Chromatography Forum

Hello,

the mentioned columns are considered as very hydrophobic phases which are very suitable for the analysis of bases (low tailing).

Does anybody can tell me something about the robustness/life-time of one of these columns (including the mobile phase you use).

Thank you very much for each answer.

Kind regards

Florian

Neither is the Ace column terribly hydrophobic, nor is a good hydrophobicity a guarantee for good peak shape of bases. If you care about reproducibility, the best option in the entire world is Symmetry C18.

I think you will find ACE C18 "moderately" hydrophobic when compared to all C18 columns on the market. As Uwe said, hydrophobicity is no indicator of peak shape for basic compounds. You will find ACE C18 as one of the best for peak shape and efficiency. Even better than Symmetry

Regarding stability, ACE is as good as any silica based column available with respect to pH. Possible exceptions being hybrid silicas designed for high pH work. ACE C18 will give good usable life time between within the pH range of 2 - 8. Dirty samples and mobile phases, rather than pH, are the leading causes of column failure. For this reason, guard columns and pre-filters are recommended with all HPLC columns.

Carl Zimmerman

For difficult basic drug compounds, we recommend Unison UK-C8
or Cadenza CW-C18. Below are tricyclic antidepressents (using
HCOOH - no phosphates):

http://www.silvertonesciences.com/files/TI398E.pdf

As far as batch to batch reproduciblity goes - Imtakt has the data to support all
of their phases:

Cadenza CD-C18: http://www.silvertonesciences.com/files/TI008E.pdf
Unison UK-C18: http://www.silvertonesciences.com/files/TI124E.pdf
Unison US-C18: http://www.silvertonesciences.com/files/TI123E.pdf
Unison UK-C8: http://www.silvertonesciences.com/files/TI125E.pdf
Unison UK-Phenyl: http://www.silvertonesciences.com/files/TI126E.pdf
Unison UK-Amino: http://www.silvertonesciences.com/files/TI318E.pdf