Detection of Tadalafil and Its Analogues in Health Wine and Oral Liquid by Microwell Lateral Flow Immunochromatography Assay

To monitor illegal addition of tadalafil and its analogues in health food, a new polyclonal antibody was prepared by immunizing New Zealand white rabbits with a common skeleton structure hapten combined with an unsaturated linear alkyl arm hapten strategy, which could simultaneously recognize tadalafil, amino tadalafil and N -Desmethyl tadalafil. A microwell lateral flow immune- chromatographic assay ( mw LFIA) method combined with simple sample pretreatment was developed. The mw LFIA showed that the LOD for three tadalafil drugs was between 0.05 ng mL −1 and 0.30 ng mL −1 , the cut-off values were between 50 ng mL −1 and 100 ng mL −1 . Cross-reactivity (CR) results showed no interference from substances with similar structures, indicating a good specificity against tadalafil, amino tadalafil and N -Desmethyl tadalafil. The average recoveries of three drugs in spiked health wine and oral liquid ranged from 78.7% to 117.8% with an RSD of less than 15%, showing a good aggreement with the results of HPLC-MS/MS method. The developed mw LFIA strip was suitable for the rapid detection of tadalafil and its analogues in health wine and oral liquid samples.