Normal Phase

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SPECMA Si (USP L3)

Specma Si columns for Normal Phase and HILIC applications

Unmodified Silica gel materials were the first ones used for chromatography. This is the reason the mode is called "Normal phase" (NP). They are still used in HPLC, although Reversed Phase (NP) is by far the most often used HPLC mode today. A wide range of porous Si materials is available, characterized by:

  • Surface area
  • Pore size
  • Particle size
  • Purity
  • Metal content

SPECMA Amino / NH2 (USP L8)

Specma Amino columns for Normal Phase and HILIC applications

Amino (NH2) bonded silica gel phases can be used ideally in the normal phase and HILIC mode. They show alternative normal-phase selectivity to unbonded silica, especially for aromatics.

Amino columns can also be used in the HILIC mode for carbohydrate analysis and for other polar compounds. Their weak anion-exchange properties can be used in the analysis of anions and organic acids

Typically, the amino group is bonded to the silica support via a propyl linker. Most Amino phases shown here come without endcapping, only SPECMA Amino E is a fully end capped amino propyl bonded phase

SPECMA Diol / OH (USP L20)

Specma Diol columns for Normal Phase in HPLC and UHPLC

Diol packing material can be universally used in different polar modes (NP, RP and HILIC). Diol bonded phases are a versatile alternative to unbonded silica for normalphase separations with shorter equilibration times.

The hydroxyl groups provide good selectivity without excessive retention, caused by the weaker H-bonding of the diol layer than of silanols. Some diol bonded phases have been developed specifically for applications in the HILIC mode.

SPECMA Cyano / CN (USP L10)

Specma Cyano or CN for Normal Phase and Reversed Phase

CN (USP L10) is one of the most versatile stationary phases that can be used in reversed phase mode as well as in normal phase mode.

The cyano modification supports the pi-pi interaction as well as polar and hydrophobic interactions with low polarity solvents. These phases are preferred for compounds with double bonds and aromatic groups. Cyano bonded phases show unique selectivity for polar compounds and are more suitable than bare silica for normal-phase gradient separations. The cyano functional group is a strong dipole that can interact with other dipoles or induce dipoles on solutes. These phases also exhibit moderate hydrophobicity due to the alkyl linker.

Due to the quick equilibration time of the CN bonded phase, it is the best choice for gradient elution in normal phase mode. CN phases can be used as a less polar alternative to Si phases

The material is typically preferred for

  • compounds with double bonds and for
  • cyclic antidepressants.