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 columnA series of preparatory work is required before use to ensure its performance and accuracy of analysis results. The following are detailed preparation steps:
1. Instrument and system preparation
Confirm instrument status
Ensure that the power of the ion chromatograph is turned off, stop the delivery of eluent, and avoid operating under high pressure or flowing conditions.
Check if all components of the instrument (pump, sampler, detector, etc.) are connected correctly and if there is any leakage or looseness.
Record the usage duration, sample type, and cumulative injection frequency of the old column, providing reference for subsequent method optimization.
System flushing
Rinse the system with deionized water or appropriate rinsing solution to remove impurities and bubbles from the pipeline.
The recommended flushing time is 15-30 minutes, and the flow rate and pressure need to be stable to ensure the normal operation of the system.
2. Preparation of reagents and materials
Preparation of rinsing solution
Select the appropriate rinse solution based on the analysis requirements (such as sodium carbonate sodium bicarbonate solution commonly used for anion analysis and methane sulfonic acid solution commonly used for cation analysis).
Use high-purity reagents and ultrapure water (conductivity less than 1 μ S/cm), and remove dissolved gases by ultrasonic degassing or online degassing device.
Preparation of other reagents
Prepare a standard solution for calibrating the instrument, with a concentration range that covers the possible ion concentrations of the sample.
If modification of the washing solution is required, an appropriate amount of organic solvent (such as acetonitrile or methanol, usually less than 50%) can be added.
3. Column Installation and Handling
Pre-installation preparation
Ensure that the chromatography column and instrument flow line are filled with ultrapure water or eluent before connecting, to prevent air bubbles from entering.
Connect according to the liquid flow direction marked on the column, ensuring that the sealing ring is correctly placed to prevent liquid leakage.
Column activation and equilibrium
The new column needs to be rinsed with a low flow rate of eluent (such as 0.3mL/min) for 15-30 minutes, gradually adjusted to the recommended working flow rate of 5.
If organic solvents are used for modification, they need to be added to the eluent and thoroughly mixed.
4. Environmental and operational condition control
Environmental Requirements
The temperature should be controlled between 15-30 ℃ (a column temperature box is recommended when the column temperature is 35 ℃), and the humidity should be below 85%.
Keep the laboratory clean and avoid dust pollution.
Power and Safety
Ensure stable power supply (voltage fluctuation within ± 10%), it is recommended to equip with UPS2.
When handling organic solvents, keep them away from sources of ignition and store them in a cool and ventilated place.
5. Sample pre-treatment
Filtration and dilution
The sample needs to be filtered through a 0.22 μ m membrane to remove particle impurities; If the concentration is too high, it needs to be diluted appropriately by 34.
Complex samples may require pre-treatment steps such as digestion, extraction, or centrifugation.