Figure 1.

DP voltammograms of different pHs obtained for nonmodified carbon paste electrode in 0.1 M phosphate buffer (a) and biosensor with 0.1 M sodium acetate buffer (b) for cinnamon. For pH 9.0 (––––), pH 7.0 (– – –), pH 5.0 (– - –), and pH 3.0 (......).