Automated determination of total captopril in urine by liquid chromatography with post-column derivatization coupled to on-line solid phase extraction in a sequential injection manifold

► We developed a fully automated method for total captopril. ► Total captopril was determined in human urine. ► Sequential injection was coupled to liquid chromatography. ► Sample preparation was carried out on-line. ► Captopril was determined after post column derivatization.