Development of a monoclonal antibody-based lateral flow immunoassay for the detection of benzoic acid in liquid food

To monitor benzoic acid ( BA ) residues in liquid food samples, a monoclonal antibody (mAb)-based lateral flow immunoassay (LFA) was developed in this study. First, 2-aminobenzoic acid ( 2-AA ), 3-aminobenzoic acid ( 3-AA ), and 4-aminobenzoic acid ( 4-AA ) were conjugated to BSA and used as immunogens. After cell fusion, mAb 6D8 from 4-AA-BSA performed best with an IC 50 value of 0.21 mg L −1 using 3-AA-OVA as a heterogeneous antigen, which represented a 3.4-fold improvement compared with the homogeneous antigen 4-AA-BSA . Subsequently, eight kinds of CGNPs with sizes varying from 20.94 nm to 90.00 nm were synthesized for screening the suitable size to develop a sensitive LFA. Finally, a sensitive LFA based on colloidal gold (23.27 nm) nanoparticles was developed for screening BA with a cut-off value of 4 mg L −1 , which could meet the requirement of BA detection in milk, Fanta, Sprite, Coca-Cola, and Smart samples. To monitor benzoic acid ( BA ) residues in liquid food samples, a monoclonal antibody (mAb)-based lateral flow immunoassay (LFA) was developed in this study.