The kinetics of the removal of beta-lactoglobulin (beta-Lg) adsorbed on a stainless steel surface by H2O2-electrolysis treatment, in which hydroxyl radicals (OHs) generated by the electrolysis of hydrogen peroxide decompose the substances adhering on the surface, was investigated. The rate of removal of the adsorbed beta-Lg from the stainless steel surface during the treatment was monitored in situ by ellipsometry. The dependencies of the removal rate on the H2O2 concentration, the electric potential applied to the surface, and the supporting electrolyte concentration were examined and the results were compared with those obtained for the treatment of a titanium surface. Differences in the removal rates of the protein from the stainless steel and titanium surfaces are discussed with respect to differences in the nature of the interaction between the protein and the surface. The atomic compositions of the stainless steel surface before and after treatment were analyzed by Auger electron spectroscopy, and the stainless steel surface was found not to be affected by the H2O2-electrolysis treatment. The influences of various coexisting materials on removal characteristics during the H2O2-electrolysis treatment were also investigated. The difference between the effect of coexisting substances on the decomposition rate for the radical reaction in the H2O2-electrolysis treatment and that for the well-known UV-H2O2 treatment in bulk solution is discussed. (C) 2003 Elsevier Inc. All rights reserved.