How do particle size and flow rate affect normal-phase flash column chromatography?
Media particle size and solvent flow rate play major roles in chromatographic separations including flash purification. This is true in both reversed-phase chromatography (aka partition chromatography) as well as normal-phase chromatography.
The roles played are related to the overall compound mass-transfer kinetics and diffusion/dispersion as they migrate through the column. Smaller particles reduce sample dilution by reducing interstitial volume, while flow rate impacts the ability of molecules to efficiently pass through the porous particles.
In this post, I will show how both particle size and flow rate impact flash chromatography.
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How can I make purification of hard-to-separate compounds greener?
The planet’s population is growing, its resources are dwindling – this is a problem. On top of that environmental contamination from myriad sources is only compounding the issue of available clean food and water.
As chemists, we contribute to this issue, to some degree, by performing reactions that generate chemical waste in the form of unwanted by-products and excess solvents from work-up and purification. What can we, as chemists, do to help reduce our so-called “carbon footprint”?
In this post, I discuss some ways to improve flash chromatography resource utilization, especially for hard separations.
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So, which detector should I use for flash column chromatography?
In my role as senior technical specialist at Biotage I am often asked about compound detection options. For most flash chromatography methods, UV is the default detection tool since a majority of compounds do absorb some UV light.
Diode array UV detectors provide chemists choices in wavelength selection, providing the ability to widen or narrow the wavelength range needed to detect specific compounds and enhance their sensitivity.
When diode array detectors fail to detect compounds, it is because the compounds have no chromophore, e.g. carbohydrates, low extinction coefficients, exist in really low concentrations, or any combination of these. In these situations, alternative detectors are quite beneficial. In this post I will discuss a couple of detector options for flash chromatography.
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5 Steps to successful flash chromatography
The bane of organic synthesis for most chemists is purification rather than synthesis. Synthetic reaction mixtures are rarely devoid of impurities so some type of purification is necessary. Most often flash chromatography is used but for many chemists, it is less well understood than their chemical reaction and provides some level of anxiety.
In this post, I will summarize the five most important steps to creating a successful flash chromatography method and thus the anxiety associated with it.
How does solvent choice impact reversed-phase flash chromatography separations?
I have recently posted on how solvent choice influences the separation of hard to resolve compounds using normal-phase flash chromatography. As a chemist with an inquiring mind, I thought I would expand my research beyond normal-phase and see what happens in reversed-phase.
In this post, I share my results.
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How to efficiently scale-up flash column chromatography
For synthesis and medicinal chemists, compounds are typically made only once en route to a final product. Once that compound shows activity toward a particular target, then the synthesis is scaled up meaning that purification too requires scaling. The same is true in natural product research where once a high-value compound is isolated at small scale, there is a need to isolate it at larger scale.
Both of these scenarios can be problematic to scale-up/ process chemists when other, non-chromatographic purification techniques are not successful. When this happens, either a different synthetic route or extraction process is needed or large scale chromatography is employed. In this post, I will explain how flash chromatography can be successfully scaled while minimizing time and solvent consumption. Continue reading How to efficiently scale-up flash column chromatography
How can I rapidly remediate THC from CBD in my hemp extract using flash column chromatography?
Tetrahydrocannabinol, aka THC, is a hallucinogen found in cannabis and, to a lesser degree, in hemp. Though THC is legal in some locations in the US and Canada, there is a growing market for its non-hallucinogenic cousin, cannabidiol (CBD), which has purported medical benefits.
The problem with isolating CBD from cannabis and hemp is contamination from THC, which is typically present at a moderate to high percentage. In this post, I will provide some insight into rapidly purifying CBD to remove THC. Continue reading How can I rapidly remediate THC from CBD in my hemp extract using flash column chromatography?
How many times can I reuse my flash chromatography column?
Flash chromatography – a purification tool for both organic chemists and natural product researchers. This tool is essential when you need to remove impurities from your targeted product, or products, in order to get them pure. To reduce the costs associated with flash chromatography, some chemists try reusing the same column over and over, not always with success.
A question I am frequently asked is “how many times can I reuse my flash column?” Although I have previously addressed this topic, I feel it is worth another look. In this post, I will attempt to address this question by providing a bit more science behind the cartridge reuse question.
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