• IEX Handbook

    Practical tips and in-depth information in the popular Ion Exchange Chromatography Handbook

  • Principles of IEX - animation

    In less than 2 minutes, see how ion exchange chromatography works.

  • How to select an IEX column

    This selection guide helps you select the most suitable IEX column for your specific sample.

  • IEX products

    Resins and prepacked columns from MonoBeads, Sepharose and Capto resin families

    IEX products

Discover new Capto HiRes chromatography columns

When the highest resolution matters in ion exchange chromatography

Learn more

Ion exchange chromatography: overview

Ion exchange chromatography (IEX) separates proteins with differences in surface charge to give high-resolution separation with high sample loading capacity. The separation is based on the reversible interaction between a charged protein and an oppositely charged chromatography resin. Ion exchange chromatography resins can be used at high flow rates, because binding kinetics for IEX are fast, and rigid chromatography particles can be used.

For in-depth information about IEX, download our IEX handbook.

How does ion exchange chromatography work?

The net surface charge of proteins varies according to the surrounding pH. The pH at which a protein has no net charge is called isoelectric point (pI). Above its isoelectric point (pI), a protein will bind to a positively charged anion exchanger. Below its pI, a protein will bind to a negatively charged cation exchanger.

Proteins bind as they are loaded onto a column at low ionic strength. The conditions are then altered so that bound substances are desorbed differentially. Elution is usually performed by increasing salt concentration or changing pH in a gradient.

IEX is performed in four main steps as shown below. Watch our IEX animation to easily visualize how IEX works.

Equilibration Sample application and wash Elution Regeneration
Prepare the column to the desired start conditions. Bind the target molecules and wash out all unbound material. Biomolecules are gradually released from the ionic exchanger by a change in the buffer composition. Removal of all molecules still bound.

When should I use ion exchange chromatography?

Ion exchange chromatography can be used in any part of a multistep purification procedure.
Download this guide that will show you when and why an IEX step is recommended for a powerful purification protocol.

  • IEX Infographic

    Top 4 tips for high-resolution separation (to give high protein purity) in your ion exchange chromatography (IEX) runs.

  • Tips for high resolution IEX to obtain a pure protein

    Here’s a handy check list of IEX tips and tricks for obtaining well-separated peaks on your chromatogram.

    Read More
  • Reduce hands-on time in your IEX runs

    Explore four tips for reducing IEX hands-on time with automation tools.

    Read more
  • Troubleshooting protein loss during IEX

    Explore five tips for maximizing your protein binding and recovery during IEX.

    Read more
  • Q&As on ion exchange chromatography

    During a webinar on IEX, attendees asked more than 50 questions. We have compiled them into an interactive document.

    Read more
  • How coupling MALS to IEX can help protein characterization

    Mario Lebendiker and Hadar Amartely from The Hebrew University of Jerusalem show how IEX-MALS allows a precise analysis of samples that cannot be resolved by SEC-MALS.

    Read more
  • Working with viscous samples?

    Utilizing a robust, modern, and rigid resin reduces sample run time significantly by allowing high flow rate with low column backpressure

    Read More
  • Structural studies—why “good enough” protein purity might not be enough

    In protein research, what you do next with your pure protein—for example, determining the structure of a protein by X-ray crystallography—determines the level of protein purity that you will need.

    Read more