Figure 5. Differential pulse voltammograms (A) obtained under optimized conditions in 0.1 mol L1 phosphate buffer (pH 2.5) solution containing (a) 0.0, (b) 5.0 107, (c) 1.5 106, (d) 3.5 106, (e) 7.4106, (f) 1.5105, (g) 3.1105, and (h) 6.2105 mol L1 of GA. (B) Analytical curve.