HPLC LC-20 problems with normal phase chromatography

[Juan_Micha]

Hi! I'm new in this forum and have a question for you.
Anywone have problems with LC-20 model chromatograps and normal phase chromatography?
I detect many problems of baseline stability in this type of runs.
Thanks in advance.
J

[Vlad Orlovsky]

What is your mobile phase, system type, detection technique?

[Kwet80]

Effectively, we need more details...

But I can already say that normal phase solvent (hexane, propanol, THF, dichloromethan,...) can need specific tubing or seal. Look at the supplier's manual.

Take care to eliminate all traces of water in your system before aplying apolar solvent (pump, column, washing solvent, detector, all tubing lines). Use a transition solvent (soluble in both water and hexane: isopropanol, ethyl acetate, dioxane, THF or ethanol) between water and apolar solvent.

Take care of water solubilized into solvent like acetonitrile, ethanol, methanol, ethyl acetate.

Use miscible solvent.