PAHs analysis by UPLC - tubings easily clog

[chhubert]

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

[tom jupille]

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

[chhubert]

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

[tom jupille]

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.