Electrochemical sensor for the detection of dopamine using carbon quantum dots/copper oxide nanocomposite modified electrode

• Fabrication of an electrochemical sensor from carbon quantum dots (CQDs) and copper oxide (CuO) nanocomposite for dopamine detection. • Characterized with UV–visible, FT-IR, EDS, XRD spectroscopy and microscopic methods such as the SEM and TEM. • The detection limit of this sensor (GCE/CQDs/CuO) determined via square wave voltammetry (SWV) showed that it is capable of detecting dopamine down to a concentration of 25.4 µM over a wide linear range (1–180 µM. • This sensor also demonstrates an outstanding reproducibility. This paper presented a facile fabrication of an electrochemical sensor from carbon quantum dots CQDs and copper oxide (CuO) nanocomposite for dopamine detection. Individual components of the sensor and the composite were characterized with UV–visible, FT-IR, EDS, XRD spectroscopy, and microscopic methods such as the SEM and TEM. The nanocomposite (CQDs/CuO) was applied for modification of glassy carbon electrode (GCE). The electroanalysis of DA at CQDs/CuO nanocomposite modified GCE showed that DA detection can best be achieved at about 0.3 V. The detection limit of this sensor (GCE/CQDs/CuO) determined via square wave voltammetry (SWV) was 25.40 µM over a wide linear range of 1–180 µM. This sensor also demonstrated outstanding reproducibility even though it has relatively low stability. The percentage recovery of dopamine from dopamine hydrochloride injection obtained with this sensor confirmed its suitability for DA detection in pharmaceutical samples and possibly some other dopamine-containing real samples.