Ion chromatography (IC) is a powerful analytical technique widely used to detect and quantify ions in water, food, pharmaceuticals, and more. But how does ion chromatography work step by step? Here’s a breakdown of the process behind this essential laboratory method.
Step 1: Sample Introduction
A liquid sample containing ions is injected into the IC system using an autosampler or manual injector.
Step 2: Ion Separation in the Column
The sample flows through an ion-exchange column packed with resin particles. These resins selectively attract and retain either anions or cations, separating them based on their charge and size.
Step 3: Elution with Mobile Phase
An eluent (a liquid mobile phase) continuously flows through the column, gradually displacing the retained ions. Different ions move at different speeds, leading to separation over time.
Step 4: Suppression (Optional but Common)
In many systems, a suppressor reduces background conductivity of the eluent, enhancing the signal of the ions being measured. This step is crucial for improving detection sensitivity.
Step 5: Detection
Separated ions pass through a conductivity detector, which measures changes in electrical conductivity and converts them into analytical signals.
Step 6: Data Analysis
The resulting data is processed by chromatography software, which generates a chromatogram—peaks representing the concentration of each ion present in the sample.
Ion chromatography is valued for its high precision, reproducibility, and sensitivity—making it a cornerstone technique in regulatory testing and quality control across multiple industries.
