Stereoisomeric purity determination of captopril by capillary gas chromatography

The GC method developed for the stereoisomeric purity determination of captopril is based on the combined information derived from the analyses of the captopril sample on two GC systems, one with a chiral and the other with an achiral column. The limit of detection has been determined to be 0.02% (w/w) for (R,S) or (S,R) and 0.03% for (R,R), with corresponding minimum quantifiable levels of 0.08% and 0.09%.