Simultaneous Determination of AA, DA, And UA Based on Bipolymers by Electropolymerization of Luminol And 3,4-Ethylenedioxythiophene Monomers

Simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) based on the bipolymers of polyluminol and poly(3,4-ethylenedioxythiophene) has been successfully performed. The bipolymers can be easily deposited on electrode surface by electropolymerization of luminol and 3,4-ethylenedioxythiophene in acidic aqueous solution by repeatedly cyclic voltammetry. The film formation is dependent on their electro-oxidation potential so that two electropolymerized procedures were applied to avoid the disorder of polymer chains. Polyluminol was performed in the potential range of 0.2–0.9 V while poly(3,4-ethylenedioxythiophene) was performed in the potential range of 0.3–1.2 V. It was found surface-confined and stable in various scan rate and different pH conditions. The calculated surface coverage (Γ) was 6.72×10−9 mol cm−2. AA, DA, and UA were simultaneously determined by this electrode at +0.16 V, +0.31 V, and 0.43 V, respectively. Compared with bare electrode, the bipolymers modified electrode exhibits lower over-potential and higher current response. It also shows more higher current response to AA, DA, and UA as compared with polyluminol and poly(3,4-ethylenedioxythiophene) modified electrodes. This bipolymers (polyluminol/poly(3,4-ethylenedioxythiophene)) modified electrode can be developed as an electrochemical biosensor to determine AA, DA, and UA.