ELECTROCATALYTIC REDUCTION OF HEMOGLOBIN AT A CHEMICALLY-MODIFIED ELECTRODE CONTAINING RIBOFLAVIN

Chemically modified electrode (CME) exhibiting electrocatalytic respon se toward hemoglobin (Hb) is constructed by adsorbing the riboflavin m ediator onto spectroscopic graphite surface. The electron transfer bet ween the riboflavin functionality and the graphite is fast. The surfac e coverage is at most 9.6 x 10(-10) mol cm(-2). The modified electrode permits the electroreduction of hemoglobin to take place at a low pot ential corresponding to the reduction potential of the mediator molecu le. For neutral and slightly acidic solutions, this corresponds to ver y modest negative potentials (vs. Ag/AgCl). Characterization of the pe rformance of the CME is carried out. After 30 min of continuous potent ial scanning of pH 6.8, 60% of the original coverage remains for the C IME. The linear range of the calibration plot is 30-480 mu mol/L. The effect of the solution pH on the electrocatalytic activity of the CME for hemoglobin reduction is investigated. Due to its high sensitivity and durability, this CME could be used as an analytical sensor for det ecting hemoglobin in real samples.