Chromatography Forum

Hello,
I encountered an interesting problem when using Waters columns on Dionex Ultimate 3000.
Applying original analytical methods developed on Waters HPLC systems with Waters columns on Dionex HPLC I observed unacceptably poor peak shapes.
By changing the columns with similar ones from other types like Hypesil or Inertsil the peak shape improves.
The first thing I suspected was the improper fitting because of a specific column design.
However, changing the sample solution with mobile phase considerably improved the peak shape even by using the Waters column.

Has anyone had any experience with such problems?
Does anyone have some idea what might be the reason and how this problem can be overcome so that I can use the original methods on Dionex by using original Waters columns?

Thank you in advance!
Boyan Yordanov

If a change to your sample diluent resulted in better peak shape on any system, chances are that your original diluent was too strong for your A phase and that it worked on any particular LC was more or less just dumb luck. Stick to keeping your sample diluent weak relative to your initial mobile phase composition (this means A phase % organic > that of your sample diluent for reverse phase).

yes problem known to me too.

especially when the method was developed on an Alliance system (or older 717+ Injector).
These types of injectors are (by design) quite "robust" with injection of "bigger" or let's say normal volumes (10 / 20 µL) of high organic solvents (eg. like reference substance in pure methanol), even if the initial composition of mobile phase is high in water.

When transferring such methods to an Agilent 1200 system, we also observed peak distortion of the reference substance.
Lowering the organic content in the injection solution solved the problem.