ACE® CN-ES is a unique bonded phase that has an extended alkyl chain spacer with a terminal cyano group.  ACE CN-ES provides more hydrophobic retention and stability than other  cyano phases with shorter (usually n-propyl) spacers. 

ACE CN-ES UHPLC and HPLC columns retain and separate analytes via dipole-dipole interactions and enhanced hydrophobic interactions, and offer alternative selectivity compared to other phases for polar analytes.  ACE CN-ES columns can be used with 100% aqueous mobile phases in reversed-phase mode (RPLC), and remarkably, deliver excellent performance in normal-phase mode (NPLC).

The CN-ES phase provides alternate, orthogonal selectivity compared with other ACE phases such as ACE C18, ACE C18-AR, ACE C18-PFP, ACE SuperC18, and ACE C18-Amide.  When used in a systematic method development scheme, these highly selective phases can make the separation of complex samples much more efficient and effective.


  • Comparable retention and hydrophobicity to a C18 phase
  • Stable using low and mid pH eluents
  • Compatible with 100% aqueous mobile phases and can provide increased retention for polar analytes
  • Low bleed for UV and LC/MS compatibility
  • Fully applicable for normal-phase (NPLC) separations
  • Available in high-efficiency 2 µm, 3 µm, 5 µm and 10 µm particles for UHPLC, HPLC, semi-preparative and preparative separations
  • Excellent column choice for method development
  • Ideal for analytes containing double and triple bonds, and for analytes with polarizable functional groups or differing dipole moments.
  • Example analyte types:  acids, amines, alcohols, alkenes, alkynes, aldehydes, ketones, ethers, esters, halogenated compounds, nitriles, aromatic compounds, thiols, sulfides, etc.
  • Ideal for analytes that have inadequate retention on traditional cyano (CN) phases

Figure 1 ACE CN-ES Provides Increased Retention and Alternative Selectivity

In this example, ACE CN-ES provides significantly more retention than the shorter chain cyanopropyl phase (ACE CN), and it offers comparable retention but different relative retention compared to the ACE C18 phase.

Figure 2 ACE CN-ES: Excellent for Method Development

The ACE CN-ES phase is an excellent addition to your set of orthogonal columns used for method development. It can often separate analytes that co-elute on other phases or can reverse analyte elution order.

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