A Simple Rapid Spectrophotometric Investigation of Diquat and its Applications

A sensitive method for the determination of widely used bipyridium herbicide diquat using sodium borohydride in spectrophotometer has been described. Diquat on reduction with sodium borohydride in basic medium give a blue colored dye with an absorbance maxima obtained at 620 nm. The method is calibrated over the concentration range of 2.6 to15 g in a final solution of volume 10 ml (0.26 1.5 ppm). Various statistical parameters ie. molar absorptivity, Sandells sensitivity, standard deviation and relative standard deviation have been calculated respectively. The method is simple, rapid, sensitive and satisfactorily applied for detection of diquat in samples of plant materials, soil, water and biological samples.