls, crude oil, refined oil, and soapstock). The method was validated over the concentration range 0.01−0.1 μg/g, with a limit of quantitation of 0.01 μg/g and a limit of detection of 0.003 μg/g. Residues of the active ingredients in spinosad (spinosyns A and D) were extracted from samples with appropriate organic solvents. The extracting solvents were hexane for cottonseed oil, methylene chloride for soapstock, and 60% hexane/40% acetone for cottonseed, meal, or hulls. An aliquot of the extract was purified by liquid−liquid partitioning and silica solid phase extraction. Spinosyns A and D were determined simultaneously in the purified extracts by reversed-phase high-performance liquid chromatography with ultraviolet detection at 250 nm. Confirmation of residue identity was accomplished by reinjecting the same final solution into the chromatograph under different chromatographic conditions. Keywords: Spinosad; spinosyn A; spinosyn D; cottonseed; quantitation; HPLC-UV

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.

Spinosad is an insect control agent that is derived from a naturally occurring organism and is effective on a wide variety of crops, including citrus crops. A method is described for the determination of spinosad and its metabolites in citrus crops and orange processed commodities. The method determines residues of the active ingredients (spinosyns A and D) and three minor metabolites (spinosyn B, spinosyn K, and N-demethylspinosyn D). For dried orange pulp and orange oil, the method has a limit of quantitation (LOQ) of 0.02 microg/g and a limit of detection (LOD) of 0.006 microg/g. For all other sample matrices (whole fruit, edible fruit, juice, and peel), the method has an LOQ of 0.01 microg/g and an LOD of 0.003 microg/g. The analytes are extracted from the various sample types using appropriate solvents, and the extracts are purified by liquid-liquid partitioning and/or solid-phase extraction. All five analytes are determined simultaneously in the purified extracts by reversed-phase high-performance liquid chromatography with ultraviolet detection at 250 nm.