Potentiometric application of boron- and phosphorus-doped glassy carbon electrodes

A comparative study was carried out of the potentiometric application of boronand phosphorus-doped and undoped glassy carbon samples prepared at the same heat treatment temperature (HTT 1000 oC). The electrochemical activities of the obtained electrode materials were investigated on the example of argentometric titrations. It was found that the electrochemical behaviour of the doped glassy carbon samples are very similar to a Sigri (undoped) glassy carbon sample (HTT 2400 oC). The experiments showed that the potentiometric response depends on the polarization mode, the nature of the sample, the pretreatment of the electrode surface, and the nature of the supporting electrolyte. The amounts of iodide, bromide, and of chloride were determined to be 1.27 mg, 0.80 mg and 0.54 mg, respectively, with a maximum relative standard deviation of less than 1.1 %. The obtained results are in good agreement with the results of comparative potentiometric titrations using a silver indicator electrode. The titration method was applied to the indirect determination of pyridoxine hydrochloride, i.e., vitamin B6.