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MicroSolv: Cogent TYPE-C Silica Phases

Cogent TYPE-C silica phases are formed from a high purity Type B silica backbone, which is modified to cover the silica surface with silicon-hydride (Si-H) bonds, thus replacing >95% of surface silanols (Si-OH). Using patented technology, bonded phases such as C18, C8, Phenyl, Cholesterol and Diamond Hydride are produced from the unique silica hydride surface with direct silicon-carbon bonds. These extremely strong non-polar bonds offer increased stability over traditional silica based phases.


Cogent TYPE-C columns can be used in three different modes of HPLC - classic reversed-phase, normal-phase with non-polar solvents and also normal-phase with aqueous solvents (Aqueous Normal Phase), in which analytes are retained on the basis of polarity. The surface silanols that are present in all Type A and B silicas, even after bonding and extensive endcapping, form a strong association with water, resulting in a ‘hydration shell' surrounding the silica. However, the silica hydride particles of TYPE-C silica are only slightly hydrophobic and therefore have a weak attraction for water allowing them to be used in ANP mode, which does not require a ‘water-rich' environment.
Cogent 2.o HPLC phases have a particle size of 2.2μm and show increased efficiencies compared to the 4μm phases.

  

The general features of Cogent TYPE-C include:

  • Use for 3 modes of HPLC - RP, NP and ANP
  • High efficiency columns
  • Polar and non-polar compounds
  • Fast equilibration between gradient runs

Cogent TYPE-C phase specifications

Cogent PhaseParticle
size (um)
Pore size (A)Surface Area (m2/g)Carbon
load (%)
EndcappedpH Range
Max. Temp. (°C)

Bidentate C18

4

100

390

18-19

No

2.0 - 10.0

80

Bidentate C18 2.o

2.2

120

340

20

No

2.0 - 10.0

80

Bidentate C8

4

100

390

13-14

No

2.0 - 8.0

80

Bidentate C8 2.o

2.2

120

340

11-12

No

2.0 - 8.0

80

Phenyl Hydride   

4

100

390

10-12

No

2.0 - 8.0

80

Phenyl Hydride 2.o    

2.2

120

340

9-10

No

2.0 - 8.0

80

Diamond Hydride

4

 100

390

>0.5

No

2.5 - 7.5

60

Diamond Hydride 2.o

2.2

120

340

2

No

2.5 - 7.5

60

UDC-Cholesterol

4

100

390

13-14

No

2.0 - 8.0

80

UDC-Cholesterol 2.o

2.2

120

340

13-14

No

2.0 - 8.0

80

UDA

4

100

390

14-15

No

2.0 - 8.0

80

UDA 2.o

2.2

120

340

14-15

No

2.0 - 8.0

80

Diol

4

100

390

9-10

No

2.0 - 8.0

80

Diol 2.o

2.2

120

340

9-10

No

2.0 - 8.0

80

Silica-C

4

100

390

0

No

2.0 - 7.0

60

Silica-C 2.o

2.2

120

340

0

No

2.0 - 7.0

80

Bidentate C8 300

5

300

100

5

No

2.5 - 7.5

80

Cogent Bidentate C18

has the C18 group bonded directly to the TYPE-C silica surface with two separate points of attachment. Columns are highly durable and suitable for use with 100% water or 100% organic solvent. These columns will retain the most polar compounds with a ≥70% organic content.

Cogent Bidentate C8

also has direct bonding to the TYPE-C silica surface with two separate points of attachment. This phase is less hydrophobic than the C18 phase but can also operate in RP, NP and ANP modes.

Cogent Phenyl Hydride

columns are an ideal choice for difficult to separate aromatic compounds. Due to the lack of endcapping, these columns do not exhibit ‘bleed', making them ideal for LC-MS analyses. Direct silicon-carbon bonds and the hydride surface enable long column lifetimes to be achieved.

Cogent Diamond Hydride

containing a low level of carbon on the surface, is a unique phase for the analysis of extremely polar compounds by Aqueous Normal Phase. It is a popular choice for the analysis of metabolites, underivatised amino acids, carbohydrates and small organic acids.

Metabolomics kits, containing one Cogent Diamond Hydride and one Cogent Bidentate C18 column, are ideal for LC-MS when searching for very polar and very hydrophobic compounds from serum, plasma, urine, saliva or any other biological fluid.

Cogent UDC-Cholesterol

has a liquid crystal attached to a silica-hydride particle and produces unique selectivity for many compounds, especially at lower temperatures. When used with methanol, Cogent UDC-Cholesterol has a selectivity mechanism based on shape recognition.

Cogent UDA

is a unique selectivity phase based on TYPE-C silica. The silica hydride surface is bonded with an eleven carbon chain terminating in a carboxylic acid (undecanoic acid), giving the phase weak cation-exchange properties in addition to ANP. Cogent UDA columns have applications in metabolomics and have been used for the analysis of nucleotides.

Cogent Diol

is suitable for reversed-phase or ANP analysis of polar compounds and is LC-MS compatible. Columns show fast equilibration between gradient runs and can be successfully used in studies of pathways in human pathology.

Cogent Bidentate C8 300

offers all the advantages of other TYPE-C columns, including a useful range of hydrophobic or hydrophilic compounds, long lifetime, resistance to TFA and other acids. The phase is designed for large molecules including proteins, peptides, polysaccharides and other polymers.

Literature:

  • Cogent Diamond Hydride ‘The Metabolomics Column'
  • Clinical Applications
  • Environmental and Food Applications
  • Pharmaceutical Applications

Further technical information:

See the Cogent pages in our catalogue


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