Dissipation pattern of endosulfan residue in/on tomato fruits

A field experiment was laid out with tomato cv. Kashi Anupam at the research farm of Indian Institute of Vegetable Research, Varanasi during 2002-2003. The treatments consisted of endosulfan 35 EC @ single dose 2.5 mill it, double dose 5.0 mlJlit and an untreated control. Fruit samples were collected from each replicate at 0, 3, 5, 7, 15 and 30 days after second spray and the residue levels were analyzed. From composite fruit sample (500g), a portion of sample (50 g) was blended in a high-speed blender and extracted With acetone and isopropanol (250) in 3:1. The suspension was filtered under slight vacuum through Buchner funnel overlaid with Wattman No.­ I filter paper. The aqueous phase was partitioned with n-hexane (3 x 50 ml). Aqueous phase was discarded and hexane phase was concentrated to 50 ml in a RotoryVacuum Evaporator. To this 50 ml concentrate, activated charcoal 10.5g) was added for adsorbing the pigments. Later this mixture was filtered and concentrated to dryness. The residue was dissolved in 10 ml HPLC grade n-hexane for GLC estimation.