spectrophotometric Determination of zinc in pharmaceutical preparations by using a new synthesized reagent [4,5-diphenyl-2-((1E)-(4-(1-(2-phenylhydrazono)ethyl)phenyl)diazenyl)-4H-imidazole]

Abstract

A simple , rapid, sensitive and new spectrophotometric method to estimate zinc in pharmaceutical preparations is described. The method depends on the reaction between zinc and the new synthesized reagent [4,5-diphenyl-2-((1E)-(4-(1-(2-phenylhydrazono)ethyl)phenyl)diazenyl)-4H-imidazole] (DPHEDPI ) to form a reddish-pink complex at pH 7.5 with a mole ratio (M:L)of (1:2), the complex exhibits a maximum absorbance at 520 nm with molar absorptivity coefficient (Ɛ) of 4.4*102 L.mol-1 cm-1. Beer’s law is obeyed in the range of (0.5–27) ppm for zinc with correlation coefficient of (0.9996) ,and the stability constant was found to be 1*10 12 L.mol-1. The relative standard deviation for seven replicate measurements, relative error and recovery values of this method were found to be 0.0015 % , -0.778%, and 99.22% respectively. Finally, this proposed method was applied for the determination of zinc in the zinc sulphate capsules drug and the results were compared with atomic absorption method.