Carbon Quantum Dot-Modified Carbon Paste Electrode-Based Sensor for Selective and Sensitive Determination of...

A carbon quantum dot-based carbon paste electrode was fabricated and used for the determination of adrenaline (AD) at the nanomolar level. This fabricated electrode exhibited tremendous electrocatalytic activity for the oxidation of adrenaline in supporting electrolyte (PBS of pH 7.4). Scan rate variation studies with the modified electrode revealed that the overall electrode process was controlled by a diffusion process. A lower detection limit of 6 nM was achieved by chronoamperometry. Interference by biological molecules such as serotonin (5-HT) and ascorbic acid (AA) in the electrochemical oxidation of AD on the fabricated electrode was tested. It was observed that with the modified electrode, the selective determination of AD was possible. Further, with the fabricated electrode, simultaneous analysis of AA, AD, and 5-HT was performed, and it was observed that the overlapped peaks of these analytes on the naked electrode were well resolved into three peaks on the modified electrode. Along with decent sensitivity and selectivity, the electrode also showed higher stability and antifouling nature. The real-time application of the projected scheme was proven by employing the said electrode for adrenaline in adrenaline bitartrate injections.