GC/MS (Gas Chromatography/Mass Spectrometry)

The method is based on utilizing solid phase extraction columns, specifically designed with cation exchange capability. After buffering to the neutral pH range, the specimens are extracted on an ion exchange column. Using a basic solvent mixture, the drug of interest is then eluted. This extraction solvent is evaporated at low temperatures to dryness. The extract is reconstituted in solvent, and then injected into the HP 5890 GC / HP 5970 MSD. Identification and / or quantitation of the drug is performed by monitoring the retention time for the desired peak, and by monitoring a group of selected drug / ISTD ions for each peak(s) as indicated by the mass spectrometer.