Determination of captopril in human plasma with precolumn derivatization using solid phase extraction and HPLC

A rapid, accurate and sensitive method for the determination of captopril in human plasma was developed by solid phase extraction and high performance liquid chromatography (HPLC), using precolumn derivatization of captopril with chromophore label o-phethaldialdehyde (OPA). The extraction of captopril from human plasma was carried out by an amino propyl cartridge. A 0.01 M solution of HCl in methanol showed the best recovery and was chosen for elution of captopril in cartridge. This methanolic solution was applied to react with aqueous solution of OPA and glycine as a coderivatization reagent. The process of derivatization was completed within 2 min at room temperature. The derivatized captopril was injected into a reverse phase HPLC system. Mobile phase was consisted of water:acetonitrile:trifluoroacetic acid (85:15:0.1 v/v/v) with a flow rate of 1 ml min^?1 and detector was used at 345 nm. Linear dynamic range and limit of detection were found as 0.1–6 ppm and 0.1 ppm, respectively.