Abstract:Carmine (CRM) is one of the most widely used azo pigments in the Chinese food industry. Its carcinogenic and mutagenic effects have attracted increasing attention. The establishment of a fast, sensitive, and accurate CRM detection method is of considerable importance to protect human health. In this study, a fluorescence detection method based on nitrogen, sulfur, phosphorus, and chlorine co-doped carbon dots (N,S,P,Cl-CDs) was established for the rapid detection of CRM in food. With glucose as the carbon source, and ethylenediamine, phosphoric acid, hydrochloric acid, and sulfuric acid as heteroatom donors, blue emissive N,S,P,Cl-CDs were prepared by exothermic acid-base neutralization. The fluorescence of N,S,P,Cl-CDs was effectively quenched by CRM through static interactions and inner filter effects. N,S,P,Cl-CDs showed high selectivity and sensitivity for CRM detection. In the concentration range of 0.01~14.0 μmol/L, CRM demonstrated a good linear relationship with the fluorescence quenching efficiency F0/F, and the detection limit was as low as 9.38 nmol/L. The developed method was tested for CRM detection in food matrices. The recovery rate was between 97.8% and 101.5%, and the relative standard deviations were less than 3.29%, showing the high accuracy of the proposed method. These results demonstrate that the established fluorescence detection method can be applied for rapid CRM detection in real food.
