Chromatography Forum

Hello everyone, I am writing to this forum because I have a problem with an LC-MS, specifically with a FlexCube module. The equipment is a 6410 and the Flexi module model is a G4227A 1290 FlexCube, which has 2 SPE online cartridges. The problem is that with each injection that the equipment makes, the pressure increases by 3 to 5 bars. As a result, at the end of a sequence, the pressure has increased by 100 bars compared to the initial pressure. Also, when the pressure increases so much, the peaks start to become deformed and the column is damaged. And if you try another method that does not use the FlexCube, the pressure remains stable, but for this type of samples we need to use the cartridges.
All the parts of the module and the capillaries have been replaced and we do not know what else to try.

Thank you.

Hi

I'm not familiar with that system but for me this sounds like column blockage.
Is/may anything precipitating on the SPE cartridges?
Are the eluents for SPE and analytical cycles compatible? (-> precipitating salts)

From the flow path shown in the Agilents manual, the SPE catridges are backflushed to the analytical column. So you may add a pre-column or just inline-filters to protect your analytical column and just replace that after a certain number of injetions.
Or if possible adjust the connections so that the SPE cartridges are not backflushed so that the build up is kept on the SPE cartridge.
I don't know if it would be possible to backflush the SPE for cleaning and equilibrate prior to the next load cycle. (may need an additional pump and or valves?)