Effects of basic modifiers on sfe efficiencies of ephedrine derivatives from plant matrix

The effect of basified modifiers in supercritical CO₂ (SCF-CO₂) such as diethylamine has been investigated on the SFE efficiencies of ephedrine derivatives (e.g. methylephedrine, norephedrine, ephedrine, and pseudoephedrine) from aerial parts ofEphedra sinica. The addition of basified modifiers in SCF-CO₂ showed a greater enhancement of SFE efficiency of ephedrine derivatives than pure modifiers. These results might be due to the fact that the salts ofEphedra alkaloids (insoluble in CO₂) in plant tissues would be changed to their free bases (freely soluble in CO₂) by basified modifiers such as diethylamine in methanol. In addition to enhancing the solubilities, it could increase the degree of desorption of the compounds from plant matrix. Also, the SCF-CO₂ modified with methanol basified with diethylamine showed a difference of extractability of ephedrine and its diastereomer, pseudoephedrine. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.