||ANP HPLC Replaces HILIC - With Benefits
Many chromatographers have been given the task to develop HPLC and LCMS methods for polar compounds. Those who have chosen HILIC columns often report their gradient methods are problematic causing them…
||EDTA plasma samples for creatine & creatinine - Blog.
Since we have done work with creatine and creatinine in urine, see appliction note we been asked about measuring levels of these compunds in EDTA plasma samples. It should be possible unless there is…
||Fosetyl-aluminum analysis tips by HPLC
You can use the Cogent Bidentate C18™ column in reversed phase (RP) with a high water content method. According to a 2014 third-party research article, if the analysis is done by reversed phase an ion…
||How can I reduce tailing for atomoxetine, reboxetine, and maprotiline in a reversed phase C18 method? I am using a pH 4 phosphate/acetic acid buffer.
Atomoxetine, reboxetine, and maprotiline alll have amine groups. Ordinary C18 phases may have residual silanols on the surface which can interact electrostatically with the amines from these analytes.…
||How can I separate methacrylic acid and dodecyl benzene sulfonic acid?
Good retention and peak shapes have been observed for similar compounds. Methacrylic acid is similar in structure to acrylic acid, which can be well-retained with a mobile phase of DI water + 0.1% formic…
||How do retention and efficiency of glucosamine compare using 4um vs. 2.o™ Cogent Diamond Hydride™ HPLC columns?
Glucosamine can be retained using an ANP gradient method with the Cogent Diamond Hydride™ HPLC column. Using either 4um particle size or 2.o™ (2.2um) columns did not affect retention times but efficiency…
||How to analyze phosphorylated compounds with the Cogent Diamond Hydride™ column
Phosphorylated compounds can be difficult to analyze by HPLC. However, a wide variety of compounds with the phosphate functional group have been able to be retained with the Cogent Diamond Hydride™…
||How to condition Cogent Type-B columns for storage
Long Term Storage: Rinse the column with 8 column volumes with pure solvent that you use as your mobile phase. It is important to use non-buffered mobile phase. Then purge the column with 8 column volumes…
||Hydrophilic & Hydrophobic peptides analyzed by LCMS in ANP
The Cogent Diamond Hydride™ HPLC columns using aqueous normal phase (ANP) chromatography are very good choices for LCMS or HPLC analysis of most peptides. We have published an article on peptides demonstrating…
||Types of isomers and suitable HPLC columns for separation
There are many types of chemical isomers, and each may require different approaches to obtain chromatographic separation. Some examples are as follows: Empirical Isomers: These compounds have the same…
||Use a Cogent TYPE-C™ column to develop methods instead of columns you have experience with many benefits?
There are many reasons to use Cogent TYPE-C columns for new methods. Below are some of the reasons and attached is a White Paper that provides a concise argument. Often gradients are required to cope…
||Using different Cogent™ stationary phase materials for different selectivity
Each of the Cogent™ stationary phase materials has a different bonded ligand and therefore potential for different selectivity of given analytes. Consider the example, featuring the Cogent Bidentate…
||Using temperature changes for separations of terpenoids with the Cogent Bidentate C18 and Cogent UDC-Cholesterol HPLC columns
Temperature is a useful variable to consider in HPLC separations. Control of temperature can reduce run times, alter selectivity, and change analyte efficiency. In this study of three terpenoids (bexarotene,…
||What are the main differences between HILIC and Aqueous Normal Phase?
There are many important differences between HILIC columns and Cogent TYPE-C Silica™ columns but for the sake of brevity, we will only address the main differences. The Cogent TYPE-C™ silica columns…
||What can you recommend for a bromhexine assay method?
Question: I am currently using the following method for analysis of bromhexine. What column and/or alternative method conditions can you suggest? Mobile phase: Potassium dihydrogen phosphate buffer(take…