Chromatography Forum

Hi everyone,

I have a problem when switching the method from Waters HPLC system to UPLC system for PAH analysis. When analysing the sample (dissolved in 100% acetonitrile and filtered thru 0.2um filter) using the UPLC system (with initial gradient of 50/50 ACN/water), the tubing is clogged easily, probably because of the precipitation of some matrices in the sample (in ACN) when mixed with the mobile phase (50% ACN/water). However, I couldn't dissolve my sample in 50/50 ACN/Water at the start because some PAHs may not dissolve well in this solvent. Is there any solution for this? Please advice.

Hub

Have you verified that it is, in fact, the tubing clogging rather than the guard cartridge or column inlet frit?

Hi Tom,

No. However, what The set of columns used in UPLC is exactly the same as when I use in the HPLC. Thereofore it is just the wise guess. Also, after replacing some of the tubings, the pressure resumes normal.

Hub

Also, after replacing some of the tubings, the pressure resumes normal

That pretty much verifies that it's the tubing.

The first thing I would do is to install a 0.2 micron in-line filter immediately downstream of the injector. Those are designed to be easy to change.