Chemistry Department, College of Science, Baghdad University, Baghdad-Iraq

Abstract

A simple, rapid and sensitive spectrophotmetic method for trace determination of pyridoxine hydrochloride (PYR) in aqueous solution and in pharmaceutical preparations is described. The method is based on the oxidative coupling reaction of the intended compound with p-aminophenol (PAP) to form an intense purpule, water soluble dye that is stable and shows maximum absorption at 534 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 50-1000 g of PYR in a final volume of 25 mL (i.e. 2-40 ppm), with a molar absorbtivity 2.138×103 L.mol-1.cm-1 , a sandell’s sensitivity of 0.0962 g.cm-2 a relative standard deviation of 0.519-2.383  depending on the concentration of PYR. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of PYR in dosage forms.