Construction of biomass carbon dots and multiple modes for precise determination of VB12

Although vitamin B12 (VB12) is an essential water-soluble vitamin for the human body, the adverse reaction by excessive use is also worth noting. Therefore, it is crucial to detect the accurate concentration of VB12. In this work, biomass-based carbon dots (BCDs) were prepared by a facile one-pot hydrothermal method from black rice and urea. Based on inner filter effect and static quenching mechanism, the BCDs suggested conspicuous sensitivity and specificity for VB12 detection. The linear ranges were 0.5-100 μM and 0-50 μM under dual fluorescence and colorimetric modes, respectively. Additionally, the obvious color change by addition of VB12 in BCDs solution ensured the feasibility of visual experiments with smartphone assistance. The portable determination system maintained exceptional operability, quick analysis and excellent precision. Combined with the outstanding performance in real samples, this study offers a novel tactic for pharmaceutical analysis based on fluorescence/colorimetric/visualization modes.