Quantitative determination of resorcinol in presence of phenol

A simple and accurate method for the quantitative determination of resorcinol in the presence of phenol is reported. The method is based on the formation of indophenol by reacting resorcinol with 2, 6-dibromoquinone-4-chlorimide. The concentration of indophenol can be measured spectrophotometrically. This method is recommended for the determination of resorcinol in resorcinol-phenol-boric acid solution and carbol-fuchsin solution. The decomposition products of resorcinol and phenol, e.g., colored quinones, do not interfere with the assay procedure.