Boron-doped diamond electrode use for amperometric assay of bromide and iodide ions

The electrochemical assay of bromide and iodide ions at boron-doped diamond (BDD) electrode was investigated by cyclic voltammetry and chronoamperometry. Comparison experiments were carried out using a glassy carbon (GC) electrode. The BDD electrode exhibited well-resolved and irreversible reduction voltammograms, while the GC electrode provided only an ill-defined response. Cyclic voltammetric signals at BDD electrode for 10 mM Br- and I- were observed at 561 and 125 mV vs. SCE; the values shifted negatively for 228.7 and 187.5 mV, respectively, compared to those at GC electrode. It was also found that the peak current of Br- and I- was in direct proportion to the scan rate, which is indicative of a surface controlled reduction process. Sensitive amperometric responses for Br- and I- were obtained covering the linear ranges 0.666 μM-1 mM and 13.3 nM-1 mM, respectively, and their detection limits were 0.53 nM and 1.67 nM, respectively, under the optimum pH and applied potential. The amperometric response was very reproducible and stable with satisfactory recovery results