ACE HPLC columns are designed to meet even the most challenging of chromatographic applications, giving excellent performance with acidic, basic and neutral molecules. A wide range of particle sizes, pore sizes, bonded chemistries and column dimensions are available.
Ultra-high purity, ultra-inert ACE columns also provide unmatched reproducibility and excellent column lifetime. Independent comparison tests show ACE HPLC columns give outstanding performance.
ACE columns are available in capillary through to preparative dimensions, with a wide range of particle sizes (3, 5, 10 and 15μm), pore sizes (100Å and 300Å) and surface chemistries (C18, C8, C4, CN, Phenyl,AQ, C18-HL and SIL).
Significant differences in efficiency, peak shape and selectivity are observed when analyzing basic molecules. Increased tailing and retention are indicative of | undesirable secondary interactions between the test probes and silanol groups on the stationary phase surface. These interactions can also result in poor column reproducibility.
ACE HPLC columns were independently tested and found to be the highest efficiency, most inert columns available – making them the #1 choice in the development of reproducible HPLC methods.
We recommend starting most method development projects with C18 or C8, knowing that if more retention and hence more resolution is needed, your next choice is C18-HL (Hi-Load). Starting with C8 offers the benefit of shorter analysis times and/or lower organic solvent use. The elution order for most compounds will be the same on the aliphatic (C18, C8, C4) phases. If a different elution order is required for compound verification or to resolve matrix components, changing to a phenyl or CN phase is far simpler than trying to change selectivity by mobile phase changes. In many cases, the ACE CN and ACE Phenyl phases will offer a significant difference in selectivity from the aliphatic phases. ACE AQ is particularly recommended for applications requiring high aqueous content mobile phases. Improved resistance to phase collapse is seen compared to standard C18 phases.
The availability of a range of phases enables complete method optimisation. Figure 4 demonstrates the alternative selectivities shown for a series of closely related tricyclic antidepressants. The C4, C8 and C18 phases show the expected increase in hydrophobic character without a major change in solute selectivity. However, significant changes in polar selectivity are clearly demonstrated with both cyano and phenyl phases. Traditionally, C18 or C8 bonded chemistries have been preferentially used in the majority of applications, in part reflecting the lower stability of cyano or phenyl bonded phases. However, for a number of reversed-phase separations of polar compounds these latter materials provide the best selectivity. Within the ACE range of phases, all materials show comparable excellent stability and robustness. Hence for any application the column showing optimum selectivity can be chosen without the previous limitations of bonded phase stability.
