Pyrolytic Carbon Film Electrode Research Articles

A pyrolytic carbon film electrode for voltammetry: Part IV. Residual current characterization

Residual current characteristics of a recently introduced pyrolytic carbon film electrode are presented. Different voltammetric techniques have been used in sulphuric acid medium, acetate buffer of pH 4.6 and phosphate buffer of pH 6.8. Residual currents induced by the different techniques are low and correspond to capacities in the range 1.4–7 μF cm −2. The effects of sweep rate and sweep amplitude on residual current behaviour in linear potential sweep voltammetry have been investigated. Potential limits were determined (e.g. ±1350 mV were found in the phosphate buffer). The frequency dependence of the capacity was determined using ac voltammetry. The decay of residual current responses induced by potential steps were studied in the time intervals 5–15, 40–60 and 160–200 ms and fitted to a power function, kt − p , as well as to an exponential function, k×exp(− t/τ). Decays were found to fit the power function best with 0.8< p<1.0. Results are compared with data reported for other carbon electrodes.

A pyrolytic carbon film electrode for voltammetry : Part1. Preparation and General Characterization

The preparation of a pyrolytic carbon film material is described. The stationary silica tube used in the deposition process contains only the graphite substates of a suitable form and size for direct electrode mounting. The deposition conditions were studied systematically at temperatures below 1150°C. The carbon material produced exhibits favourable qualities as an electrode material. The voltammetric behaviour is exemplified with cyclic voltammetry on o-dianisidine (3,3′-dimethoxybenzidine) in 1 M H 2SO 4 and on hexacyanoferrate(II) in 2 M KCl. The results show a satisfactory combination of good electrode kinetics with small reproducible residual currents. Submicromolar levels of o-dianisidine can be determined by differential pulse voltammetry. Dopamine in 0.04 H sSO 4−0.01 M Na 2SO 4 exhibits quasi-reversible behaviour with no sever poisoning effects. Characteristic microstructural features of the carbon film material are discussed.

Comparison of the Pyrolytic Carbon Film Electrode with the Wax-Impregnated Graphite Electrode.

Comparison of the Pyrolytic Carbon Film Electrode with the Wax-Impregnated Graphite Electrode.