Preparation of microelectrodes: comparison of polishing procedures by statistical analysis of voltammetric data

Abstract

Manual and instrumental procedures for polishing 1 and 6 pm radius platinum microdisc electrodes were compared by performing a statistical evaluation of three basic electrochemical signal characteristics measured from steady-state voltammograms for oxidation of ferrocene in acetonitrile. The three signal characteristics measured were the limiting current Ilim, the half-wave potential Ell2 and the (E3/4 -E1/4) potential difference, where E3/4 and E1/4 are the potentials at three quarters Zlim and one quarter Zlim, respectively. Fisher-Snedeckor F-test and Student's t-test statistical data are presented together with corresponding critical values for the three electrochemical parameters obtained in the manual and instrumental polishing modes. The reproducibility of all measured data is significantly improved when the electrode is polished after each experiment. The mean values of the limiting currents were significantly better using the instrumental rather than the manual polishing method. However, with respect to uncertainty of the experimental values, instrumental polishing gave the best estimates of the measured parameters; confidence intervals were very small for and (E3/4 -E1/4) potential measurements, being ltO.20 and lt0.36 mV for E1/2 values and 0.11 and 0.19 mV for (E314 -E1/4) at 1and 6 pm electrodes, respectively. The instrument designed for polishing microelectrodes is also described.

The Electrochemical Oxidation of N,N‐Diethyl‐p‐Phenylenediamine in DMF and Analytical Applications. Part I: Mechanistic Study

“…All experiments were conducted in a thermally jacketed cell maintained at 25 AE 1 8C. The microelectrodes were carefully polished prior to use, using 1.0 and 0.3 mm alumina (Buehler, USA) [41]. The microelectrodes were electrochemically calibrated prior to use to obtain an accurate measurement of electrode diameter.…”

Sonovoltammetric Elucidation of Electron Transfer Rates: The Oxidation of Dimethyl‐p‐phenylenediamine in Aqueous Solution

“…The microelectrode was carefully polished using 0.3 mm alumina (Buehler, USA) [13] before use and electrochemically calibrated to obtain an accurate measurement of the electrode diameter. This was carried out in a solution containing 2.1 mM potassium ferricyanide (D 7.6 Â 10 À6 cm 2 s…”

Biphasic Sonoelectroanalysis: Simultaneous Extraction from, and Determination of Vanillin in Food Flavoring

“…Microelectrode size was calibrated using a system of known diffusion coefficient, ferrocene in dimethyl formamide (DMF) via the Cottrell equation (Equation 2). The electrodes were polished according to the procedure of Bond et al [39] using alumina up to a grade of 0.3 mm (BAS, Indiana, US) before use. All potentials are quoted with respect to a silver wire pseudo-reference-electrode.…”