Sulfanilic acid assisted-synthesis of nitrogen and sulfur co-doped biomass carbon dots with visible pH response for sensing nitrofuran antibiotics

The abuse of antibiotics posed a serious threat to food security and human health, therefore it was of vital importance for fast and sensitive sensing of nitrofuran antibiotics (NFs). In this study, carbon dots materials with bright blue fluorescence were developed by applying an easy hydrothermal method from rapeseed meal assisted by sulfanilic acid. The sulfanilic acid could not only supply N and S elements, but also effectively break the internal robust chemical structure of rapeseed meal. The skillful doping of N and S contributed to a high QY of 32.4 % for 2SRM-CDs. The luminescent sites of 2SRM-CDs changed with pH, and therefore exhibited an interesting visual response to pH variation. Besides, the 2SRM-CDs showed satisfactory sensitivities and selectivities for furazolidone, nitrofurantoin and nitrofurazone with the limits of detection of 0.354 μM, 0.258 μM and 0.327 μM, when their concentrations were 1.0–330 μM, 0.5–260 μM and 0.5–230 μM,respectively. Furthermore, the as-developed sensor could be successfully used to detect NFs in actual samples, which demonstrated potential in fields such as environmental monitoring and food analysis.