Sb(V) is also able to form a complex with pyrogallol. If a negative
potential is applied to the electrode during a defined time prior to
the linear scan, well defined peak is also observed for Sb(V) complex
at −0.2 V vs Ag/AgCl electrode (Fig. 1c). Due to applying of this
negative potential, the electrochemical reduction of the Sb(V)-py
to Sb(III)-py takes place and Sb(III)-py is accumulated on the electrode
surface. As it can be seen in Fig. 1c, this reduction process is
not observed, but the accumulated Sb(III)-py is reduced at −0.2 V,
and therefore the electrochemical response for Sb(V)-py is similar
to response of Sb(III)-py [19].