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Chromatography / Preparative HPLC

Preparative LC

External flow cellTask for preparative HPLC systems differs to analytical one. While analytical HPLC task is qualitative and quantitative determination of defined compounds in samples, preparative HPLC task is separation, purification and isolation of value products from mixtures.

Preparative chromatography can be devidet into three main areas:

  • Semi-preparative separations
  • Batch preparative chromatography (pilot or industrial scale)
  • True Counter-current chromatography
  • Simulated moving bed (SMB)
  • Continuous chromatography

Scale definition

Parameter Analytical Semi-preparative Preparative
Column sizes (mm) 120 - 250 x 2 - 4.6 120 - 250 x 8 - 16 120 - 250 x 20 - 62
Particle size (µm) up to 5 5 - 10 higher than 10
Stationary phase (g) up to 5 5 - 30 50 - 450
Tubings 1/16" 1/16" 1/8"
Flow rates (ml/min) 0.1 - 2 5 - 50 100 - 1000
Sample size (mg) 0.01 - 2 0.1 - 50 1 - 700
Flow cell (mm) 10 3 0.5 - 2

SMB

The simulated counter-current process (Simulated Moving Bed - SMB) was developed in the early 60th by the Universal Oil Products Company. It was mainly applied to industrial-scale separations, like the xylene separation or the fructose-glucose separation.

There is a strong analogy between the SMB and the TMB process. Under the use of a suitable system of adsorbent and eluent, a feed stream is separated into two withdrawal streams containing the pure components of a binary or pseudo-binary mixture.In the SMB process a large column is divided into a finite number of small sections. A withdrawal tube is situated between two of such sections.These tubes are connected in a cyclic mode with the inlets and outlets via a special designed rotary valve (Knauer). An observer sitting on an in- or outlet remarks anapparent moving of solid counter-current the fluid flow at each switching although the solid is fixed in the column. Therefore, the process is called a simulated counter-current one. The SMB is equal to TMB for an infinite numberof columns.

General principle of SMB process

SMB process


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