Abstract

Indirect spectrophotometric determination of some catecholamine drugs

Author(s): S.H.Ahmadi, A.M.Haji Shabani, S.Dadfarnia, Kazem Kargosha

A simple, fast and sensitive indirect spectrophotometric method is proposed for the determination of epinephrine and norepinephrine. The method is based on the oxidation of the drugs by a known excess of chromium(VI) in the presence of sulfuric acid. The residue of chromium(VI) is then reacted with 1,5-diphenylcarbazid to forma red-violet color which shows an absorptionmaximumat 542 nm. Calibration graphs are linear in the range of 0.2-3.20gml-1 for epinephrine and 0.3-3.2gml-1 for norepinephrinewith detection limits of 0.1gml-1 and 0.15gml-1 for epinephrine and norepinephrine, respectively. The relative standard deviations at the level of 1gml-1 and 2gml-1(n=10) were 1.8%and 2.1%for epinephrine and 1.2% and 2.8% for norepinephrine, respectively. The method was successfully applied to the determination of these catecholamines in pharmaceutical preparations.