The electrochemical behavior of riboflavin(RF) on glassy carbon has been investigated by using potential sweep,rotating ring_disc electrode and the measurement of differential capacitance. It is shown that a single well_behaved oxidation_reduction wave corresponding to a reversible two_electrons reaction apears in medium of pH<6,and the adsorption of RFH2 formed by electro_reduction is weak and hence its solubility is good.In medium of pH>6,there are two separating but overlapping partly oxidation_reduction waves corresponding to two_step one_electron reaction.The adsorptions of RFH and RFH2 produced by reduction reactions in medium of 6
<10 are strong and their solubilities are poor.However,in medium of pH>10,the solubilities of the adsorbed species produced by electro_reduction are good.
