Hydroxyl Radicals quantification by UV spectrophotometry

Hydroxilation of aromatic compounds is an oxidative process that has been employed as indirect method to quantify the produced hydroxyl radicals during an advanced oxidation process (●OH). This is usually complicated by the radical high reactivity and short life time and therefore a scavenging agent such as salicylic acid is commonly employed. This usually implies a rather sophisticated analytical method such as chromatography. In this work, however, a relatively simple and low cost method is proposed to achieve the aforementioned objective. This method is based on UV-Vis spectrophotometry and was employed to quantify the hydroxyl radicals produced during the electrochemical oxidation of water when employing a platinum anode in a galvanostatic type process. Salicylic acid was employed as ●OH scavenger. The concentration of the hydroxilated resulting products, 2,3-dihidroxybenzoic Acid and 2,5-dihydroxibenzoic Acid, was determined by UV-Vis Spectroscopy and utilized to quantify the hydroxyl radicals. In addition, mineralization was followed by Chemical Oxygen Demmand measurements.