Many friends who are new to the field of chromatography are relatively unfamiliar with the term preparative chromatography. In fact, chromatography and thin-layer chromatography, which are widely used in chemistry, chemical industry and medicine, are more typical preparative chromatography. In other words, the injection volume of analytical chromatography is increased, and a large amount of required substances (fractions) are obtained at the same time. The process can be called preparative chromatography. The purpose of analytical chromatography is to analyze the content of one (or several) pure substances in a mixture. The purpose of preparative chromatography is to obtain pure substances from the mixture. The preparative chromatography system is a general term for the combination of multiple analysis and testing equipment that use the idea of ​​preparative chromatography to obtain purified substances with high efficiency.
 
    Analytical chromatography is the basis of preparative chromatography. When we have achieved a good separation effect on analytical chromatography, we can enlarge it and apply it to preparative chromatography. Therefore, we need to consider adjusting the sample amount, flow rate, and gradient:
 
    1. Adjustment of sample amount:
 
    It is related to the column length and inner diameter of the analytical column and the preparative column:
 
    For specific relationships; sample volume on the preparative column / sample volume on the analytical column = preparative column length / analytical column length * the square of the internal diameter of the preparative column / the square of the internal diameter of the analytical column;
 
    2. Adjustment of flow rate:
 
    Preparative column flow rate/analysis column flow rate=preparation column volume/analysis column volume=preparation column length/analysis column length*preparation column inner diameter square/analysis column inner diameter square;
 
    3. Adjustment of gradient:
 
    Preparative column gradient/analysis column gradient=preparation column volume/analysis column volume*preparation column flow rate/analysis column flow rate;