HPLC Column, Bidentate C8, 4um, 4.6mm ID x 250mm Length, 100A. Cogent TYPE-C Brand. 1 EA.
Additional Info:
The 40008‑25P Cogent Bidentate C8™ HPLC Column is a long‑format analytical reversed‑phase column engineered for separations requiring maximum resolution and extended retention. Built on Cogent TYPE‑C™ silica hydride technology, this column delivers excellent selectivity, faster equilibration, and extremely robust column lifetimes compared with conventional silica‑based C8 columns.
The stationary phase consists of an aliphatic C8 hydrocarbon chain bonded via two direct silicon–carbon bonds (bidentate attachment) to a silica hydride surface. This non‑traditional chemistry produces a phase that is more hydrophobic than standard C8 columns, yet less hydrophobic than Bidentate C18™, making it an ideal choice when C18 columns retain compounds too strongly, but stronger retention than conventional C8 is still needed. Unlike traditional silica‑based C8 phases, this column can also retain select hydrophilic compounds, expanding the method‑development window.
The 250 mm column length provides the highest plate count and resolving power in the standard Bidentate C8™ analytical lineup. This makes the column especially useful when closely related compounds, isomers, or complex mixtures require additional separation space, or when longer retention times improve selectivity.
The column is also stable at very low pH (below pH 2) without degradation, enabling aggressive analytical conditions that are not suitable for conventional silica‑based C8 columns.
Why Choose the 4.6 × 250 mm Bidentate C8™ Format
This column size is commonly selected when:
Maximum analytical resolution is required
Shorter columns (50–150 mm) do not sufficiently separate critical pairs
Longer retention improves separation of complex mixtures
C18 columns provide excessive retention or slow analysis
The extended length increases interaction time and separation efficiency, while TYPE‑C™ silica hydride chemistry maintains fast equilibration and long column life.
Key Features
Cogent TYPE‑C™ Silica Hydride Technology
Non‑traditional reversed‑phase surface chemistry
Reduced silanol activity and secondary interactions
Faster equilibration than conventional silica‑based C8 columns
Extremely robust and reproducible performance
Bidentate C8™ Bonding
Two‑point attachment via direct Si–C bonds
Balanced hydrophobic retention
Alternative selectivity when C18 is overly retentive
Maximum‑Resolution Analytical Geometry
4.6 mm ID × 250 mm length
Highest resolving power in the family
Ideal for complex and closely eluting compounds
Broad Method Flexibility
Stable at very low pH (below 2)
Compatible with aqueous‑rich mobile phases
Suitable for aggressive and unconventional analytical methods
Typical Applications
High‑resolution analytical HPLC
Separation of closely related compounds and isomers
Complex mixture analysis
Situations where C18 retention is excessive
Method development and confirmatory analysis
Low‑pH reversed‑phase methods