Development of a Sensitive Monoclonal Antibody-Based Lateral Flow Immunoassay for the Detection of Benzoic Acid in Liquid Food

Abstract

Abstract 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 IC50 value of 0.21 mg/L using 3-AA-OVA as 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 (23.27nm) nanoparticles was developed for screening BA with a cut-off value of 4 mg/L, which could meet the requirement of BA detection in milk, Fanta, Sprite, Coca-Cola, and Stmart samples.