Determination of norflurazon residues in mixed crop matrices

A method for determining norflurazon residues in mixed crop matrices is described. The method included methanol Soxhlet extraction, hexane wash, addition of 10% saline, methylene chloride extraction, concentration, preparative thin layer chromatography of 10% sample aliquot, and resuspension of sample zone for gas-liquid chromatographic analysis. The lower level of electron capture detection is 0.01 ppm. Recoveries for 0.08 ppm spiked samples of cottonseed; soybean seed and foliage; peanut seed plus hulls and foliage; orange and tangerine; lemon; apple and peach; and soil are generally greater than 80%.