For chemists, flash chromatography is part of their everyday synthesis workflow. For most syntheses, crude reaction mixtures are purified by normal-phase (aka adsorption) chromatography. There are times; however, where the crude mixture’s complexity and polarity make normal-phase chromatography very challenging. For these situations, reversed-phase (aka partition) chromatography may be a preferred option.
But, if you have only one flash system available, can you, should you, and how do you efficiently switch from non-polar, normal-phase solvents to polar, reversed-phase solvents – and back again without issues? In this post I’ll attempt to shed some light on the topic.
Continue reading How can I perform normal-phase and reversed-phase column chromatography on one flash system?
With most chromatographic purifications, only two solvents are needed to adequately separate compounds from each other. Unfortunately, there are instances where the separation is either poor or cannot be accomplished with “normal” elution conditions such as those with ionic or very polar organic molecules.
In this post I offer some solutions to this issue.
Continue reading Ionizable compound purification using reversed-phase flash column chromatography
In this post, I will look at the impact modifying mobile phase pH can have on reversed-phase separations.
Continue reading Using pH to optimize reversed-phase flash chromatography separations
Have you ever run flash column chromatography with mass detection (Flash-MS) and observed the total ion current or TIC increase during the purification only to find that there was no discernible compound contributing to the effect?
In this post I discuss how I came across this issue and the solution I found to work.
Continue reading How do I remove an annoying MS TIC background?