Chromatography Forum

I'm setting up a new HPLC and ran into some issues when I tried to equilibrate a brand new GL Sciences NH2 (150 x 0.3 mm, 3um) column. When I have the inline filter, guard column, and column connected I get relatively high pressures (~1800 psi), the inline filter leaks, and there is little to no flow coming off the column. I tried tightening the filter and the fittings connecting it but it made no difference. Then I removed the column and checked the flow through just the filter and guard column. In that case, the pressure is only ~50psi and the flow is normal.

I haven't run any samples yet. This has just been using 100% IPA to equilibrate the column. But I'm thinking there's either air or particles clogging the column?? Any ideas on how to remedy this situation? Would reversing the column and flushing it out work even if it means having a major leak from the inline filter??

I'm assuming that a 0.3mm Id on the column is a typing error (3 mm perhaps).

What flow are you running?
are you running at ambient or elevated temp?

IPA is quite viscous and I would expect quite high back pressures even with a 5µm phase moreso with 3µm. 2000 psi would not surprise me.

I'd remove/replace the inline filter if its leaking.

Please check the shipping solvent of your column. Maybe you need several intermediat solvents before using IPA as mobile phase.
Good luck.

Thanks for your responses! The 0.3mm is correct, I'm going to be working with dilute samples and need to limit the dilution from the solvent. It was shipped in hexane/ethanol and the directions were to begin equilibration with 100% IPA. The instrument I'm using does not allow for temperature control so I'm working at ambient conditions.

You did not specify the flow rate setting. From your description, it sounds like either the column is blocked or the flow is too high. In either case, the filter and guard should *not* leak at 1800 psi (as JGK indicated), so either one or both is defective or you have a misassembled fitting in there.

By the way, what are the dimensions of the guard?