Chromatography Forum

Hi everyone,

I am going to use Phenyl column to develope a method. However a lot of people are saying "Pheny column is not good. So much trouble!" Can anyone explain why and what kind of typical problems using Phenyl column?

Thank you.

Maybe you should ask some of the "lot of people" what's not good with Pheny columns.
Accidentally - what mekes you choose this type of columns?

Best Regards

C18 -> C8 -> C4 -> C1 -> Phenyl
Strong retardation -> low retardation, so for compounds with very high RT on C18 it can make sence to try a Phenyl column. Most problems come from a long equilibration time, very sensitive to buffer changes.
Many years ago I was told that reproducibility is not good. But new generation of Phenyl columns are very reproducibel. But if a Phenyl column is recommended for your application a HILIC column should be tested as well.

C18 -> C8 -> C4 -> C1 -> Phenyl
Strong retardation -> low retardation, so for compounds with very high RT on C18 it can make sence to try a Phenyl column. Most problems come from a long equilibration time, very sensitive to buffer changes.

I would not approve the classification of phenyl columns in this sequence generally. You might be right when considering only hydrophobic interactions, but when pi-pi interactions come into play (and that's what phenyl is good for) phenyl vs. alkyl might look completely different. Then you migtht actually get more retention from phenyl than from C18.
Also, when long retention times are a problem, I'd rather stay with alkyl and go down to C8, probably C4, and not necessarily to phenyl. I usually try phenyl only when I just cannot get enough selectivity from C18.
Concerning longevity and reproducibility of phenyl, I'd say if you don't abuse your columns there's not that much difference anymore between good modern phenyl and C18 columns.

I agree with the last post. If you want to test a phenyl column for alternative selectivity to C18, use methanol rather than acetonitrile which can suppress pi-pi interactions.

Phenyl columns are just not generally as stable as C-18 or C-8 columns (or CN columns, in my experience). If you need a phenyl column, then obviously, use one. If you're developing from scratch, make sure you do some research about what others have used to come up with good separations of your compounds (or at least close relatives thereof) before reaching for a phenyl column.

Data point: I've had good luck using phenylhexyl columns and have not had any issues with short lifetimes. Early on they tend to bleed a little, but that seems to abate after a while. I've used Phenomenex Luna and Kinetix phenylhexyls with good success across a variety of applications and have never had a problem. Also, I find that they're about as retentive as a C8 or perhaps a C4 with a mid range carbon load with different selectivity (obviously). Treat your column well and it'll do the same for you.

CJ