The increase in the anodic current of DA (A1) has been
reported as a sensitive signal for the determination of the
concentration of nucleophiles such as sulfide [5] and thiols
[6], where the electrochemical potential of the resulting
addition product is very close to that of the original DA
and resulted in ambiguous voltammograms. In this study,
the voltammetric discrimination of the parent DA and
the adduct P is apparent. The peak current at C2 correlates
to the concentration of DA, therefore, the analytical performance
of peak C2 was assessed.