Columns for cyclic extraction-chromatographic device

Three constructions of the columns of extraction-chromatographic device operating in cyclic mode have been compared. Experiments have been conducted with = shots containing caffeine, coumarin, and salicylic and acetylsalicylic acids using hexane-isopropyl alcohol-water biphase solvent system at a 1 : 1 : 1 ratio, respectively. All columns have demonstrated fairly high effectiveness. The certain advantage of the column with stirrers is the possibility to control contact time of phases.