United Science CarbonX HPLC Columns



CarbonX HPLC Columns

We sell both COS and BOS HPLC Columns.

United Science recently developed a series of novel carbon modified porous silica materials for use in analytical and
preparative separations, and as solid-phase extraction media. The analytical materials exhibit unique characteristics
compared to other commercially available carbon phases as they are substantially more stable at high pressures and
exhibit acceptable mass transfer characteristics. Users of carbon-based phases are aware that some compounds are
very difficult to elute from existing commercial carbon-based materials. The new materials described here address this
problem through both the ability to adjust the carbon loading on the underlying substrate, and by using a relatively
inert substrate.

COS Key Characteristics

  • Carbon Coated Type B Silica.
  • Available in a variety of pore sizes and particle sizes.
  • Unique Selectivity for Isomers, Polarizable Analytes.
  • High Mechanical Stability.

BOS Key Characteristcs

  • Carbon Type B Silica.  Less retentive than COS.
  • Available in a variety of pore sizes and particle sizes.
  • Unique Selectivity for Isomers, Polarizable Analytes.
  • High Mechanical Stability.

Column Options

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CarbonX HPLC and Guard Columns

There are over 600 commercially available reverse phase columns.  Selectivity characteristics are what make them different.

For example, a C18 column can separate on the basis of hydrophobic interactions but could never separate geometric isomers. \

In general, CarbonX has unique selectivity for:

- Geometric isomers

- Polar, hydrophilic analytes

-Hydrogen bond donors

These characteristics allow it to retain sugars, metabolites, and other hydrophilic compounds under reverse phase conditions.

It is generally thought of as a way to improve the selectivity in SFC.

The plot to the right shows the Snyder Dolan Chromatographic Selectivity Parameters for Ionizable Compounds.

For more information, please download our poster HERE.


Are you using a Hypercarb phase now and are having some success?   Here are key features of CarbonX HPLC phases that make CarbonX similar but different:


-CarbonX has similar selectivity compared to Hypercarb.  (geometric isomers, polar hydrophilics, hydrogen bond donor selectivity)

-Very different in overall selectivity when compared to C18


- CarbonX has a range of pore sizes ( 80, 100, 300 angstroms available)

- CarbonX is UHPLC compatible  (Stable up to 20,000 psi with particle sizes down to 2 microns)

- CarbonX has 5-10% carbon vs Hypercarb which has 100% carbon so your analytes will elute.

- CarbonX is comprised of  layers of carbon on silica substrate vs pure carbon substrate

- CarbonX is available in superficially porous format for ultra high efficiency


The answer is, you can try.  But, it wont work.

In 1989, Knox an Kaur suggested that there are certain criteria for acceptable stationary phase packing materials.  They include:

- Availablity of various monodisperse, spherical particles

- Proper pore structure that is stable f(pressure) for acceptable analyte diffusion characteristics

- Adequate porosity and high specific surface area

- Good mechanical strentgh to withstand high pressure up to 20,000 psi

-Good chemical stability and homogeneity

Industrial carbon do not meet these requirements.