Voltammetric behavior of I2/2I− redox system on boron-doped diamond electrode in various media and its utilization for the indirect detection of tin(II)

Abstract Simple and fast electroanalytical method for the detection of tin(II) in bronze has been developed. It is based on synergistic combination of boron-doped diamond electrode as sensitive voltammetric sensor and reaction electrochemistry. The voltammetric response is enhanced by chemical recycling of iodide after electrogeneration of iodine followed by reaction with Sn(II). The charge transfer for the oxidation of iodide to iodine on boron-doped diamond electrode was investigated and characterized in eight different electrolytes. Charge transfer coefficient (0.58 in 0.1 mol L − 1 H 3 PO 4 –0.35 in 0.1 mol L − 1 HCl), formal potential (0.65 V in 0.1 mol L − 1 HClO 4 –0.90 V in 0.1 mol L − 1 NaHCO 3 ) and standard heterogeneous rate constant (4.6 × 10 − 3  cm s − 1 for H 3 PO 4 –2.2 × 10 − 3  cm s − 1 for NaHCO 3 ) were estimated. Based on these values it was observed that the charge transfer is irreversible, but the response is suitable for the quantification of tin(II) in bronze for tire cords. The detection limit of 2.3 × 10 − 7  mol L − 1 was achieved by linear sweep voltammetry. This value is comparable with some expensive and time consuming techniques routinely used for this type of determination.