I am currently using the following Method for Analysis of Bromhexine. What Column and / or Alternative Method Conditions can you suggest? Mobile phase: 20:80 Potassium di-hydrogen Phosphate Buffer (Potassium di-hydrogen phosphate 1.0g, add 900ml DI Water, then change pH to 7.0 with 0.5mol / L NaOH Solution, and dilution it to 1000ml with DI […]
Reversed Phase & Aqueous Normal Phase Method Tips: 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 pair agent is recommended to increase retention and reduce peak tailing. Here, […]
How can I reduce tailing for Atomoxetine, Reboxetine, and Maprotiline in a Reversed Phase C18 HPLC method? – FAQ
How can I reduce Tailing for Atomoxetine, Reboxetine, and Maprotiline in a Reversed Phase C18 HPLC method? I am using a pH 4 Phosphate/Acetic Acid Buffer. Atomoxetine, Reboxetine, and Maprotiline all have Amine Groups. Standard C18 phases may have Residual Silanols on the surface which can interact Electrostatically with the Amines from these analytes. These […]
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 flow rate. Then it is best to inject a known standard and repeat the injections until duplicate chromatograms are […]
My method uses an ordinary type-B silica based HPLC column. Is there a Cogent TYPE-C™ column equivalent substitute?
While many columns use the same nomenclature for their stationary phases such as C18, phenyl, C8 etc, every brand of column has unique properties and in any given method, columns can perform equally and then in another method perform differently. It is the philosophy and belief of MicroSolv Technology Corporation that our Cogent TYPE-C™ columns […]
Using Two Columns and two Modes of HPLC Together If you connect the Cogent Bidentate C18™ & Cogent Diamond Hydride™ columns in parallel, but use the same mobile phase program on both columns, it will be difficult to have both Reversed Phase and Aqueous Normal Phase (ANP) modes operating simultaneously, therefore you will not get […]
The biggest difference is the silica surface and how it will benefit the user. The main difference in the silica’s is the dominance of Silicon-Hydride (Si-H) groups on the TYPE-C™ products instead of the Silanol Group (Si-OH) common to all irregular, type A & B silica based previous phases. This difference in polarity and the […]
Why use buffers during analysis and acid buffers such as the phosphoric acid for column storage solvents for Bidenate C18 columns? Will phosphate precipitate in the column?
The Cogent Bidentate C18™ phase can be stored in un-buffered aqueous / organic solvents, but flowing significant bed volumes of un-buffered aqueous will cause a drop in efficiency of approximately 35% before reaching a new steady state. This is why we recommend either acid or basic buffers but not un-buffered eluents during analysis. For storage […]