Electrochemical sensing performance of nitrogen rich zero- and two-dimensional carbon nanomaterials modified electrodes towards purines catabolism

Abstract

Electrochemical sensing of uric acid (UA) by using nitrogen-rich carbon nanomaterials such as N-doped carbon dots (N-CDs), N-doped graphene quantum dots (N-GQDs) and graphitic carbon nitride (GCN) electrodeposited on screen printed carbon electrode (SPCE) was studied. These N-rich carbon materials were prepared by reported procedures and characterized by spectroscopic, XRD and SEM techniques. They were deposited on SPCE by potentiodynamic electrodeposition from -0.2 to +1.7 V. The topographical studies by SEM reveal that the dots like morphology of both N-CDs and N-GQDs was retained on SPC substrate whereas aggregated thin sheet like structure was noticed for the electrodeposited GCN. Then, the electrochemical sensing performance of these electrodes towards UA was studied. Among the different electrodes, SPCE deposited with GCN (SPCE/GCN) shows the highest oxidation current for UA due to its larger surface area and lower charge transfer resistance. Further, SPCE/GCN was exploited to determine UA in the presence of xanthine (XA), which was commonly present in blood serum. The amperometric method was deployed to determine UA from 0.2 to 1000 µM and achieved the limit of detection (LOD) of 24.4 nM (S/N=3) and sensitivity of 12.4 µA µM−1 cm−2. The practical application of SPCE/GCN was examined by quantifying UA in human blood serum sample and the obtained result was validated with the clinical method.