abstract
Multiresidue analysis of fumigants is important because of their widespread use on staple foodstuffs, such as grain. Fumigants are usually extracted from grain either by solvent extraction or by purgeand- trap techniques. In this paper, fumigant residues in wheat were "extracted" by a microwave procedure. Wheat, in gas-tight Erlenmeyer flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fumigants were determined for CH3Br PH3, CS2, and COS. Recoveries of fortified samples were >90%. Completeness of extraction was assessed from the amount of fumigant retained by the microwave-irradiated wheat. This amount, determined from both solvent extraction and from further microwave irradiation, was always small(<5℅ of the amount obtained from the initial procedure). Limits of quantitation were <1 ng/g for ChhBr, PH3, and CS2. These low limits were essentially due to the absence of interference from solvents. The microwave method is rapid and solvent-free. However, care is required in selecting the appropriate power setting. The safety implications of heating sealed flasks in microwave ovens should be noted.
Effect of pH and Irradiation Power in the Synthesis of Gold Nanoparticles by using Binahong (Anredera cordifolia) Leaves Extract