Automated flow system for sildenafil enrichment using surfactant coated solid-phase with fluorescence detection

► On-line pre-concentration of sildenafil was achieved using XAD-1180 resin with HTAB. ► HTAB-sildenafil micelles were then detected by a spectrofluorometer. ► Sildenafil fluorescence emission was greatly enhanced by micelles of HTAB. ► The great signal enhancement of sildenafil (33-fold) leads to a detection limit of 0.2 ng mL−1. ► This automatized method has a high sample rate of 30 per hour.