Medical brain notes 35

  Voltammetric Measurements Although   early   voltammetric   methods   relied   on   the   use   of   only   two electrodes,   modern   voltammetry   makes   use   of   a   three-electrode   po-tentiostat,   such   as   that   shown   in   Figure   11.4.   A   time-dependent   po- tential   excitation   signal   is   applied   to   the   working   electrode,   chang-  ing   its   potential   relative   to   the   fixed   potential   of   the   reference  electrode.   The   resulting   current   between   the   working   and   auxiliary electrodes   is   measured.   The   auxiliary   electrode   is   generally   a   plat- inum   wire,   and   ...

  Current in Voltammetry When   an   analyte   is   oxidized   at   the   working   electrode,   a   current   passes   electrons  through   the   external   electric   circuitry   to   the   auxiliary   electrode,   where   reduc-  tion   of   the   solvent   or   other   components   of   the   solution   matrix   occurs.   Reducing  an   analyte   at   the   working   electrode   requires   a   source   of   electrons,   generating   a  current   that   flows   from   the   auxiliary   electrode   to   the   cathode.   In   either   case,   a  current   resulting   from   redox   reactions   at   the   working   and   au...