High speed countercurrent chromatography (HSCCC), developed by Dr. Ito from the National Institutes of Health in the United States in 1982, is a novel and continuous liquid-liquid distribution chromatography technique. Unlike other chromatography techniques, HSCCC does not require any solid carrier, thus avoiding adverse effects such as contamination, deactivation, denaturation, and irreversible adsorption caused by reactions between the surface of the solid carrier and the sample. At the same time, it also has the advantages of wide applicability, speed, large injection volume, low cost, and high recovery rate. Therefore, it has been widely applied in the fields of biology, medicine, food, materials, cosmetics, and environmental protection, especially in the field of separation and purification of active ingredients in natural products, which is highly valued.

High speed counter current chromatography is a counter current chromatographic separation method based on a unidirectional fluid dynamic equilibrium system. It was accidentally discovered while studying the fluid dynamic equilibrium of a rotating tube. When the spiral tube rotates slowly, both phases in the spiral tube are distributed from one end to the other. When using a certain phase as the mobile phase to elute from one end to the other, the retention value of the other phase in the spiral tube is about 50%, but this retention amount decreases with the increase of the mobile phase flow rate, resulting in a decrease in separation efficiency. But when the speed of the spiral tube is increased, the distribution of the two phases changes. When the speed reaches the critical range, the two phases will separate along the length * of the spiral tube, with one phase occupying a section of the leading end, which we call the leading end, and the other phase occupying a section of the trailing end, which is called the trailing end phase. High speed counter current chromatography utilizes the unidirectional distribution characteristics of two phases. At high rotation speeds of the helical tube, if it is fed from the tail end to the head end, it will pass through the tail end phase and move towards the head end. Similarly, if it is fed from the head end phase to the tail end, it will pass through the head end and move towards the tail end of the helical tube. When separating, one phase (fixed phase) is first injected into the spiral tube, and then the mobile phase is pumped in from the appropriate end, allowing it to distribute the sample infinitely in the spiral tube. The faster the instrument speed, the more fixed phase is retained, the better the separation effect, and greatly improves the separation speed, hence it is called high-speed countercurrent chromatography.

Briefly describe the product advantages of high-speed countercurrent chromatography:

1. Due to the infinite composition and ratio of solvent systems, they can theoretically be applied to the separation of samples within any polarity range, and have their unique advantages in separating natural compounds. Due to the fact that the fixed phase in polytetrafluoroethylene tubes is liquid and does not require a solid carrier, it can eliminate the adsorption loss caused by the use of solid carriers in solid-liquid chromatography, making it particularly suitable for separating polar substances.

2. Easy to operate and master: High speed countercurrent chromatography is easy to operate, with low requirements for sample pretreatment, and can be used for the preparation, separation, or analysis of general crude extracts.

3. High recovery rate: No solid phase carrier is required, eliminating losses caused by irreversible adsorption and degradation of the sample on the solid phase carrier. Theoretically, the recovery rate of the sample can reach. In experiments, as long as the separation conditions are adjusted properly, there is generally a high recovery rate.

4. Good reproducibility: If the sample does not have strong surface activity and acidity, even with multiple injections, the separation process remains stable and the reproducibility is quite good.