Gas chromatographic determination of fenvalerate insecticide residues in processed tomato products and by-products.

The results of a 5-laboratory collaborative determination of residues of the synthetic pyrethroid insecticide fenvalerate in tomato products are presented. Tomatoes from plants treated in the field at 2-4 day intervals (13 foliar applications) were processed into chopped fresh tomatoes, canned quarters, juice, paste, and the by-product skins plus seeds. Gas chromatographic analysis of the commodities for fenvalerate showed the fresh produce to contain 0.26 ppm, and the skins plus seeds contained 1.9 ppm. Residues were barely detectable in canned peeled quarters and juice, but averaged 0.12 ppm for paste, the concentration product of juice. High residues were associated with the skin content of the product. Five laboratories using modifications of the same analytical technique obtained good collaborative agreement.