Quantum Dots-based Fluorescence Quenching Immunoaffinity Test Column for the Quick Detection of Rhodamine B in Tomato Sauce

Objective:A novel fluorescence quenching immunoaffinity test column(FQ-ITC)assay,based on the principles of antigen-antibody specific reactions and fluorescence resonance energy transfer(FRET),was developed to determine rhodamine B(RB)residues in tomato sauce. Methods:The FQ-ITC assay was composed of one detection layer made of RB-antibody gel,which was prepared by the conjugation of RB-specific antibody with CNBr activated sepharose-4B. Based on the specific reaction of antigen-antibody and the electrostatic attraction between RB and quantum dots,a novel fluorescence quenching of immune affinity gel column was established,with optimizing the addition amount of antibody,the dilution ratio of quantum dots,incubation time and the addition amount of RB. And then the column was applied in the detection of rhodamine B in tomato paste sample. Results:When 1.0 g hydrobromide activated sepharose 4B was reacted with 2.0 mg monoclonal antibody,the quantum dots was diluted 3000-fold,the incubation time was 50 s,and the addition amount of RB was 3.0 mL,the limit of detection(LOD)of this assay in assay buffer reached the minimum 1.0 μg/L,and the limit of detection of assay for RB in tomato sauce samples was 5.0 μg/L. Besides,the results of the established method were in good agreement with HPLC. Conclusion:The FQ-ITC using QDs allows for simple,sensitive,time-saving,rapid detection of RB in tomato sauce samples on-site.