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Reversed-phase HPLC columns have been widely used due to their superior resolution, high theoretical plate number, ease of use and good cost performance.
Octadecyl silica gel (C18, ODS) is the most commonly used by chromatographers. In reversed phase HPLC columns, hydrophobic interaction is the dominant separation mode. For some substances similar in hydrophobicity, recognition capability may be poor, resulting in insufficient separation.
The COSMOSIL PYE and NPE columns utilize various interactions based on electrons of the stationary phase. The PYE and NPE columns can be widely used for the separation of substances similar in structure.


The COSMOSIL PYE column is a reversed phase column. Its stationary phase is planar pyrene or 2-(1-pyrenyl)ethyl groups bonded chemically to the silica gel. Utilizing -interactions originating from the pyrene ring, the PYE column separates substances similar in structure.
The COSMOSIL NPE column is also a reversed phase column, which contains nitrophenylethyl groups chemically bonded to the silica gel. The NPE column provides unique retention characteristics somewhat different from the PYE column, utilizing both dipole-dipole and -interactions.

Stationary phases and interactions
Hydrophobic interaction
Charge transfer interaction
Stereo selectivity
Hydrophobic interaction
Charge transfer interaction
Dipole-dipole interaction

high purity spherical porous silica
Average particle size
Average pore size
approx. 120Å
Specific surface area
approx. 300m2/g
Stationary phase
nitrophenylethyl group
2-(1-pyrenyl)ethyl group
End capping treatment
near-perfect treatment
Carbon content
approx. 19%
approx. 18%

C18 columns have been commonly used for the separation of polycyclic aromatic hydrocarbons. However, their resolution for the separation of isomers is limited. Due to the electrostatic interaction between the sample (eg. benz[α]anthracene and chrysene) and the pyrene ring in the stationary phase, the COSMOSIL PYE packed column can achieve the separation of aromatic isomers.

Catalog # Cosmosil 5NPE Column Price ($U.S.) -
093-4500 5NPE - Analytical Column, 2.0 x 100 mm $824.00
093-4328 5NPE - Analytical Column, 2.0 x 150 mm $876.00
093-7902 5NPE - Analytical Column, 4.6 x 150 mm $876.00
093-7990 5NPE - Analytical Column, 4.6 x 250 mm $1,102.00
093-7991 5NPE - Semi-preparative Column, 10.0 x 250 mm $3,677.00
093-8046 5NPE - Preparative Column, 20.0 x 250 mm $11,938.00
093-7904 5NPE - Analytical Guard Column, 4.6 x 10 mm $412.00
093-8045 5NPE - Semi-preparative Guard Column, 10 x 20 mm $824.00
093-8112 5NPE - Preparative Guard Column, 20.0 x 20.0 mm $2,812.00
093-8111 5NPE - Preparative Guard Column, 20.0 x 50.0 mm $3,451.00


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