SURFACE MODIFICATION OF GLASSY-CARBON BY RIBOFLAVIN

Flavin derivatives catalyze the oxidation-reduction reactions in biolo gical systems. All the known flavins form thermodynamically reversible systems. Hence flavins are good candidates for electron transfer medi ators. In the present investigation riboflavin (vitamin B-2) is attach ed to the surface of glassy carbon by covalent linkage. The electrode thus modified is characterized by cyclic voltammetry and impedance mea surements. From the voltammetric data the surface coverage is calculat ed to be 7.7 x 10(-9) mol/cm(2) From the data of the impedance measure ments, k degrees for the electron transfer across the modified electro de is calculated to be 2.5 s(-1) and the value is comparable to that o btained from voltammetric data. The modified electrode is tested for i ts catalytic properties by investigating the reduction of oxygen and t he oxidation of ascorbic acid.