Simultaneous detection of iodine and iodide on boron doped diamond electrodes

Individual and simultaneous electrochemical detection of iodide and iodine has been performed via cyclic voltammetry on boron doped diamond (BDD) electrodes in a 1 M NaClO4 (pH 8) solution, representative of typical environmental water conditions. It is feasible to compute accurate calibration curve for both compounds using cyclic voltammetry measurements by determining the peak current intensities as a function of the concentration. A lower detection limit of about 20 μM was obtained for iodide and 10 μM for iodine. Based on the comparison between the peak current intensities reported during the oxidation of KI, it is probable that iodide (I−) is first oxidized in a single step to yield iodine (I2). The latter is further oxidized to obtain IO3−. This technique, however, did not allow for a reasonably accurate detection of iodate (IO3−) on a BDD electrode.

► Accurate calibration curves can be constructed for iodine and iodide using cyclic voltammetry. ► I− is first oxidized to iodine, which is further oxidized to iodate (IO3−). ► It is possible to calculate the concentration of iodine in the mixture with reasonable accuracy. ► Reproducibility of the results by glassy carbon electrodes was lower with respect to BDD. ► Iodate is not further oxidized to periodate on BDD electrode.