N,Cl co-doped fluorescent carbon dots as nanoprobe for detection of tartrazine in beverages.

Chemical doping with heteroatoms was employed to prepare N,Cl co-doped fluorescent carbon dots (N,Cl-FCDs) which may be designed for the detection of tartrazine. Using urea as the N source and FeCl · 6HO as the Cl source, N,Cl-FCDs were synthesized by hydrothermal method with carbon dots prepared from aloe. Compared with pure carbon dots (CDs), N,Cl-FCDs resulted in dramatic improvement in the fluorescence properties and surface physical chemical properties. The fluorescence quantum yield of the N,Cl-FCDs was as high as 60.52%. As an effective fluorescence probe for tartrazine, a good linear relationship between N,Cl-FCDs and tartrazine was constructed at the concentration range from 0.1 to 30 μM with a detection limit of 48 nM based on the mechanism of fluorescence resonance energy transfer (FRET). The proposed fluorescent probe method was successfully applied to detect tartrazine in beverages, which is expected to have a potential application in the field of food analysis.