Analytical Sciences

Photochemical Spectrofluorometric Determination of 2,6-Dimethylphenol Based on Monitoring Its Photo-Degradation Intermediate with TiO₂ as a Catalyst

Wanhong MA, Zhihong LIU and Ruxiu CAI *

Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China

A novel spectrofluorometric method for the determination of 2,6-dimethylphenol has been developed. It is based on detecting a fluorophore intermediate produced in the course of 2,6-dimethylphenol photo-degradation with TiO₂ as a catalyst. A quartz glass reactor containing the required amount of analyte, buffer and TiO₂ is irradiated with UV light (<380 nm). The formed intermediate is detectable with fluorescence and UV absorption. What is more, the fluorescence intensity of the intermediate is dramatically enhanced when extracted into the CHCl₃ phase. A linear calibration graph was obtained over a 2,6-dimethylphenol concentration ranging from 0.002 µg ml^-1 to 0.1 µg ml^-1 with a detection limit of 0.0008 µg ml^-1. Other phenolic compounds as well as those common inorganic ions do not interfere. The kinetics of the photo-degradation reaction, which followed a successive first-order reaction kinetic model, were studied using an error-compensated algorithm. (Keywords: Photochemical fluorescent method, photo-degradation, semiconductor TiO₂, 2,6-dimethylphenol, kinetics)

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