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.
