Spectrophotometric determination of isoproturon using p-aminoacetophenone and its application in environmental and biological samples

A simple and sensitive method for the determination of isoproturon, a widely used herbicide is described here which is based on alkaline hydrolysis of isoproturon to its corresponding primary amine followed by diazotization and coupling with p-aminoacetophenone in alkaline medium. The absorption maxima of the coloured compound formed is measured at 525 nm. Beer's law is obeyed over the concentration range of 0.5-5.0 mug in a final solution volume of 25 ml (0.02-0.2 ppm). The molar absorptivity and Sandell's sensitivity were found to be 8.6x10(5) l mol(-1) cm(-1) and 0.0002 mug cm(-2), respectively. The method has been satisfactorily applied to the determination of isoproturon in environmental and biological samples.