Boron doped carbon dots as a multifunctional fluorescent probe for sorbate and vitamin B12

Boron doped carbon dots (B-CD) were synthesized by a one-step hydrothermal method using phenylboronic acid as the starting material. They have an average size of about 3.3nm, with excitation/emission wavelength of 247/323nm and a quantum yield of 12%. The B-CD is shown to be viable fluorescent probe for sorbate (PS) and vitamin B12 (VB12). The fluorescence (FL) of the B-CD is quenched in the presence of PS or VB12 mainly coming from inner filter effect (IFE), but Forster resonance energy transfer (FRET) from the B-CD (as a donor) to PS/VB12 (as an acceptor) cannot be excluded. The probe enables PS to be detected by fluorometry with a linear response in the 0.20-24M concentration range and a 6.1nM detection limit (at 3 sigma/slope). For VB12, the data are 0.20-30M and 8.0nM.