Indirect Differential Pulse Voltammetric Determination of Aluminum by a Pyrocatechol Violet-Modified Electrode

ABSTRACT

A Pyrocatechol Violet (PCV) modified electrode for the voltammetric determination of aluminum is reported. The modified electrode is simply prepared by dip-coating a pyrolytic graphite electrode in a NaAc-HAc buffer solution of PCV. Optimum experimental conditions for aluminum determination include a 0.2 mol/L NaAc-HAc buffer solution of pH 4.8, a PCV concentration of 0.02 mol/L used to modify the electrode and the use of differential-pulse mode for measurement. The peak currents of differential pulse voltammograms (DPV) decrease with the addition of Al into the buffer solution while the peak potentials remain the same. The decreasing value of peak current ▵i_p is linear with Al concentration in the range of 1x10⁻⁸ to 1x10⁻⁷ mol/L and 1x10⁻⁷ to 1x10⁻⁶ mol/L. The detection limit is 5x10⁻⁹ mol/L and the relative standard deviation for 4x10⁻⁸ mol/L Al is 2.9% (n=8). The stability of this electrode is satisfactory. No serious interference is found. This method has been applied to determine Al in drinking water samples.

Keywords::

• pyrocatechol violet
• aluminum
• chemically modified electrode
• differential pulse voltammetry
• indirect determination
• drinking water