Determination of Total Antioxidant Capacity Using Thiamine as a Natural Fluorescent Probe

This work proposes a spectrofluorometric method for the determination of total antioxidant capacity (CAO) in beverage samples, based on inhibition of thiochrome formation (λex = 370 nm, λem = 440 nm); a product of thiamine (vitamin B1) oxidation from K3Fe(CN)6. In the development of the method, gallic acid (GA) was used as a reference, and inhibition of thiochrome formation (in percentage) was used as the analytical response. The selectivity of the method was evaluated using seven different compounds (gallic acid, ascorbic acid, quercetin, butylhydroxytoluene (BHT), 6-hydroxy-2,5,7,8-tetrame...