Separation and identification of photodegradation products of benzoic acid by capillary zone electrophoresis

A capillary zone electrophoresis (CZE) method was developed for separation and identification of photodegradation products of benzoic acid under irradiation at a wavelength of 300 nm. Parameters such as run buffer, applied voltage and injection time were optimized for the separation of benzoic acid and its photodegradation products. Linearity, limit of detection, and repeatability of migration time as well as peak area of the method were examined. Four reaction products, including salicylic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid and 3,4-dihydroxybenzoic acid have been separated and identified by spiking the known compounds into the irradiated samples using the CZE method developed. The confirmation of the reaction products is one of the key steps for proposing the possible reaction mechanisms involved in the photodegradation of benzoic acid.