Ion chromatography columnIt is the core component of ion chromatography system, and its performance directly affects the accuracy and efficiency of chromatographic analysis. After the sample solution to be tested is injected into the ion chromatography system through a high-pressure pump, it is subjected to a pretreatment unit to remove large particle impurities and adjust the pH value of the solution, and then enters the ion chromatography column. In the chromatographic column, each ion is separated by ion exchange at different speeds under the influence of an electric field or mobile phase, based on its charge properties, ionic radius, and affinity with resin functional groups. Ions with weaker affinity are eluted first, while ions with stronger affinity are released later, forming chromatographic peaks of different ions on the time axis.
Ion chromatography columnMaintenance in daily use:
1. Control flow rate and pressure
To avoid sudden increases in flow rate or pressure, the pump should be gradually adjusted from a low flow rate (such as 0.3 mL/min) to the working flow rate when starting to prevent mechanical damage.
The working pressure should not exceed the upper limit of column tolerance (usually anion column ≤ 30 bar, cation column ≤ 20 bar).
2. Maintain a stable chemical environment
Requirement for rinsing solution: Use high-purity reagents and ultrapure water (conductivity<1 μ S/cm), and perform degassing treatment (ultrasonic or online degassing).
PH control: Avoid strong acid/strong alkaline conditions, such as pH range 2-12 for anion columns and 1-7 for cation columns.
Organic solvent limitation: If using modifiers such as acetonitrile and methanol, the concentration must be below 50%.
3. Sample pre-treatment
The sample needs to be filtered through a 0.22 μ m membrane to remove particle impurities; High concentration samples need to be diluted to within the linear range.
It is recommended to centrifuge or solid-phase extraction pretreatment for complex matrix samples to reduce the risk of contamination.
4. Regular flushing
After the analysis is completed, rinse the column with deionized water or low concentration rinsing solution for 10-15 minutes to remove residual salts or samples.
During long-term operation, perform a deep maintenance rinse every 100-200 injections (such as 0.01 M H ₂ SO ₄ or NaOH solution, refer to the column manual for details).