A Sensitive Spectrophotometric Method for the Determination of N-Trichloromethyl Thiotetrahydro Phthalimide (Captan)

摘要

A sensitive spectrophotometric method for the determination of N-trichloromethyl thiotetrahydrophthalimide (captan), a widely used pesticide at ppm level is described. The method is a modified form of Fujiwara reaction in discharging the colour obtained by adding pyridine and alkali with acetic acid followed by the addition of p-aminoacetophenone reagent resulting in the formation of an orange yellow coloured polymethine dye having absorption maxima at 495 nm. The sensitivity after this modification is increased about five times than the conventional Fujiwara reaction. Beer's law is obeyed in the range of 5-50 μg (0.5-5ppm) of captan per 10 ml of solution. The method has been sucessfully applied for the determination of captan in fruits, grains and agricultural waste water.