Feasibility of thiocarbamate pesticide analysis in apples by supercritical fluid extraction and high-performance liquid chromatography.
Supercritical fluid extraction produced comparable results with liquid-solid extraction for the analysis of several thiocarbamate pesticides from apples at the 2 ppm spike level. These results were achieved with a simple one-step extraction procedure. The use of diatomaceous earth (Celite, Supelco, Inc.; Bellefonte, PA) served to increase thiocarbamate recoveries by aiding in the immobilization of the aqueous component of the apple matrix. High-performance liquid chromatography coupled with ultraviolet absorbance detection (HPLC-UV) had the most viable means of quantitation when compared with micro-HPLC-sulfur chemiluminescence detection (SCD) and gas chromatography-flame-ionization detection (GC-FID). The small injection volumes used with the micro-HPLC-SCD system made thiocarbamate detection at a spiking level of 2 ppm impossible. SCD did provide, however, valuable qualitative information about the nature of the apple coextractants.
Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg 24061.
A L
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Howard
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Braue
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Taylor
D002851:Chromatography, High Pressure Liquid; D005638:Fruit / Q000737:chemistry*; D007306:Insecticides / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet; D013859:Thiocarbamates / Q000032:analysis*
D007306:Insecticides; D010573:Pesticide Residues; D013859:Thiocarbamates