Enrichment of tocopherol by coupled supercritical fluid extraction/preparative supercritical fluid chromatography is described. Wheat germ powder is used as the starting material and is subjected to supercritical fluid extraction with carbon dioxide. The extracted oil containing tocopherols is concentrated and trapped on a silica gel column by reducing the pressure of carbon dioxide. The trapped oil is then eluted and separated on a silica gel column of 20 mm i.d. x 20 mm length. The column effluent is fractionated by monitoring UV absorption at 290 nm. With this method, tocopherol content of the wheat germ is enriched 100-fold.

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Abstract. Mixing, hence dilution, of organic sample solvents with a carbon dioxide mobile phase was an effective method for solute focusing. Mixing was affected by the density differences between sample solvents and mobile phase as well as the orientation of the injector assembly. The use of two mixing chambers connected in series improved mixing and allowed a 1-pL injection.

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