Dexamethasone (DE) is a synthetic glucocorticoid that is frequently added to cosmetic products for its good short-term effects, especially in facial masks, but long-term use is hazardous to the health. The abuse of DE in whitening and acne cosmetic products is currently a serious problem in China. It is necessary to establish a rapid method of detecting illegal DE addition in cosmetics. In the present study, a monoclonal antibody (mAb) against DE, 2D5-3D12, was developed that displayed cross-reactivities of 124.5%, 38.8%, 6.7%, 0.9%, 1.1%, 1.82%, and 2.39% with prednisolone, betamethasone, prednisone, beclomethasone, hydrocortisone, triamcinolone, and flumetasone, respectively. A colloidal gold-based lateral flow immunographic assay based on mAb 2D5-3D12 was established and used to determine the DE contents of commercial facial masks. The indicator range of the immunographic assay for DE was 100-200 ng/mL, and the results were consistent with those afforded by LC-MS. This novel method provides the advantages of simple sample treatment, a user-friendly procedure, and rapid detection. Graphical abstract.
