NACALAI TESQUE, INC.

Reversed phase HPLC columns have been widely used because of their superior resolution, high theoretical plate number and ease of use. Since hydrophobic interaction is the dominant separation mechanism in reversed phase chromatography, conventional stationary phases such as C₁₈ and C₁₈ do not offer optimum selectivity for compounds with similar hydrophobicity. COSMOSIL offers a broad selection of columns with unique stationary phases for separation of these difficult analytes. These columns offer improved separation of structurally similar compounds that are difficult to analyze with a C₁₈ type column.

Material characteristics

Packing material	Cholester	πNAP	PYE	NPE	PBB-R
Silica gel	high purity porous spherical silica
Average particle size	5 μm
Average pore size	approx. 120A
Specific surface area	approx. 300 m2/g
Stationary phase	Cholesteryl group	Naphtylethyl group	Pyrenylethyl group	Nitophenylethyl group	Pentabromobenzyl group
Bonding type	monomeric
Main interaction	- hydrophobic interaction - molecular shape selectivity	-hydrophobic interaction -π-π interaction	-hydrophobic interaction -π-π interaction -dispersion force -charge-transfer interaction	-hydrophobic interaction -π-π interaction -dipole-dopole interaction	-hydrophobic interaction -dispersion force
End capping treatment	near-perfect treatment
Carbon content	approx. 20%	approx. 11%	approx. 18%	approx. 9%	approx. 8%
Feature	Usable under condition the same as C18 High molecular sharp selectivity	Stronger π-π interaction than Phenyl column	Strongest π-π interaction	Dipole-Dipole interaction	Dispersion force interaction

Column selection guide

• COSMOSIL Cholester
• COSMOSIL πNAP
• COSMOSIL PYE
• COSMOSIL NPE
• COSMOSIL PBB-R