CHEMICALLY MODIFIED ELECTRODES FOR THE DETERMINATION OF SULFHYDRYL COMPOUNDS

Under neutral conditions, the electrocatalytic oxidation of sulphydryl compounds at rotating graphite electrodes modified with tetracyano-p-quinodimethane, tetrathiafulvalene and 1,1'-dimethylferrocene proceeds at potentials higher than -0.1 V vs. SCE. The sensitivity of the electrodes depends on the nature of both the modifier and the sulphydryl compounds, and in 0.1 M potassium phosphate buffer solution (pH 7) it reaches 0.16 A 1 mol-1 cm-2. The electrode sensitivity is higher in a weakly alkaline medium. The sensitivity is only slightly dependent on the electrode rotation speed.