Electrochemical studies of sodium borohydride in alkaline aqueous solutions using a gold electrode

Cyclic voltammetry using a gold disk working electrode has been employed for quantifying sodium boro-hydride in alkaline aqueous media. A 6 mm diameter disk working electrode is shown to offer higher sensitivity compared to a 1 mm diameter electrode, demonstrated by the slope of the calibration curve being 38 times greater when the 6 mm electrode is used. The dynamic range is also greater with the 6 mm electrode. evidenced by the square of the correlation coefficient for regression over the same concentration range. The influence of the matrix on the calibration curves was evaluated; 2 M NaOH, 2 M NaOH + 10% NaBO2, 2 M NaOH + 20% NaBO2, 2 M NaOH + 25% NaBO2, and 25% NaBO2 in solution at pH 12 were the matrices investigated. The matrix was shown to affect the calibration curves; generally, increasing content of NaBO2 caused the slope to decrease. Cyclic voltammetry was then used to assess the stability of sodium borohydride in aqueous solutions of different compositions. (C) 2009 Elsevier Ltd. All rights reserved.