Elegant method for the determination of nitrite and nitrate in environmental samples

A simple and sensitive method for the spectrophotometric determination of nitrite and nitrate is described. The method is based on azo coupling reaction, where the diazotized dapsone is coupled with resorcinol in alkaline medium. The azo dye formed is stable for 24 h and has an absorption maximum at 510 nm. The system obeys Beer's law over the range 0.02 - 0.8 mu g mL super(-1) of nitrite. The molar absorptivity of the coupled product is found to be 5.4 x 10 super(4) L mol super(-1) cm super(-1). The interference effects of various species have been reported. The method has been found to be applicable for the determination of nitrite and nitrate in various water, soil and vegetable samples