Resolution of phenol, and its di-hydroxyderivative mixtures by excitation–emission fluorescence using MCR-ALS: Application to the quantitative monitoring of phenol photodegradation

The photodegradation of phenol using TiO2 as catalyst was studied and monitored by fluorescence excitation–emission matrix (EEM). Hydroquinone, catechol and resorcinol were the dihydroxyderivative intermediates although in lower concentrations than phenol. The data were analyzed using a three-way multivariate curve resolution alternating least squares method (MCR-ALS) and augmented matrices. The procedure was assessed using synthetic samples prepared with a {4,3} Simplex-lattice design that considered a representative range of analyte concentrations. The results were analyzed in terms of overall RMSEP for the overall data set. A detailed study was made of how the analytes behaved at each concentration level and how the concentration of the other species affected the process. The method was used to quantify phenol in photodegradation samples with an overall prediction error of 5.37%. The conversion values were fitted to pseudo first-order kinetics and the apparent rate constant was calculated to be −4.9 × 10−4 ± 5.2 × 10−5 min−1.