In this study, we constructed a new fluorescent sensing for VB12 and investigated the mechanism of vitamin B12 (VB12) quenching fluorescence of carbon dots (CDs). The fluorescence suppression is attributed to the inner filter effect (IFE) because of the overlap between UV-vis absorption spectrum of VB12 and emission/excitation spectra of CDs. This CDs-based sensor provides obvious advantages of simplicity, convenience, rapid response, high selectivity and sensitivity, which has potential application for the detection of VB12 in the medical and food industry.
