If you're new to HPLC, you might not think much about the degasser that quiet component hidden in your system.
But, degassing isn’t optional—it’s essential.
So, what does it do? And why does it matter?
Let's have an example:
Shake a soda bottle and try to drink it through a straw. The bubbles get in the way, right?
The solution?
A degasser.
A degasser removes dissolved gases (tiny bubbles) from the mobile phase line before it enters the HPLC system.
These gases may not be visible, but they can cause a lot of trouble:
1. They can form bubbles in the pump or detector and these bubbles can:
- Disrupt flow
- Cause pressure fluctuations
- Produce baseline noise or spikes in your chromatogram
2. They can interfere with how the mobile phase enters the detector leading to false signals or affecting baseline. (especially with UV and RI detectors).
3. Bubbles can compress and expand with pressure changes, causing flow instability, affecting retention time.
How Does Degassing Work?
- Most modern systems use an inline vacuum degasser with a semi-permeable membrane.
- Where the mobile phase flows through this gas-permeable membrane. While a vacuum draws out the dissolved gases through the membrane.
- The result is a bubble-free mobile phase.
Simple, efficient, and continuous.
Why You Should Care?
You might not notice poor degassing until your baseline starts drifting, your peaks lose shape, or your retention times vary.
So if any of these happen, it might be time to check your degassing.
Best Practices
- Always degas all aqueous solvents.
- Use ultrasonication if you don’t have an inline degasser.
- Don’t ignore degasser maintenance leaks or membrane damage can make things worse.
The degasser may be silent, but it's your chromatogram’s first line of defense.
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