Carbon dots (CDs) with different doping elements were successfully synthesized via a simple hydrothermal strategy. 3-amino-4-chlorophenylboronic acid, 3-aminobenzeneboronic acid, aniline, and benzene were used as precursors, respectively. The B/N co-doping CDs (BNCDs) derived from 3-aminobenzeneboronic acid show brightest fluorescence among the CDs products with quantum yield at 0.15. The fluorescence of BNCDs exhibits good photostability and excitation-independent emission behavior. The bright blue emission of BNCDs can be quenched by serine, which is a kind of neutral aliphatic amino acid containing hyroxyl groups with polarity. It is possibly due to the molecular collision between excited state of BNCDs and the ground state of serine. BNCDs can be served as fluorophore probe for the assay of serine based on the efficient quenching effect. The approach for the determination of serine shows a high sensitivity with a detection limit at 0.14 nM, which is lower than those of previous works. Furthermore, the present BNCDs system can be employed to monitor serine in real food and biological samples. The strategy may be a potential way for the application in food safety and biomedicine fields.
Keywords: Carbon dots; Human serum; N/B co-doping; Serine; Soy milk.