Development and evaluation of a spiral tube column for counter-current chromatography

An improved type-J counter-current chromatography (CCC) planet centrifuge with two spiral tube columns (volume 2×15 mL, β value 0.3-0.7, tubing 0.8 mm id) was developed and evaluated for its retention ability of four typical different solvent systems including heptane-methanol (1:1, v/v) (A), hexane-ethyl acetate-methanol-water (1:1:1:1, v/v) (B), n-butanol-acetic acid-water (4:1:5, v/v) (C), PEG1000-K(2)HPO(4)-water (12.5:12.5:75, w/w) (D) under eight different operation modes. The results indicated that the spiral tube column could significantly increase the retention of four typical solvent systems compared with a traditional multilayer coil column with similar parameters (volume 35 mL, β value 0.3-0.7, tubing 0.8 mm id). The retention of stationary phase (S(f)) for the less polar system (A) and moderately polar solvent system (B) can be increased by about 10%, and for the polar system (C) and aqueous two-phase system (ATPS) (D) by 30-40%. The preliminary applications of this spiral tube column to the separation of small molecular compounds such as moderately polar theaflavins, polar anthocyanins and dipeptides were successful. Acceptable resolution can be obtained between cytochrome c and myoglobin, lysozyme and myoglobin when it was applied on protein separation; however, it still needs to be improved with regard to its column efficiency.