Capto™ ImpRes ion exchange chromatography resins are designed for high-throughput intermediate purification and polishing steps of a wide range of biomolecules in bioprocess applications. These resins are based on high-flow agarose and offer excellent resolution in bioprocessing.

You can pack Capto™ ImpRes in large-scale columns to allow high flow velocities and high bed heights and increase the productivity and flexibility in your process design. To achieve effective purification, you need to be sure that the resin is efficiently packed. Poorly packed columns can lead to costly disruptions and loss of your valuable product. Robust and verified packing and testing methods can eliminate such concerns and risks.

This article explains best practices to help you efficiently pack Capto™ SP ImpRes, Capto™ Q ImpRes, Capto™ MMC ImpRes, and Capto™ adhere ImpRes chromatography resins in our large-scale AxiChrom™, BPG, and Chromaflow™ chromatography columns. Best practices for packing MabSelect PrismA™ can be found in this article.

Result examples in the three packed columns, respectively are seen in the accordions at the bottom of this document.

Capto™ ImpRes chromatography resin characteristics

Our Capto™ ImpRes resins are based on highly rigid agarose that allows high flow velocities, which is essential for raising productivity in large-scale operations. The small average bead size of 40 µm gives you high resolution in your bioprocessing.

Capto™ ImpRes resins offer you a wide range of bed heights and flow velocities. The pressure-flow specification for Capto™ ImpRes in large columns is 220 cm/h at less than 3 bar (0.3 MPa, 43.5 psi) and at a 20 cm bed height (tested with water at 20°C in a 1 m diameter column).

General packing considerations


The height of a gravity-settled bed differs from the height of a bed settled under low flow (consolidated) due to the properties and the behavior of the resin under different conditions. Therefore, you should separate the compression factor (CF) from the packing factor (PF). For example, in water, when consolidated at 30 to 60 cm/h, the PF is 1.15 and the CF is 1.12 for Capto™ ImpRes.

Equations to calculate CF, PF, and column volume (CV) are shown below:

Compression factor, CF = Lsettled / Lpacked

Packing factor, PF = Lcons / Lpacked


Lsettled = bed height measured after settling by gravity

Lcons = consolidated bed height, that is, bed height measured after settling the resin at a given flow velocity

Lpacked = packed bed height

CV = Lpacked × AC


AC = cross-sectional area of the column

When packing BPG and AxiChrom™ columns, PF is used in the packing procedure to calculate the final packed bed height after the consolidation step. CF is used in the chromatography resin preparation step to calculate the resin volume needed to pack a desired bed height. Because Chromaflow™ columns are pack-in-place columns, they have no registered consolidated bed heights, and the CF is used throughout the packing process.

Properties of Capto™ ImpRes resins in various packing solutions

Capto™ ImpRes resins settle quickly in water, in 20% ethanol, and in salt solutions for packing. When you use these solutions, remember to rinse tubing and nozzles directly after packing to prevent clogging of the flow path.

Adding salt to packing solutions slows the settling of the resin beads and allows them to settle less tightly. Therefore, it is very difficult to measure slurry concentration by gravity with salt-based solutions. However, the slurry concentration method described below allows for quick and accurate determination of slurry concentration.

When Capto™ ImpRes resins are settled at 30 to 60 cm/h, the consolidated bed height will be 3% to 7% higher in salt solution compared to in water or 20% ethanol. The effect is almost the same for 10 mM NaCl as for 0.4 M NaCl and can be compensated for by using different PF. Table 1 shows PF for water and a variety of other packing solutions. However, for optimal performance of the packed bed, we recommend specific packing solutions for different column types and sizes, which is further described in this article or available through UNICORN™ Intelligent Packing wizard.

Table 1. PF required for a 20 cm bed of Capto™ ImpRes in different solutions for optimal bed performance where the bed is consolidated at 30 to 60 cm/h

Solution Capto™ Q ImpRes and Capto™ adhere ImpRes Capto™ SP ImpRes and Capto™ MMC ImpRes
Water 1.15 1.15
20% ethanol 1.15 1.15
10 mM NaCl 1.20 1.20
400 mM NaCl 1.20 1.20
20% ethanol with 200 mM sodium acetate N/A 1.20

Slurry preparation

To achieve the correct amount of chromatography resin for packing to target bed height or compression, it is important that you measure slurry concentration correctly. When you prepare the slurry, start by calculating the chromatography resin volume (V) needed to pack the desired bed height. You can determine the slurry concentration in several ways, but to get an accurate slurry concentration of Capto™ ImpRes resins in salt-containing solutions, we recommend the Slurry Concentration Kit, which contains all the materials required for determination of slurry concentration.

Preparing the resin to form a slurry can be performed manually by shaking/stirring or using a mixer such as Media Wand™ slurry mixing and transfer tool. Shaking gives good results but is often not practical for larger volumes. When stirring, it is preferable to use soft stirrers without sharp edges. Media Wand™ suspends the resin directly in the container and transfers the slurry to BioProcess™ Resin Mixer in one operation, which makes it suitable for large-scale packing.

Capto™ SP ImpRes and Capto™ MMC ImpRes is supplied in 20% ethanol with 0.2 M sodium acetate. Capto™ Q ImpRes and Capto™ adhere ImpRes is supplied in 20% ethanol. Before packing, transfer the resin to the packing solution as described in the instructions for the column that you intend to pack.




We describe packing of Capto™ ImpRes resins in AxiChrom™ columns using the custom mode feature of Intelligent Packing, as well as packing of Capto™ ImpRes resins in BPG and Chromaflow™ columns.

Capto™ ImpRes can generally be packed in AxiChrom™, BPG, and Chromaflow™ columns to bed heights between 10 and 40 cm. See specific column type for details. The flexibility of column diameters and bed heights gives you full utilization of Capto™ ImpRes resin flow capacity, allowing for processes with increased bed heights if your floor space is limited or at lower bed heights and larger diameters to decrease process time. We describe each packing method in relation to a specific packing solution. Deviation from use of the packing solutions described may have significant impact on the PF and subsequently on the packing result.

To utilize the full flow potential of the Capto™ ImpRes resin, we recommend using AxiChrom™ in your process.