Simultaneous determination of resorcinol and hydroquinone in waste water by double-system double-wavelength fluorometry

Based on the fluorescent difference of resorcinol and hydroquinone at different acid medium,a novel method for simultaneous determination of resorcinol and hydroquinone by double-system double-wavelength fluorometry was developed.The excitation wavelength of the reaction systen is at 280 nm.The wavelength pairs for determining resorcinol and hydroquinone at pH 2(HCl) and pH 7(H2O) are 309.0 nm(pH 2.0)/358.7 nm(pH 7.0) and 329.6 nm(pH 7.0)/358.7 nm(pH 2.0),respectively.The fluorescence intensity differences obtained by both wavelength pairs are linear with the concentration of resorcinol and hydroquinone in the range of 1.0×10-8-1.0×10-5 mol/L and 1.0×10-8-5.0×10-5 mol/L,respectively.The method has been used for the determination of resorcinol and hydroquinone in the laboratory waste water with the recoveries ranging from 95.3% to 101.0% and 94.3% to 97.0%,respectively.