Paper Electrochemical Sensor Utilizing Nano Ag-Decorated Cu2O Nanoparticles for Ascorbic Acid Detection in Tablets

The accurate and selective detection of vitamins are very much needed in the food, and pharmaceutical industries and health care. In this study, a new sustainable disposable electrochemical platform was fabricated with nano silver/Cu₂O composite (nAg/Cu₂O) for sensing ascorbic acid (vitamin C). The modified electrode exhibited reduced resistance to charge transfer and improved electro active area. The analyte displayed excellent electrochemical activity on the surface of nAg/Cu₂O modified paper electrode and showed a concentration-dependent response between 0.05 to 500 μM with a detection limit (S/N=3), 0.04 μM. Furthermore, the anti-interference studies revealed that the nAg/Cu₂O nanocomposites have high selectivity towards ascorbic acid. Notably, the sensor based on nAg/Cu₂O showed exceptional stability and reproducibility, with a relative standard deviation for peak currents measuring approximately 7 % or less while testing for a week of time. The real-world application and analytical performance was realized by identifying ascorbic acid in commercial vitamin C tablets with satisfactory results.