Abstract
Nowadays colorimetric detection of ascorbic acid based on enzyme-mimetic materials are mostly rely on chemically synthesized materials. Although nano enzymes prepared from natural source materials have been reported, their preparation required harsh conditions or multi steps. In this work, nanocomposite materials (MCTs) based colorimetric sensor assisted with smartphone was designed for rapid and on-site ascorbic acid (AA) detection. The MCTs can catalyze the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB) resulting in a color change from colorless to a deep blue in the presence of H2O2. The optimal catalytic conditions of pH, temperature and the material dosage are 3.0, 25°C and 3.0 mg, respectively. Due to the strong reducing property of ascorbic acid, the oxidation of TMB is inhibited so that the blue color faded. Based on the above principle, colorimetric sensor integrated with smartphone RGB mode was fabricated and exhibited a good linear detection range (1–250 µM) and low detection limit of 0.218 µM for AA detection under optimal conditions. The established method can also detect ascorbic acid (AA) in six commercial beverages with good accuracy. Therefore, this study has delivered a new cost-effective approach for the precise detection of ascorbic acid (AA) with a vast potential for various applications.