Poly(β-cyclodextrin)/carbon quantum dots modified glassy carbon electrode: Preparation, characterization and simultaneous electrochemical determination of dopamine, uric acid and tryptophan

Abstract A novel poly(β-cyclodextrin) (β-CD)/carbon quantum dots (CQDs) composite based sensor was successfully fabricated on glassy carbon electrode through electrochemical polymerization. As-prepared β-CD/CQDs modified electrode was used for the simultaneous determination of dopamine (DA), uric acid (UA) and tryptophan (Trp). Electrochemical responses of as-prepared electrode were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry. In co-existence system containing DA, UA and Trp, three oxidation peaks well separated from each other and the potential separations of oxidation peaks of DA-UA and UA-Trp were respectively large up to 150 and 420 mV, owing to the synergistic effect of β-CD and CQDs. The linear amperometric responses for DA, UA and Trp were obtained in the concentration range of 4–220, 0.3–200 and 5–270 μM, respectively, with the limits of detection of 0.14, 0.01, 0.16 μM (S/N = 3) and the limits of quantification of 0.45, 0.04, 0.50 μM (S/N = 10). Moreover, as-prepared β-CD/CQDs modified electrode exhibited prominent selectivity, stability and reproducibility, which had promising application for the simultaneous determination of DA, UA and Trp.