The chem. modified electrode (CME), which was constructed by adsorbing a new mediator cresyl fast violet onto the spectrog. graphite electrode, shows electrocatalytic activity to the reduction of Hb. In the potential range +0.2V~-0.4V the mediator cresyl fast violet behaves as two electrons reversible redox process involving two protons. In the medium of 0.2 mol譫m -3NaOAc-HOAc (pH=5.5) the surface formal potential E0' and apparent electron-transfer rate of the adsorbed mediator cresyl fast violet are -0.18V (vs. SCE) and 0.71s-1, resp. The CME shows a good stability, and a good current response of Hb. It can be used as a sensor for determing Hb in FIA of LC-EC method.

Key words: HEMOGLOBIN, CHEMICAL MODIFIED ELECTRODE, ELECTRO-CATALYSIS, GRAPHITE ELECTRODE