The electrochemical character of bilirubin（BR）-M2+(M2+=Cd2+,Cu2+,Zn2+,Ca2+,Fe2+)Langmuir-Blodgett（LB）film modified glassy carbon electrode was investigated,and was compared with that of BR-LB film modified glassy carbon electrode and that of BR and M2+in solution.On BR-M2+-LB film modified glassy carbon electrodes,one anodic peak for BR-M2+ complex was observed at-679～-842mV,and the anodic peak potential of BR shifted towards to ositive from 453 mV to 477～493 mV.BR-M2+（in solution）formed BR-M2+ complex with BR on the BR-LB film modified glassy carbon electrode,at the same time,M2+permeated BR-LB film and occrred electrode reaction.The anodic peak potential of BR-M2+ complex on LB film shifted towards positive with the increasing of stability of biologic metal complex.In BR and M2+ solution,the potentials of two anodic peaks for BR（400 mV and 305 mV）was shifted positive 19～51 mV due to BR-M2+ complex forming,and this potential was effected by the ratio of BR and M2+.Moreover,a pair of symmetrical adsorption peak was appeared at nearly 0 mV,which indicated the hydrophobicity of this complex molecule was stronger than that of BR molecule.
The electrochemical behavior of mixed Langmuir-Blodgett (LB) film of bilir ubin and phosphatidyl ethanolamine on glassy carbon electrode were investigated with cyclic voltammetry and differential pulse voltammetry. The results prove th at bilirubin Langmuir-Blodgett film has a cathodic peak of +420mV in 0.2mol ·L-1 HAc-NaAc-50%EtOH(pH=5.4) solution. The peak current increases wit h the layer number of bilirubin LB film in the range of 1 to 12 layers. The resu t of the electrochemical behavior of bilirubin in ordered LB film was also compa red with that in cast film and in aqueous solution at glassy carbon electrode. W e found that bilirubin has the similar electrochemical behavior in LB film to in cast film, but different from that in aqueous solution.
