Application of nanocrystalline graphite-like pyrolytic carbon film electrode for determination of thiols

The quantification of some biologically important amino acids, namely cysteine, homocysteine, and N-acetylcysteine, was reported using pyrolytic carbon film (PCF) electrodes. Optimum responses were observed for the carbon films fabricated at a deposition temperature of 1100 °C (PCF1100) by chemical vapor deposition (CVD). Electro-oxidation of these sulfur-containing compounds at the PCF1100 showed well-defined signals and no electrode fouling was observed during a set of experiments. The PCF1100 electrode exhibited good resistance against interference by ascorbic acid with distinct separation from cysteine in voltammetric signals. The performance of this electrode was comparable to and in some cases even better than those observed at other unmodified carbon-based electrodes and many chemically modified electrodes in terms of detection limit, linear dynamic range, and sensitivity. Moreover, the electrode was successfully applied for the determination of cysteine in a tissue growth medium and the results proved that the sensitivity is not affected by presence of a large variety of potential interferences in this medium.