Fabrication of a polymer/mediator composite modified electrode and its application to electrochemical detection of iodate

Abstract A polymer/mediator composite modified glassy carbon electrode (GCE) is fabricated for electrochemical detection of iodate (IO 3 − ). Flavin adenine dinucleotide (FAD) is chosen as mediator for sensing iodate, and 3,4 ethylenedioxythiophene (EDOT) is chosen for entrapping FAD and forming a conducting polymeric matrix, poly(3,4 ethylenedioxythiophene) (PEDOT). The PEDOT/FAD modification layer is electrodeposited on the GCE by cyclic voltammetric (CV) method. It is noted that FAD can enhance the electrodeposition of PEDOT, and possible reasons are proposed to explain this phenomenon. The optimal cycle number for preparing the modified electrode is determined to be 9. The relationship between the formal potential of FAD and the pH value is studied. Two slopes, 60.4 and 29.2 mV per pH unit, are recorded in the ranges of 1.5 ≦ pH ≦ 8.5 and 8.5 ≦ pH ≦ 11.5, respectively. Additionally, it is found that the oxidation current of iodate increases significantly with the decrease of pH value.