A sensitivity enhanced fluorescence method for the detection of ferrocyanide ions in foodstuffs using carbon nanoparticles as sensing agents

•A novel fluorescent nanoprobe was developed for [Fe(CN)6]4− detection with high selectivity and sensitivity.•The sensing mechanism was based on the fluorescence quenching of N,S,Cl-CNPs by [Fe(CN)6]4− via dynamic interaction.•The fluorescence method was successfully applied for [Fe(CN)6]4− detection in food stuffs with high accuracy. A novel fluorescent nanoprobe was for the first time developed for the efficient detection of ferrocyanide ions ([Fe(CN)6]4−) based on nitrogen (N), sulfur (S) and chlorine (Cl) co-doped carbon nanoparticles (N,S,Cl-CNPs). The N,S,Cl-CNPs were fabricated through a simple and ultrafast acid-base neutralization method. The sensing mechanism was based on the quenching effect of [Fe(CN)6]4− on the fluorescence emission of N,S,Cl-CNPs via dynamic interaction. The N,S,Cl-CNPs were found to show high selectivity and sensitivity towards [Fe(CN)6]4− detection with two good linear relationships were achieved in the concentration ranges of 0.01–1.0 μg/mL and 1.0–50.0 μg/mL, respectively, and the detection limits are as low as 3.3 and 21.8 ng/mL, respectively. The proposed fluorescence method was successfully applied for [Fe(CN)6]4− analyses in food samples with high accuracy. The results of this study indicate the great application prospects of N,S,Cl-CNPs for [Fe(CN)6]4− detection in complex food matrix.