Latex microsphere immunochromatography for quantitative detection of dexamethasone in milk and pork.

Dexamethasone (DEX) is a synthetic long-acting glucocorticoid, which can increase the risk of hypertension and diabetes if it is abused or used improperly. In this study, lateral flow immunoassays (LFIA) based on black and blue latex microspheres (LMs), integrated with a strip reader, was developed for quantitative detection of DEX in milk and pork. The results could be achieved within 15 min. The visible limits of detection (vLODs) were 0.3 ng/mL and 0.7 μg/kg for milk and pork, respectively. The quantitative limits of detection (qLODs) were 0.047 ng/mL and 0.087 μg/kg, respectively. The recoveries ranged from 80.0% to 122.8%. 20 milk and 10 pork samples were analyzed to confirm the performance of the on-site application. The detection results were consistent with the data from LC-MS/MS, indicating the practical reliability of our established assay. The developed LMs-LFIA provides a promising technical support for rapid, sensitive, and on-site detection of DEX.