Polarographic anodic oxidation wave that can be correlated to total antioxidant capacity (TAC) in Human serum corresponds to 2H(+) and 2e process. The limiting current of the wave, which is proportional to TAC, is strongly influenced by UV light intensity and irradiation time. A mechanism has been proposed to explain the effects of UV on anodic wave related to antioxidant behavior. Results show that decomposition processes follow to the excitation a transitory product at three different light intensities at 340 nm. The number of decomposition products increase with increasing light intensity. The rate of oxygen radical capture ability of the serum antioxidants might be estimated by comparing the changes of anodic wave in the absence and presence of naturally dissolved oxygen. (c) 2007 Elsevier B.V. All rights reserved.