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... from AkzoNobel

Kromasil® EternityTM- designed for longer column life, even under extreme pH conditions

Kromasil Eternity is based on a proprietary grafting technology, whereby the 100Å bare silica is modified by bonding with an organosilane layer. Under specific proprietary conditions, the organosilane layer penetrates the silica, which results in a merged organic/inorganic interfacial gradient. The pores are virtually returned to their original size resulting in a surface presenting both inorganic (-OH) and organic (-R) silicic acid moieties. It is this process step which gives Kromasil Eternity its extreme chemical stability, extending the pH range and column lifetime. This modified silica is then functionalised with monofunctional C18 or PhenylHexyl, followed by a proprietary endcapping process.
Kromasil Eternity Phases


Particle Size (μm)

Pore Size (Å)

Surface Area (m2/g)

Carbon Load %


pH Range


2.5, 5





1 - 12


2.5, 5





2 - 12

pH Variation in Method Development
The wide pH range offered by Kromasil Eternity enables greater selectivity flexibility when analysing ionisable compounds. Even under harsh pH conditions, Kromasil Eternity columns show long lifetimes. The test mixture used in Figure 7 contains a neutral, an acidic and a basic compound. Under alkaline conditions, the basic procaine is retained more than 3-nitrobenzoic acid. At pH 2.1, 3-nitrobenzoic acid is retained more than the other compounds. These changes in relative retention provide useful method development options.
Scale-up and Scale-down
Kromasil Eternity C18 and PhenylHexyl are available as 2.5 and 5μm particle sizes. These cover a wide range of applications, including classical analytical HPLC using 5μm in 250mm length columns and rapid HPLC using 2.5μm in 50mm length columns under both HPLC and UHPLC conditions. Kromasil Eternity is also a good choice for semi-preparative applications, due to its high efficiency and chemical stability. Figure 8 shows how easily a separation can be scaled down from 5μm to 2.5μm or scaled up to 21.2mm i.d. columns. Identical retention times are obtained despite the different particle sizes and column dimensions.

Contact Hichrom to request a Technical brochure:

Column dimensions available - Kromasil Eternity C18

Analytical Columns
2.5μm Phase Column Dimensions (mm)

50 x 2.1100 x 2.150 x 4.6100 x 4.6

5μm Phase


Column Dimensions (mm)


50 x 2.1150 x 2.1
50 x 4.6100 x 4.6150 x 4.6250 x 4.6

Semi Preparative and Preparative Columns
5μm Phase

Column Dimensions (mm)

50 X 10.0150 X 10.0250 X 10.050 X 21.2150 X 21.2250 X 21.2

Other column dimensions available on request.