Ion chromatography (IC) is an analytical chemistry technique used across environmental, pharmaceutical, industrial, and food and beverage labs to analyze ions and polar molecules that cannot be easily separated using high-performance liquid chromatography (HPLC). It separates and detects ions based on their interactions with a stationary phase (resin) and a mobile phase (eluent).

Much like HPLC, ion chromatography systems include an autosampler, pump, separation column, and detector. In addition, IC systems include a unique component called a suppressor, which helps the peaks from sample components stand out from background noise in the chromatogram.

How does ion chromatography work?

Ion chromatography can be defined as a combination of three concepts: ion-exchange separation, eluent suppression and conductivity detection.

In ion chromatography, the stationary phase is the charged resin inside the column. The mobile phase is a gradient of acidic or basic water-based eluent that helps separate the components of the sample based on charge. The column, called an ion-exchange column, is oppositely charged from the sample ions and the eluent.

When the sample and eluent enter the column, their charged compounds compete for particle binding sites on the column. Ions that have a weaker affinity to the stationary phase will exit the column first, while ions with a stronger affinity to the stationary phase will spend more time interacting with it and exit the column last. For negatively charged samples, this separation process is known as anion-exchange separation. For positively charged samples, it is cation-exchange separation.

Once the components of the sample are separated in the column, the eluent and sample pass through the suppressor before they reach the detector. The suppressor is the key to generating clean data, as it removes background noise caused by the conductivity of the eluent. It uses chemical or electrolytic reactions to reduce the charge of the eluent prior to it reaching the detector, ensuring a chromatogram with the best possible peak resolution.

How does ion chromatography work?

Finally, the eluent and sample reach the detector. Conductivity detection is the primary form of detection used in ion chromatography. However, other forms of detection, like electrochemical or mass spectrometric detection, may be used for increased sensitivity and selectivity of ion analysis.

As a leader in ion chromatography innovation, we have industry-leading, free resources you can use to help teach your students. Our Introduction to Ion Chromatography video quickly and clearly explains IC concepts, while our eTextbook provides the theory and chemistry behind each aspect of the system.

Introduction to Ion Chromatography

Learn the basics of ion chromatography from this quick and educational whiteboard video.

We recommend using EPA Method 300.1 – Determination of Inorganic Anions in Drinking Water by Ion Chromatography – to teach students how to accurately monitor inorganic ions in a variety of water types.

Adequate concentrations of inorganic anions in water are critical to human health and the ecosystem. However, it is also important that the concentrations are not too high. For example, excess fluoride can lead to fluorosis, acne, and neurological issues, while excess phosphate can threaten plant life by reducing sunlight in river water. EPA Method 300.1 will teach your students how to use ion chromatography to accurately monitor inorganic anions in water, including surface, ground, drinking, and wastewaters.

The following application notes provide examples of how EPA Method 300.1 can be performed using a Thermo Scientific Dionex Easion IC System or Thermo Scientific Dionex Aquion IC System. You can find additional application notes in the Resources section.

 Dionex Easion Ic System
Dionex Easion IC System
Dionex Aquion IC System
Dionex Aquion IC System
Why it matters
 3D Product Tour3D Product Tour 
DescriptionSimple system for everyday analyses with everything you need in one compact package.Robust system offering reproducible results for common ion chromatography analyses. Optional features can be added any time to meet changing analytical needsEasy and flexible technology that provides a meaningful introduction to IC
DimensionsH 13” W 9.5” D 15.7”H 22.1” W 8.8” D 21”Small footprint means your lab can easily accommodate other technologies
SoftwareThermo Scientific Chromeleon Chromatography Data System (CDS) Version 7.2.10Thermo Scientific Chromeleon Chromatography Data System (CDS) 7.2 and 7.3Easy-to-use software for reliable and efficient data analysis and control of chromatography instruments
SuppressionChemical onlyChemical & electrolyticElectrolytic suppressors require no regenerant, meaning there are fewer reagents to make, no acid exposure, and more consistent results
Column HeaterNoYes, optionalOffers increased precision and enables applications that run at elevated temperatures (including some basic EPA methods)
Eluent DegassingNoYes, optionalReduces baseline noise
Auxiliary ValveNoYes, optionalEnables automated sample preparation
Leak DetectionNoYes, built in optical sensorHelps with troubleshooting
Need more features for your ion chromatography? See our full ion chromatography offering.

Save even more with our academic pricing when you order your IC system online. Add a Dionex Easion IC System or Dionex Aquion IC System bundle to your cart and save 20% off your total order when you check out with promotion code P4598341. Please note, this promotion is currently available only in the U.S.

Online Ordering Information

How to redeem

  • 1. Add qualifying consumables to your cart at and enter the promotion code P4598341. The appropriate discount will be applied to the total price of chromatography consumables in your cart.
  • 2. If you need help selecting products for your applications, contact our team of experts at 1-800-332-3331 (option 2, then option 1).

* Required field

Style Sheet for Global Design System
Style Sheet for Komodo Tabs