Spectrophotometric Determinaiton of 4- Aminoantipyrine in Aqueous solution by coupling with Diazotised phenylephrine hydrochloride

Abstract

A simple, rapid and sensitive spectrophotometeric method for the determination of trace amounts of 4-amnoantiyrine in aqueous solution is described. The method is based on a coupling reaction between 4- amino antipyrine and diazotised phenyle phrine hydrochloride to form an intense violet, water-soluble dye that is stable and has a maximum absorption at 500 nm. A graph of absorbance versus concentration shows that Beer's law is obeyed over the concentration range 1-100 µg of 4-aminoantipyrine in a final volume of 25 ml (i.e., 0.04-4 p.p.m) with a molar absorptivity of 0.4024×103 l mol-1 cm-1, a sandell sensitivity of 539.26 ×10-3 µg cm-2, a relative error -0.025 +0.028% and a relative standard deviation of 0.49-0.68% depending on the concentration. The optimum conditions for full colour development and the interference of foreign organic compounds have been investigated. The proposed method does not require either temperature control or a solvent extraction step.