Nitroso-R salt as a sensitive spectrophotometric reagent for the determination of vitamin C

An analytical procedure based on the reaction of nitroso-R salt with reduced iron(II) is developed for the analysis of ascorbic acid. The absorbance of the resulting green colored complex is measured at 705 nm. Beer's law is obeyed over the rang 0.2-3.0 mu g ml(-1) ascorbic acid with a molar absorptivity of 4.5 x 10(4) 1 mol(-1) cm(-1). The substances commonly found with vitamin C formulations are tolerated. Some of the marketed products of ascorbic acid were analyzed by the proposed method with satisfactory results.