Golden rules and pitfalls in selecting optimum conditions for high-speed counter-current chromatography

Preparative isolation and purification of alkannin/shikonin derivatives from natural products by high‐speed counter‐current chromatography

“…Therefore, an effort was made to optimize the above proposed solvent system, aiming to one where both K values will be sufficient but also hydrodynamic equilibration can be achieved quickly, based on previous articles on HSCCC (Ito, 2005). After alternating the volumes of the solvents comprising the above solvent system, the optimum stable system selected was n-hexane:ethyl acetate:ethanol:water 24:22:14:21 v/v/v/v (system 1; settling time 20 s).…”

“…According to HSCCC rules proposed by Ito (2005), the two-phase solvent system applied therein could be improved for better separation. Additionally, in that paper purity assay was performed by HPLC-DAD that according to our recent paper , detects mainly monomeric A/S derivatives and not dimeric and oligomeric ones that co-exist in most of the natural and commercial samples containing monomeric A/S derivatives.…”

Preparative separation of quaternary ammonium alkaloids from Coptis chinensis Franch by pH-zone-refining counter-current chromatography

“…It extends the capability of standard high-speed countercurrent chromatography (HSCCC) by various ways including an over ten-fold increase in sample loading capacity, high concentration of fractions, high purity, concentration of minor impurities, etc. In addition, this method enables detection of samples by their pH, which is especially useful if the analyte has low ultraviolet absorbance [2,3,5]. It has been successfully used as a large-scale preparative technique for separating ionizable compounds which include alkaloids [6][7][8], synthetic colors [9,10], isomers [11][12][13], peptide derivatives [14,15], etc.…”

“…pH-Zone-refining counter-current chromatography (pH-zone-refining CCC) is a kind of liquid-liquid partition chromatography that enables the separation of organic acids and bases into a succession of highly concentrated rectangular peaks that elute according to their pK a values and hydrophobicities [1][2][3][4]. It extends the capability of standard high-speed countercurrent chromatography (HSCCC) by various ways including an over ten-fold increase in sample loading capacity, high concentration of fractions, high purity, concentration of minor impurities, etc.…”

Extraction and isolation of dictamnine, obacunone and fraxinellone from Dictamnus dasycarpus Turcz. by supercritical fluid extraction and high-speed counter-current chromatography

“…Large K D -value usually tends to produce excessive sample band broadening, while small K D -value results in a poor peak resolution. 22,23 In this experiment, the solvent system based on nhexane-ethyl acetate-methanol-water at different volume ratios were tested ( Table 1). As shown in Table 1, the K D -value of the compound 2 in the solvent system of n-hexane-ethyl acetate-methanol-water (1:0.5:1:0.5) was too small, while it was difficult to separate compound 1 and 3 for the close K D -value.…”