Microwave-assisted extraction method for the determination of atrazine andfour organophosphorus pesticides in oranges by gas chromatography (GC)

A simple and rapid microwave assisted extraction (MAE) method is presented for the determination of atrazine and four organophosphorus pesticides (par athion-methyl, chlorpyriphos, fenamiphos and methidathion) in orange peel. The experimental variables that affect the MAE method, such as temperature, sample quantity, extraction time, nature and volume of organic solvents, w ere optimized. The MAE method was optimized using an experimental design. T he results suggest that temperature and sample quantity are statistically s ignificant factors. It was concluded that the five pesticides could be effi ciently extracted from 1.5-2.5 g of orange peel with 10 mL of hexane/aceton e (1:1) mixture at 90 degrees C in 9 min with microwave power set at 50% (4 75 W). After optimization these factors, recoveries ranged from 93 to 101% with a relative standard deviation ranging from 1 to 3%. The extracts were analyzed by gas chromatography with a nitrogen-phosphorus detector (GC-NPD) .