Spectrophotometric Determination of 1- Naphthylamine by Diazotization and Coupling with 8-Hydroxyquinoline

A spectrophotometric method for the assay of micro amount of 1- naphthylamine (1-NPA) has been suggested .The method based on the reaction with nitrite ion to form the corresponding diazonium salt followed by coupling reaction in a alkali medium of sodium hydroxide with 8- hydroxyquaniline to form stable and a soluble orange azo dye. The intensity of absorbance for the resulting orange azo dye is measured at 492.5 nm and. Beers law is obeyed in the concentration range of 2.5 125 g of 1-NPA in a final volume of 25 ml, with a molar absorptivity of 2.505 104L.mol-1.cm-1, a relative error of 0.16 to + 0.65 % and a relative standard deviation of 0.37 to 0.98 %, depending on the concentration level of 1-NPA .The method has been successfully applied for the assay of 1-NPA in river water.