Research Information System
Sensors and Actuators A: Physical, vol.380, 2024 (SCI-Expanded)
Ascorbic acid is a key player in the human body, pharmaceutical industry, and food industry. It is involved in many physiological processes, and its deficiency or excess amount is linked to many pathological conditions, which makes it essential to monitor its concentration. In the current work, graphitic carbon nitride (g-C3N4) and manganese oxide-doped graphitic carbon nitride (g-C3N4@MnO2) were synthesized through the pyrolysis process. Various characterization techniques, including spectroscopic, diffraction, thermal, and imaging methods, were employed to analyse the material's structural, compositional, and morphological properties. The surface chemical state of the material through X-ray photoelectron spectroscopy confirmed that manganese was present in its tetravalent state, anchoring with nitrogen in the two-dimensional g-C3N4. The synthesized g-C3N4@MnO2 demonstrated intrinsic peroxidase-like activity visualized through the naked eye by the transformation of 3,3′,5,5′-tetramethylbenzidine (TMB) to oxiTMB and confirmed through a UV-Vis spectrophotometer. The detection of ascorbic acid was performed through the peroxidase inhibitory action of the analyte through a chromogenic substrate, which reduced the oxiTMB to a colorless form. Under the optimized conditions, the sensor system was able to detect the analyte in the linear range of 1–80 µM with a 0.16 μM LOD, 0.53 µM LOQ, and an R2 value of 0.9982. The sensor system, along with its sensitivity and linearity, was very selective in the presence of various potential interfering species. The sensor was successfully employed for the sensing of ascorbic acid in real samples with excellent reproducibility. The proposed sensor can be used in diagnosis, pharmaceutical applications, and the food industry.