Rabbit Monoclonal Antibody-Based Lateral Flow Immunoassay Platform for Sensitive Quantitation of Four Sulfonamide Residues in Milk and Swine Urine

Abstract

Based on the available rabbit monoclonal antibody (RabMAb), a rapid and sensitive lateral flow immunoassay (LFA) platform has been developed for quantitative detection of four sulfonamide residues(SRs) of sulfadiazine (SD), sulfathiazole (STZ), sulfapyridine (SP), and sulfamethoxazole (SMX).Within the designed LFA competitive format assay, which was based on antigen-antibody properties, the hapten conjugate N¹-[4-(carboxymethyl)-2-thiazolyl] sulfanilamide linked to protein ovalbumin (TS-OVA) and goat anti-rabbit antibody were sprayed as capture and control reagents, respectively, and then the antibody was conjugated to colloidal gold particles as the detection reagent. With quantitative assessment aided by a colorimetric strip reader, the sensitivities of the established LFA method for SD, STZ, SP, and SMX were 0.91 ng mL⁻¹, 0.10ng mL⁻¹,0.12ng mL⁻¹, and 2.13ng mL⁻¹, and the half-maximum inhibition concentrations (IC₅₀) were 5.19 ng mL⁻¹, 1.25 ng mL⁻¹, 0.66 ng mL⁻¹, and 24.14 ng mL⁻¹, respectively. The recoveries at three spiked levels (5, 20, 50 ng mL⁻¹for SD, STZ, and SP; 20, 50, 100 ng mL⁻¹ for SMX) were in the range of 78.02–135.10% and 76.40–137.16% for milk and swine urine, respectively. More importantly, the detection performance of the established platform was consistent with that of in-parallel LC-MS/MS analysis. In conclusion, the proposed LFA platform has showed the potential for fast, sensitive and relatively accurate quantification of four sulfonamide residues in practical uses.

Keywords:

• Lateral flow immunoassay
• Quantitation
• Rabbit monoclonal antibody
• Sulfonamides

Acknowledgments

This research was supported by the National High Technology Research and Development Program of China (863 Program) No. 2007AA10Z436.

Notes

Note: Swine urine were spiked with SD, STZ, and SP at 5, 20, and 50 ng mL⁻¹ while SMX at 20, 50, and 100 ng mL⁻¹, respectively, and each concentration of samples were analyzed in triplicate. RC%, recovery percentage; SD, standard deviation; CV, coefficient of variation.

Milk were spiked with SD, STZ, and SP at 5, 20, and 50 ng mL⁻¹ while SMX at 20, 50, and 100 ng mL⁻¹, respectively, and each concentration of samples was analyzed in triplicate. RC%, recovery percentage; SD, standard deviation; CV, coefficient of variation.