Analytical Sciences

Dopamine Sensor Based on a Boron-Doped Diamond Electrode Modified with a Polyaniline/Au Nanocomposites in the Presence of Ascorbic Acid

Min-Jung SONG, Seung-Koo LEE, Jong-Hoon KIM, and Dae-Soon LIM

Department of Materials Science and Engineering, Korea University, 1, 5-Ga, Anam-dong, Sungbuk-ku, Seoul 136-713, Korea

A selective dopamine (DA) sensor was developed using gold nanoparticles (Au-NPs) dispersed overoxidized-polyaniline (PANI_ox) based on a boron-doped diamond (BDD) thin-film electrode. The concentration of the DA was determined using voltammetry as a non-enzymatic sensor. BDD thin film has a high signal-to-noise ratio, a long-term stability, a high sensitivity, and a good reproducibility. PANI nanocomposites were directly synthesized on the BDD electrode and overoxidized using 0.5 M H₂SO₄ solution. The overoxidized PANI film enhances selectivity and sensitivity toward DA. The Au-NPs were dispersed on the PANI nanocomposite by electrochemical deposition. The nanometer-sized Au-NPs favor the sensing of DA in the presence of ascorbic acid (AA). The combination of the PANI with the Au-NPs and the BDD electrode can create synergetic effects for the performance of the biosensor, such as a fast response time, a lower detection limit, a wider linear range, enhanced selectivity, and higher sensitivity for the determination of DA.

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