Determination of hydroquinone in pure form and pharmaceutical preparations using Batch and FIA-Merging Zone techniques with spectrophotometric detection


In this study, anew, rapid and sensitive batch and flow injection-merging zones spectrophotometric methods for the determination of hydroquinone in a pure material and in pharmaceutical preparation were proposed.These methods were based onthe oxidative-coupling reaction of HQ with 2,4-dinitrophenylhydazine(DNPH) in the presence of sodium periodate and sodium hydroxide to form a dark brown water slouble dye that is stable and has maximumabsorption at 530nm, graphs of absorbance versus concentration show that Beer's low is obeyed over the concentration rang of 1-40 and 3-300 µ of hydroquinone, with detection limits of 0.162 and 0.510 µ hydroquinone for batch and FIAmethods, respectively. The optimized FIAsystem is able to determine hydroquinone with a through put of83h-1.All different chemical and physical experimental parameters affecting on the development and stability of the colored productwere carefully studied and the proposed methods were successfully applied for the determination of hydroquinone in pharmaceuticalpreparations.