Trilacunary keggin type polyoxometalate-conducting polymer composites for amperometric glucose detection

Abstract

A new amperometric glucose sensor has been fabricated based on a composite film prepared by electrochemical polymerization of carbazole derivative with having free amino group in presence of the Keggin type polyoxometalate (POM) anion, (nBu4N)3[PW9O34(tBuSiOH)3]. During the electropolymerization of 3-Amino-9-ethylcarbazole (AAC) on graphite electrode, simultaneously the POM has entrapped in the produced PAAC polymer film. POM/PAAC composite film was successfully synthesized and characterized with electrochemical techniques and surface morphology analyses. Metal/organic conducting polymeric composite has been composed of positively charged PAAC based conducting polymer and negatively charged POM structures. The amperometric response of the POM/PAAC-GOx modified electrode versus varying concentrations of glucose was studied at a potential value of -0.7 V (Ag/AgCl). It was determined that the POM/PAAC composite structure with the best sensor response has the lowest oxidation potential among the composite structures prepared at different ratios. Sensitivity of the POM/PAAC based sensor platform for actual glucose detections has been calculated as 66.66µA mM-1cm-2 with a linear detection range from 0.1 to 10 mM and detection limit of 0.099 mM. The POM/PACC composite has a unique structure thanks to such advantages the multiple redox reaction, high reactivity and rapid electron transfer of POMs. Especially, as-prepared this composite displayed high electrocatalytic activity for the amperometric detection of glucose with rapid response time, good sensitivity and reproducibility, acceptable recovery and simple preparation.