A novel modified electrode was constructed by casting α-cyclodextrin-incorporated carbon nanotubes on graphite surface to form a functionalized interfacial layer. The modified electrode exhibits an excellent electrocatalytic activity for the oxidation of L-cysteine. The currents(measured by different pulse voltammetric techniques) increase linearly with the increase of the concentration of L-cysteine in the range from 1×10 -6 to 2×10 -3 mol/L. The detection limit is 2×10 -7 mol/L. The modified electrode has the best properties of the two components of the system, such as the electrocatalytic properties of carbon nanotubes and the molecular recognition and accumulation abilities of α-cyclodextrin. The result demonstrates that it has a good stability and reproducibility and is available in the detection of L-cysteine in urine.
Nanocrystalline TiO 2 particles film has been considered as an eminent matrix for the immobilization of biomolecules due to its high biocompatiability, high protein loading and special binding ability. The direct electron transfer process of hemoglobin was achieved at nanosized TiO 2 film electrode, in which a well defined redox peak of hemoglobin could be observed. However, this peak decreased with the presence of NO, indicating the electrochemical activity of hemoglobin was inhibited by the interation between hemoglobin and NO. While the further evidence revealed that such activity could be recovered after releasing NO from hemoglobin with electrochemical oxidation method.
