Carbon nitride quantum dots tethered on CNTs for the electrochemical detection of dopamine and uric acid

Abstract

The precise measurement of dopamine (DA) level is of great concern, since its abnormal levels produce several physiological and pathological effects. The detection of a trace amount of DA in the presence of uric acid (UA) and ascorbic acid (AA) still remains a challenge. A zero dimensional–one dimensional (0D–1D) architecture is prepared from carbon nitride quantum dots (CNQDs) and functionalized multiwalled carbon nanotubes (f-CNT). A f-CNT network with anchored CNQDs is synthesized for the first time through a hydrothermal treatment of an aqueous solution containing –COOH functionalized CNTs and –COOH and –SO₃H functionalized carbon nitride nanosheets (CNNSs). The high electro-catalytic activity of CNQDs/f-CNT has been utilized for the selective and sensitive electrochemical detection of DA and UA. The CNQDs/f-CNT nanocomposite was used as a modifier for the glassy carbon electrode (GCE), and produces sharp distinguishable anodic peaks for DA, UA, and AA in its ternary mixture. Differential pulse voltammetry (DPV) was performed for the selective and simultaneous detection of DA and UA in the presence of 1 mM AA. The amperometric technique was also used for the detection of DA (linear range: 1 nM –350 μM, LOD: 19 nM) and UA (linear range: 1–260 μM, LOD: 0.173 μM). This nanocomposite was employed for the detection of DA and UA by spiking various concentrations of analytes in human blood serum and obtained recovery within 4% error.