Coupling poly-(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction to capillary electrophoresis for the determination of phenols in water samples

In the present work, a simple, selective, and sensitive method has been proposed for the determination of four phenols (catechol, resorcinol, 2,6-dimethylphenol, and 2,4,6-trinitrophenol) in water samples. The method is based on poly-(methacrylic acid-co-ethylene glycol dimethacrylate) monolith microextraction (PMME) and capillary electrophoresis-ultraviolet (CE-UV) analysis. The operation parameters including sample pH, sample flow rate, sample volume, and eluent flow rate have been studied and optimized. Under the optimal experimental conditions the limits of detection for catechol, resorcinol, 2,6-dimethylphenol, and 2,4,6-trinitrophenol based three times of standard deviations of blank by seven replicates are 0.085, 0.030, 0.159 and 0.006 μg/mL, respectively. The intra-day and inter-day relative standard deviations are less than 5.6% and 5.9%. The proposed method has been successfully applied to the determination of the four phenols in water samples and the accuracy is assessed through recovery experiments.