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TYPE-C Silica Hydride HPLC Columns

1 Are Cogent TYPE-C Silica™ columns made with hybrid particles?

No, it is an evolution of standard, high purity, based deactivated, type-B silica with a very stable and unique surface that does not retain water as all other HPLC columns do. If you are using a commercially…

2 Are the Cogent TYPE-C Silica based stationary phases available as bulk materials?

No, the Cogent 4um and 2.o TYPE-C Silica™ based stationary phases are not available as unpacked bulk material. TYPE-C Silica™ is a very unique material and to properly pack columns or capillaries…

3 Can I use the Cogent Diamond Hydride™ column without mobile phase additives (e.g. formic acid)?

Using only acetonitrile and water and no additives is fully compatible with the column and will not damage it. We might however recommend having 0.1% formic acid during column storage to help inhibit…

4 Can you inject highly acidic samples on to Cogent TYPE-C Silica HPLC columns?

The Cogent TYPE-C™ Silica columns have certain specification ranges for pH that must be followed to avoid damage to the material. These specifications apply to the mobile phase eluent present in the…

5 Do I need to use a high mobile phase pH for compounds with a high pKa?

No, while some types of analyses for compounds have traditionally required a high mobile phase pH (e.g. up to 10, 11 or 12) in order to get acceptable chromatographic retention due to a high pKa, it is…

6 Do Tanaka Plots apply to Cogent TYPE-C™ Silica HPLC Columns?

To answer this question, first we must define what Tanaka plots are. Nobuo Tanaka devised a set of chromatographic tests that are intended to characterize the properties of a given stationary phase. The…

7 High pressure develops after flushing Cogent Diamond Hydride with acetonirile. Cause and solution.

Question: I was running a method using an ammonium acetate-based mobile phase and decided to clean the column. I flushed it with acetonitrile but noticed the column pressure was higher than before when…

8 How can I restore my Diamond Hydride HPLC column? I ran out of mobile phase in my B solvent and air was accidently introduced into it and my analytes are not retaining now.

Although you should never let any HPLC column dry out, your column is probably not ruined. However, It could take days to get it restored when conditioning it with your mobile phase. If there is air in…

9 How do I condition new Cogent TYPE-C™ Columns for use?

For all new Cogent TYPE-C™ HPLC columns with the exception of new Diamond Hydride™ columns, all one needs to do is run 7-10 column bed volumes of your mobile phase through the column at your normal…

10 How does a pulse from an HPLC pump affect the column and its performance?

If your HPLC pump produces a "pulse" (i.e. cyclic fluctuation in flow/pressure), this can cause problems for your method and column. The pump will not be delivering optimally precise/accurate flow and…

11 How does efficiency in ANP compare to HILIC?

Aqueous Normal Phase (ANP) is a distinctly different retention mode than Hydrophilic Interaction Liquid Chromatography (HILIC). In HILIC, evidence has shown that retention is achieved by partitioning…

12 How often do I need to clean the Cogent TYPE-C Silica columns?

It depends on the type of samples you are working with. The purpose of cleaning the column is to remove contaminants that build up on the column from your samples. As such, injecting clean samples such…

13 How to Condition Cogent TYPE-C Silica™ HPLC Columns for Storage

This article describes how to prepare the Cogent TYPE-C Silica™ columns for initial use when you first receive them as well as how to store them for either overnight or long-term to prevent column degradation.…

14 I am seeing changing retention times and a peak showing up in my blank using the Cogent Silica-C column in normal phase. What can be the issue?

It is most likely a matrix effect. You probably should wash the column first with a reasonable content of the strong solvent of your mobile phase, higher than at the end of the gradient. Then you should…

15 I am using a Cogent TYPE-C™column with LC-MS and solvents containing 10 mM ammonium acetate. I noticed that my source was getting white film on it. At the same time the background noise was very low. Is my column bleeding the packing material?

Cogent TYPE-C™ columns including the Cogent Diamond Hydride have a very low background noise even when used with LC-MS and the white film most likely comes from ammonium acetate build up from your mobile…

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