GQDs Incorporated CoPc Nanorods for Electrochemical Detection of Dopamine and Uric Acid

Dopamine (DA) and uric acid (UA) are biomolecules of great consideration that coexist in human body. It is essential and challenging to detect them simultaneously with high sensitivity. This paper reports a novel electrochemical biosensor based on the nanocomposites of cobalt phthalocyanine (CoPc) anchored with graphene quantum dots (GQDs) for DA and UA detection. The GQDs incorporation on CoPc nanorods with partial end stretching significantly enhances the electrocatalytic activity and promotes the electron transfer rate. Low detection limits of 21 nm for DA and 145 nm for UA have been successfully achieved for the fabricated CoPc/GQDs biosensor. The density-functional theory proves the enhanced conductivity of CoPc/GQDs and the biomolecule's interaction with the electrode surface. Furthermore, the proposed sensor shows remarkable reproducibility, repeatability, and stability. The fabricated sensor is applied for the simultaneous detections of DA and UA in human urine samples. The excellent performance suggests that the CoPc/GQDs could be a promising and potential candidate for electrochemical sensors to detect DA and UA selectively.