Effects of injection volume on chromatographic features and resolution in the process of counter-current chromatography

Counter-current chromatography is a high efficiency separation and purification technique. As a preparative separation technique, the final goal that we are concerned about is acquisition of maximum yields of the separated compounds under specific conditions. In this paper, the theory of counter current extraction table (TCCET), a numerical model for counter-current chromatography, was employed firstly to investigate the effects of injection volume on chromatographic features (retention time, peak height and peak width) and resolution between the separated compounds from theoretical point of view. Moreover, a series of experiments were performed to evaluate the effectiveness of the TCCET model when used for analysis of the influences of the injection volume on a counter-current chromatography separation process. Both the theoretical analysis and experiments show that: (1) the retention time or retention volume increases with the injection volume linearly; (2) the peak height increases with increase of the injection volume, and when the injection volume is smaller than ten percent of Vm (volume occupied by mobile phase in a CCC column), the relationship between the peak height and the injection volume is a kind of linear relationship; and (3) the peak width also increases with increase of the injection volume, and obvious linear relationship between the peak width and the injection volume can be observed when the injection volume is smaller than a certain volume. In contrast, the resolution between the separated compounds decreases with increase of the injection volume.