Indirect determination of captopril by AAS

An indirect method is described for the determination of captopril (KPL) in pharmaceutical preparations by atomic absorption spectrometry (AAS). The procedure is based on the complexation of KPL with an excess of Pd(II) ion. The unreacted Pd(II) was resoluted on a cationic ion-exchanger resin, while Pd(II)-KPL sequestrate was not retained. The effluent Pd(II) sequestrade was measured by AAS. The absorbance is found to increase linearly with increasing KPL concentration, because the amount of Pd(II) is related to the concentration of KPL, which is corroborate by the calculated correlation coefficient value of 0.9939. The system obeys Beer's law for 1-40 microg ml(-1), S.D. was found to be 0.039 (n = 5). The Pd(II)-KPL complex was obtained in the solid phase. Characterization of the complex was performed by elemental analysis, TG, conductance measurements and IR, 1H-NMR spectroscopy.