Extraction of major alkaloids from poppy straw with near-critical mixtures of carbon dioxide and polar modifiers.

Near-critical extraction of major alkaloids from poppy straw was performed successfully with a simple device consisting mainly of two chromatographic pumps and a pressure regulator. The optimum extractant, consisting of carbon dioxide, methanol and water, gave a quantitative extraction of thebaine, codeine and morphine in 20 min. The method was compared with a classical liquid-solid extraction procedure and carbon dioxide was shown to act as a transporting agent of the extraction solvent (methanol-water) into the vegetable matrix.

Separation of opium alkaloids by carbon dioxide sub- and supercritical fluid chromatography with packed columns. Application to the quantitative analysis of poppy straw extracts.

The optimization of the separation of seven opium alkaloids by sub- and supercritical fluid chromatography (SFC) using packed columns and carbon dioxide as the primary mobile phase was studied. The influence of aminated polar modifiers on bare and aminopropyl-bonded silica was investigated. It was found that the presence of an amine in the mobile phase could enhance the retention of alkaloids on aminopropylsilica. Various separation schemes were possible depending on the type of analysis needed. An aminopropyl-bonded silica used with a carbon dioxide-methanol-triethylamine-water mixture (82.95:16.25:0.50:0.30, w/w) gave a very rapid separation (2 min). A bare silica with a carbon dioxide-methanol-methylamine-water mixture (83.37:16.25:0.15:0.23, w/w) gave longer analysis (10 min) but a higher resolution. This last procedure was applied to a poppy straw extract and to the determination of three alkaloids of interest after a peak purity study using a diode-array UV detector. For these alkaloids, SFC appears to be a promising technique for the routine analysis of opium alkaloids.