Lateral Flow Immunoassay Based Colloidal Gold Nanoparticles for the Detection of Organophosphorous Pesticide (Propanoic) in Cow’s Milk

Simple, inexpensive, and high sensitive Lateral Flow Immunoassay (LFI) based colloidal gold nanoparticles antigen-coated as the label was designed for the fast determination of organophosphorus pesticide in cow’s milk samples. The developed LFI detection strip consisted of four structural zones start from the sample pad, conjugate pad, detection zone, and finally absorbent pad. Immune-sensitive zone was synthesized and functionalized with Propanoic Hapten–OVA, Goat monoclonal-anti-Propanoic antibodies were produced. Propionic -cationized ovalbumin-HPR conjugates were fabricated and identified. The antibody optimal conditions were set and the influence of pH on the analytical properties of the antibody-based gold nanoparticles was also investigated. The detection limit of the LFI for Propanoic standard into milk samples were 0.5 and 100 ng/mL, respectively. The test development time for the LFI was less than 5 min, suitable for fast on-site measuring of Propanoic.