Gold Immunochromatography Assay for the Rapid Detection of Spiramycin in Milk and Beef Samples Based on a Monoclonal Antibody

Spiramycin (SP) residues in food do harm to human health. It is necessary to establish rapid detection method for SP. In this work, a monoclonal antibody (mAb)‐based gold immunochromatography assay (GICA) is developed for the rapid detection of SP. Under optimum conditions, the half‐maximal inhibitory concentration of SP‐mAb is 0.43 ng mL–1. The subtype of SP‐mAb is IgG2b. This antibody has no cross‐reactivity with other analogues and has high affinity (4.52 × 1010 L mol–1). Qualitative results can be visualized with the naked eye, with a visual detection limit of 1.0 ng mL–1 and cut‐off value of 10 ng mL–1. A hand‐held strip scanner is used for the quantitative analysis, with LOD 0.43 ng mL–1 in assay buffer. The recoveries of SP ranged from 72.3% to 112% in milk and 98.5% to 115% in beef, with variable coefficient ranging from 9.4% to 11.7% in milk and 8.14% to 15.4% in beef. Besides, the proposed GICA method for SP is confirmed by LC–MS/MS in SP‐spiked milk and beef samples. Overall, the developed GICA can be a useful tool for SP residues on‐site screening in milk and beef samples.