Troubleshooting MCGV Cross Port Leaks in Quaternary Pumps

This Information Applies To: Agilent 1100, 1200, 1290, and 1260 Quaternary Pumps

Issue

The Multi-Channel gradient valve may create pressure fluctuations and retention time shifts due to cross port channel leaks. To check if there are cross port leaks in the MCGV, the "bubble test” is an easy and quick way to confirm it. 

The cross port leak will result in solvents from unintended channels to mix with the mobile phase and will result in retention time shifts as well as pressure fluctuations.

Steps to Follow

1. While pumping from each channel, raise the solvent filters above the liquid to introduce an air bubble in each line. Allow it to go past the bottle cap and on the downward slope of the solvent line.
2. Place the bottle filters back into the solvent in each bottle. It’s a good idea to mark the bubble in each line with a sharpie or tape. If using a piece of tape, suggest marking the top of the air bubble to make it easier to see if it moves.
3. While pumping at 1 ml/min from channel A, look for movement of bubbles in the other three lines. If the bubble moves past the mark or tape in the other three lines, it means you have cross port leaking of that valve in the MCGV.
4. Repeat the process for 100% B, 100% C, and 100% D. Look for bubble movement each time to indicate MCGV cross port leaks.

If the cross port leak is determined, contact your local Agilent Support Representative for further support.

Learn how to effectively use your Agilent Multi-Channel Gradient Valve: Good practices for use of the Multi-Channel Gradient Valve in Agilent quaternary pump modules  on Agilent Community