Conditioning involves establishing a flow of carrier gas through a column and the heating the column to drive off contaminants. This makes the column fit for analytical use. This step is crucial to the optimal performance of any analytical method.
Note: It's essential to follow the manufacturer's instructions and your lab's specific protocols, as some steps may vary depending on the type of GC and column you are using.
Column Installation and Preparation
- Ensure that the GC column is properly installed in the oven.
- Connect the column to the injector side, the detector end may be plugged with a No-hole ferrule and capillary nut initially and then the column can be connected to the detector end.
- Check for any leaks in the column connections.
Purging
Purge the Column and entire GC system with a carrier gas (commonly helium or nitrogen). Purging will remove all traces of oxygen and moisture from the injection port and column, which must be done before you heat the column. This typically takes 15-30 minutes.
Isothermal Conditioning
If you are using an isothermal method, hold the conditioning temperature for a specified period which can range from 30 minutes to an hour, or as specified by the column manufacturer.
Temperature Program
If your method involves temperature programming, create a temperature program that gradually increases the column temperature from the initial conditioning temperature (say 50°C) to the maximum operating temperature and hold for specified time for the baseline to be stable. Follow your specific method's temperature ramping requirements. If the baseline is still gradually falling after 1 hour consider extending the hold until a stable baseline is achieved. If using longer columns (> 30 m) or with thicker stationary phases (> 0.5 µm) conditioning may take longer due to the increased amount of stationary phase present.
Check Detector Stability
Monitor the detector signal (e.g., FID, TCD, ) to ensure it stabilizes. This indicates that the column is adequately conditioned and ready for analysis.
System Suitability Test
Run a system suitability test to confirm that the column meets the required performance criteria. This may include testing resolution, retention times, and peak shapes.
Sample Analysis
After successful conditioning and system suitability checks, you can start your sample analysis. Ensure that your samples are appropriately prepared and follow your analysis method precisely.
Maintain and clean your GC system, including the column, regularly to maintain long-term performance and avoid column degradation.
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