- High efficiency and long life at high pH — up to pH 11.5.
- Unique bidentate bonding and double end-capping provides high pH stability.
- More efficiency and better peak shape than polymer-based columns.
- Improved retention, resolution, and peak shape of basic compounds.
- High sensitivity for LC/MS separations of peptides.
The Agilent ZORBAX Extend-C18 column uses a novel bidentate C18-C18 bonding technology to make it possible to develop high-resolution separations at high pH with a silica-based column. At high pH, noncharged basic compounds will not interact with the underlying silica. The result is high-efficiency separations with superior peak shape and improved resolution. High pH separations are also the best choice for compounds that are more stable or more soluble in high pH solutions. Some of the mobile phase buffer options for high pH include triethylamine, pyrrolidine, glycine, borate, and ammonium hydroxide. Ammonium hydroxide at pH 10.5 is an excellent mobile phase modifier for the LC/MS of peptides and small molecules with improved sensitivity, compared with TFA containing mobile phase at low pH. The Extend-C18 column is stable from pH 2-11.5 with good peak shape for all types of compounds. Extend-C18 columns also provide an additional selectivity choice at low pH.