Development of synchronous fluorescence methodology for highly sensitive and simultaneous determination of three dihydroxybenzene isomers using curve fitting

Abstract

A curve fitting method based on an exponentially modified Gaussian (EMG) model-genetic algorithm was used in quantitative resolution for overlapped synchronous fluorescence spectra. The method was effective for overcoming mutual interference in the course of the multi-component quantitative analysis. In this work, a novel method is developed for the highly sensitive and simultaneous determination of three isomers of dihydroxybenzene (DHB) by synchronous fluorescence using curve fitting. The method can effectively correct the overlapping interferences of the fluorescence spectra of the three DHB isomers. Under the optimized experimental conditions, the good linear relationship between the fluorescence intensity and the concentration of catechol (o-DHB), resorcinol (m-DHB) and hydroquinone (p-DHB) was obtained in the range of 0.02–10 μg mL⁻¹, 0.01–10 μg mL⁻¹ and 0.01–10 μg mL⁻¹ with a correlation coefficient of 0.9920, 0.9990 and 0.9996, respectively. Their detection limits were 0.005, 0.003, and 0.002 μg mL⁻¹, respectively, and the recoveries were in the range of 84.0–117% with relative standard deviations of 0.3–2.9%. The proposed curve fitting–synchronous fluorescence method was rapid, simple and highly sensitive for the determination of the three DHB isomers in water samples without pre-separation. This method was validated for selectivity, sensitivity, linearity, recovery, accuracy, and precision, and was successfully applied for the monitoring of DHB isomers in environmental water fields.