RESUMO
A linear algebra theorem like Cramer's rule was used for the analysis of a system of equations obtained from UV spectroscopy, and results were compared against those obtained from HPLC analysis. This parametrization allowed to quantify the concentration of the main intermediate products detected along the photodegradation of phenol under UV-Vis irradiation of TiO2. UV spectroscopy data for phenol, hydroquinone, and benzoquinone were analyzed using the Cramer's rule. The overlapping interference of the intermediate products in the UV spectra was corrected. It can be concluded that the Cramer's rule can be used for the parametrization of the UV absorbance data of phenol and its main intermediate products. This methodology permitted to obtain the concentration of phenol and their intermediate products by UV-visible with a high precision in comparison of HPLC. The parametrization showed a correlation coefficient of ca. 0.9775 between the phenol concentration obtained by UV spectroscopy and values obtained from HPLC analysis. In this sense, results can be considered with good precision, and accordingly, it can be concluded that the methodology is reliable, and UV-visible spectroscopy can be selected instead of HPLC in much of the experiments concerning with aqueous-phase reactions.