Selecting the right particle size:
The role of resin efficiency (particle size) and selectivity (ligand and pore size) become more important for intermediate purification . The question for the process chromatographer is "What per cent of dynamic binding capacity can I load the resin to and still have adequate resolution from most impurities?"
Many commercial Toyopearl and TSKgel PW bulk resins are offered in particle sizes from 100 µm to 20 µm and have the same methacrylic polymer backbone. The selectivity for feedstock components remains the same regardless of bead size. Intermediate purification steps typically use smaller particles than capture steps.
Toyopearl resins with bead diameters of 35 µm and larger are made to withstand operating pressures up to 3 bar
TSKgel PW resins with bead diameters of 30 µm and smaller are made to withstand operating pressures up to 20 bar.
The viscosity of a customer's intermediate feedstock and the operational pressure limits of the chromatographic hardware used, determine the most appropriate particle size for this process step.
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Tosoh Bioscience has commercial products with the following particle sizes for intermediate purification:
| Grade |
Particle size range
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| M (Medium) |
40-90 µm
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| S (Superfine) |
20-50 µm
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| (30) |
20-40 µm
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Approximate dynamic binding capacities for typical intermediate steps:
(please click on the mode of interest for more product information)
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