Tel: +44 (0) 118 930 3660

Kromasil Eternity and Kromasil EternityXT

Kromasil Eternity and its newer extension EternityXT are designed for the separation and purification of compounds under reversed-phase HPLC and UHPLC, with an extended operating pH range of 2 to 12. These phases are based on proprietary grafting technology, whereby the Kromasil 100A base silica is modified with an organosilane layer. Under specific proprietary conditions, the organosilane and silica merge into an organic/inorganic interfacial gradient. The pores are virtually returned to their original size, resulting in a surface exhibiting both organic and inorganic moieties. It is this process step which gives Kromasil Eternity and Kromasil EternityXT their extreme chemical stability, extending the pH range and column lifetime. The modified silica is then functionalised with monofunctional C18 or PhenylHexyl, followed by a proprietary endcapping process.

For all new methods, it is recommended that the newer Kromasil Eternity XT columns are always used.

Kromasil Classic silica phases are ideal for preparative and process scale applications. In addition to high purity and excellent chemical stability, Kromasil silicas offer high mechanical strength and excellent scalability and loadability. Virtually seamless scale-up from analytical to preparative scale can be achieved.

  • Proprietary organic/inorganic layer
  • pH stable from 2 – 12
  • Long column lifetime
  • 1.8um Kromasil EternityXT phases for UHPLC
  • Fully scalable


Kromasil Eternity phase specifications:


Kromasil phaseParticles ize (um)Pore  size (A)Surface area (m2/g)Carbon load (%)EndcappedpH RangeUSP code

Eternity C18

2.5, 5 100 330 14 proprietary 1 - 12 L1

Eternity PhenylHexyl

2.5, 5 100 330 12 proprietary 2 - 12 L11
EternityXT C18 1.8, 2.5, 5, 10 100 280 18 proprietary 1 -12 L1
EternityXT PhenylHexyl 1.8, 2.5, 5, 10 100 280 15 proprietary 2 - 12 L11


Kromasil Eternity C18 and EternityXT C18 are designed for the separation of and purification of acids, neutrals and bases, whereas Kromasil Eternity PhenylHexyl and EternityXT PhenylHexyl provide alternative selectivity for compounds containing an aromatic ring.

The ability to use these phases up to pH 12 introduces greater flexibility for optimising large-scale applications. Many pharmaceuticals are basic and at low or neutral pH will be protonated, resulting in very low loadability. Analysis at high pH, where the basic pharmaceutical is neutral, enables significantly higher loadability, resulting in higher productivity. Large scale separations can be run for an extended time, even at pH as high as 12. Kromasil EternityXT 10um phases are ideal for such preparative applications


Kromasil Eternity Brochure

Kromasil Eternity PhenylHexyl


Kromasil EternityXT brochure


Further technical information: