Characterization, Direct Electrochemistry, and Electrocatalysis of Immobilized Hemoglobin on a Platinum Nanoparticle−Didodecyldimethylammonium Bromide Composite Film

The electrochemistry of didodecyldimethylammonium bromide and polyvinylpyrrolidone-protected platinum nanoparticles was characterized with immobilized hemoglobin on a glassy carbon electrode. Platinum nanoparticles with an average diameter of 3 nm were prepared and showed excellent stability with polyvinylpyrrolidone. Hemoglobin/polyvinylpyrrolidone–platinum/didodecyldimethylammonium bromide films on glassy carbon allowed more rapid, direct electron transfer between the protein and electrode than on an unmodified electrode. The hemoglobin/polyvinylpyrrolidone–platinum/didodecyldimethylammonium bromide/glassy carbon electrode was reversible with better sensitivity than hemoglobin/didodecyldimethylammonium bromide or hemoglobin/polyvinylpyrrolidone-platinum film electrodes. The modified electrode offered good sensitivity for oxygen and hydrogen peroxide, as well as long-term stability, good reproducibility, and excellent selectivity. The electrode response was linear with hydrogen peroxide concentrations from 0.020 to 0.240 µmol/L with a detection limit of 0.010 µmol/L. The apparent Michaelis-Menten constant was 0.107 mmol/L.