MnO2 nanoparticles mediated colorimetric turn-off determination of ascorbic acid
Ascorbic acid (AA) is an esstential micronutrient in human body and participates in vital processes. It can only be supplemented by external intake, making it a significance of determination of AA in food or beverages. In the present work, a MnO2 nanoprticles (MnO2 NPs) based turn-off colorimetry was established for AA determination on the basis of AA-stimulated inhibition of catalytic oxidation. MnO2 NPs were synthesized through a biotemplating method and displayed effective catalytic oxidation activity for oxidatioin of TMB, triggering a chromogenic reaction. Interestingly, the introduction of AA induced the decomposition of MnO2 NPs and as a concequence decreased the colour. Therefore, a sensitive and selective turn-off colorimetry for AA detection was established and satisfactory linear range of 0.5-30 μM with detection limit of 0.28 μM were obtained. This MnO2 NPs-based method was activated via a novel sensing priciple, complementing and facilitating the colorimetry for AA.