Knowledge about large prep and process scale columns
Preparative and Industrial scale Solid Phase Extraction, Batch Adsorption, LC, Flash, MPLC, HPLC and SMB is about purification and isolation of milligram to kilogram amounts of compounds. Every mode produces different yield and purity of compounds and has different cost structures.
As we move from LC to HPLC operating pressure is increased. As we increase pressure we also increase choice of solvents to be used, plant complexity and equipment costs. We also decrease range of molecules that can be separated, extracted or purified. Under higher pressure some molecules break apart, protein type of molecules denature.
Criteria for using large scale columns
The criteria governing preparative and industrial scale separations are market driven. Economic considerations are most important. They are governed by the following factors.
Separation Strategy: By optimising the separation between the peak of interest and the nearest contaminant, high sample loads can be achieved without compromising product purity.
Loadability is controlled by the silica particles’ pore size and available surface area. The smaller the pore size the larger the surface area. . Application of the smaller pore size silicas is limited by the range of molecular weight materials they can chromatograph.
The lifetime of a column is often dependent on the silica’s chemical stability. Conditions of use will be very important.
The robustness of a silica will determine how many times a material can be repacked into a column. Reversed-phase is the dominant technique used in analytical HPLC. Normal-phase HPLC is still often used in preparative separations due to the high cost of reversed-phase materials and the easier recovery of solute from the organic solvents used.
Two strategies dominate the approach to preparative HPLC. In the ‘scale-up’ approach a method developed for analytical purposes is directly applied to a larger i.d. column. Although typical 3 - 5Ám particles may be replaced with 10 Ám material of identical selectivity, high preparative efficiencies are maintained. Such an approach is particularly suitable for purifying gram quantities of material with low k'-values.
In the alternative ‘overload’ approach resolution is sacrificed by operating the column in an overload situation. Such high loadings maximise column capacity. Separations are poorer but gram to kilogram amounts of material may be purified.
A comparison of scale-up parameters is highlighted in Table 1.
Table 1. Column Capacity
1 Assumes 250 x 4.6 mm column contains 2.5g material : 2 Scale-up approach, 3 Overload approach
The technique uses larger particle size silicas, polymers and wider internal diameter columns than in analytical HPLC. Column efficiency can be preserved on scale-up from analytical to preparative separations. However, broader lower efficiency chromatographic peaks are more often observed when the column is used in an overload state.
Critical Components in a HPLC Column
Bulk Preparative Materials
We distributes most commercially available preparative HPLC bulk materials. For details please contact us
New Style Prep HPLC Columns
SieLC Prep Column with inbuilt pre-column
The SieLC Prep-column outperforms all previous hardware styles and offers significant benefits to both the column manufacturer and the column user.
New hardware offers:
The stationary phase carrying column and Frit is made of SS. The outer body is mande of anodized aluminium. Top and bottom of the column is sealed with PEEK rings.
UPack - Self Packing Prep-Column
SIELC Technologies introduces new preparative chromatography self-packing re-usable column hardware. It is available in 20 mm, 30 mm, and 50 mm ID format. The hardware allows to pack columns in a regular chromatography lab, using only a preparative HPLC pump. The device has a built-in switching valve with position for column packing (fill) and a position for column operation.
No additional equipment is required if you have prep LC system
Simple and inexpensive way of making your own prep columns in 3 steps.
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