AUTOMATIC PROCEDURE FOR SPECTROPHOTOMETRIC DETERMINATION OF HYDROQUINONE EMPLOYING MULTICOMMUTATION FLOW IN ANALYSIS SYSTEM

This paper describes a procedure based on multicommutation in flow analysis system for photometric determination of hydroquinone in pharmaceutical gel formulations. The procedure involves oxidation of hydroquinone by Fe (III) and subsequent reaction between the generated Fe (II) species with 1,10-phenanthroline, producing a complex detected at 510 nm. Under optimized conditions, the proposed system showed a linear response in the range between 5 to 120 µmol L-1 (r = 0.9995), a limit of detection (3σ) 0.52 µmol L-1 and a relative standard deviation (RSD) of 1.5% for a 80 µmol L-1 hydroquinone standard solution. Others profitable features such as an analytical frequency of 72 samples per hour; a reagent consumption of 0.432 and 0.117 mg 1-10-phenantroline and FeCl3.6H2O per determination, respectively; and a waste generation of 4.0 ml per determination were also achieved.