A carbon paste electrode chemically modified with multiwall nanotubes and ethynylferrocene (ETFc) was used as a selective and sensitive electrochemical sensor for the determination of minor amounts of N-acetylcysteine (N-AC) in the presence of a high concentration of tryptophan (Trp). Square wave voltammetry (SWV) of N-AC at the modified electrode exhibited linear dynamic range with a detection limit (3 s) of 0.08 μmolL−1. The separations of anodic peak potentials of N-AC and Trp reached 400 mV using SWV. With good selectivity and sensitivity, the present method provides a simple method for selective detection of N-AC in real samples such as drug and urine.
