c1d6df67_C18s_Are_the_Same_Aren_t_They___2
[0] C (2.8) [2] 
Silanol Ionisation at pH 2.8. At this pH, all residual silanol groups should be in the less active (un-ionized , vicinal) form. Any acidic silanols that have been activated (e.g. by metal ions in stationary phase support) remain charged and can have significant detrimental effect, particularly with excessive tailing of bases. More traditional phases tend to have high C (2.8) values, with resulting poor peak shape.
All HPLC C18s Are the Same Aren’t They?
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