Welcome to the Biotage Flash Purification Blogs.

      How important is your flash column’s plate count, aka efficiency, to your purification?

      October 29, 2019 at 5:00 PM / by Bob Bickler posted in Optimization, Media

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      Plate count is a theoretical number describing the separation efficiency of a chromatography column. In short, it is a measure an eluting compound's bandwidth at the time it elutes from a column, Equation 1.

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      What if you could use Semi-Preparative HPLC columns on your Flash Chromatography system?

      October 24, 2019 at 2:08 PM / by Panagiotis Ioannidis posted in Chromatography, HPLC

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      The newly released Biotage® Selekt flash chromatography instrument can be run at a maximum flow-rate of 300 mL/min or a maximum pressure of 30 bar. These high flowrates and pressures enable a user to perform chromatography using not only dry-packed, single-use plastic flash columns containing small (≥20 μm) spherical silica particles, but also semi-preparative, slurry-packed
      HPLC columns for multiple use with smaller (≤20 μm) spherical silica particles.

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      Biotage vs Biotage, and the winner is...

      October 23, 2019 at 9:28 AM / by Panagiotis Ioannidis posted in Chromatography, Optimization

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      When Isolera™ was launched, the maximum system pressure that could be reached was 10 bars, but reaching that pressure was a challenge since most of the Flash columns could not withstand the higher pressures. The maximum pressure rating for the Biotage® SNAP columns, for example, is limited to five or seven bars, depending on the size, and columns from most of manufacturers have the same limitation.

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      Which sorbents work best for dry loading flash column chromatography samples?

      October 18, 2019 at 10:05 PM / by Bob Bickler posted in Solvents, Media, Loading method

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      For chemists needing to purify natural product extracts or synthesis reaction mixtures flash chromatography is typically the tool of choice. In previous posts I have discussed various ways to optimize the purification to obtain the highest purity compounds with maximum load in minimal time.

      Sometimes, though, chemistry gets in the way in the form of solubility issues. When this happens most often dry loading is recommended for these sample types. In this post I will show the impact various dry load sorbent options have on chromatography.

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      Purifying ionic compounds by flash column chromatography

      October 18, 2019 at 10:00 PM / by Bob Bickler posted in Polar, Reversed-phase, Solvents

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      One of the more challenging purifications is that of water-soluble, ionizable compounds. Typically, normal-phase with silica is not used because of the probable non-reversible interactions, especially between the ionized amines interacting and the ionizable silanols.  With normal-phase out of the purification solution that leaves ion exchange and reversed-phase as chromatographic options.

      In this post I will discuss the use of reversed-phase and the influence pH and buffers have on the chromatography of some ionic, water soluble compounds.

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      Six key factors that impact flash chromatography

      October 18, 2019 at 9:54 PM / by Bob Bickler posted in Optimization, Solvents, Media

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      In this post I will delve into six key factors that impact your purification success in flash column chromatography.

      Previously, I have discussed the use of TLC for solvent scouting and method development and optimization. I have have also talked about cartridge size, particle size, and surface area and their impact on flash purification.  Here I integrate that information into the six factors below.

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      How do I purify my high boiling solvent reaction mixture using silica flash chromatography?

      October 18, 2019 at 9:48 PM / by Bob Bickler posted in Optimization, Solvents

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      Many chemists today find they need to synthesize molecules at higher temperatures in order to force difficult reactions to proceed. Solvents such as DMF, DMSO, and NMP are commonly used in these reactions as they facilitate the use of the high reaction temperatures.  However, the same attributes that make these chemicals attractive as reaction solvents make compound recovery from them very difficult, including flash column chromatography.  These high boiling solvents are typically polar and pose a challenge if purification is to be accomplished with normal-phase silica.

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      How does solvent choice impact flash column chromatography performance?

      October 18, 2019 at 9:44 PM / by Bob Bickler posted in Troubleshooting, Theory

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      Selectivity and solvent strength are the most important factors that determine success or failure of a chromatographic separation. These two independent dynamics apply to both normal- and reversed-phase chromatography and should be optimized, especially when high fraction purity is needed.

      In this post I will discuss the impact that elution solvent choice has on both normal- and reversed-phase purification.

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      Prep HPLC vs. reversed-phase flash chromatography: How to choose?

      October 15, 2019 at 5:02 PM / by Bob Bickler posted in HPLC, Normal phase, Reversed-phase

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      This question is one that is increasing in frequency. Over the past 10 or so years reversed-phase flash chromatography use has increased dramatically. Likewise, reversed-phase preparative HPLC (RP pHPLC) use has also increased. Chemists need to know when to choose between the speed and low solvent use of flash column chromatography and the ultimate purification of RP pHPLC. With this as the backdrop, let me give you my thoughts on how to choose between flash chromatography and when it is best to use RP pHPLC.

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      How does solvent choice impact reversed-phase flash chromatography separations?

      October 4, 2019 at 6:30 PM / by Bob Bickler posted in Cannabis, Chromatography, Gradient, Normal phase, Optimization, SNAP, Solvents, Troubleshooting, Selekt, Media, Mass-directed purification, Theory

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      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 do I choose between Normal- or Reversed-phase flash column chromatography for my compound purification?

      October 4, 2019 at 6:25 PM / by Bob Bickler posted in Normal phase, Reversed-phase, Solvents

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      How to choose between normal- and reversed-phase flash column chromatography is an excellent question and one that my readers often ask.  Those who use column chromatography know that as long as the reaction products or compounds are fairly non-polar and near neutral pH they will have successful purifications.  However, when your mixture's chemical characteristics are more challenging (polar, non-polar, basic, acidic) there are other options that are available to successfully separate pure compounds.

      In this post, I will discuss the criteria you can use to guide your choice between normal- or reversed-phase flash chromatography.

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      Acetone – a lower cost alternative to EtOAc in normal-phase flash column chromatography

      October 4, 2019 at 6:22 PM / by Bob Bickler posted in Normal phase, Solvents

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      Acetone, as you know, is a terrific solvent.  It dissolves many organic molecules, evaporates easily, is both water and organic soluble, and is cheap (relatively).  These attributes tell me it should be a good polar modifier for normal-phase flash chromatography.

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      When should I use dry loading instead of liquid loading with flash column chromatography?

      October 4, 2019 at 6:17 PM / by Bob Bickler posted in Chromatography, Small Molecule, Polar, Samplet(R), Synthesis, Workflow, Media, Loading method

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      Many microwave assisted organic synthesis (MAOS) reactions use polar solvents such as alcohols, DMF, DMSO, because they absorb and transfer microwave energy very efficiently.  However, the downside of using polar, microwave absorbing solvents is that they can interfere with normal-phase flash chromatography.

      In this post, I discuss why dry loading can be advantageous when purifying polar-solvated reaction mixtures.

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      Detecting the undetectable in flash column chromatography using wavelength focusing

      October 2, 2019 at 5:52 PM / by Bob Bickler

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      Sometimes it feels as if organic chemistry and chromatography are a mixture of art and science.  Maybe its because of the necessary creativity needed to address the variety of challenges that we face almost daily.  Frankly, its what I find most interesting about this world.

      One of the bigger challenges facing chemists is the ability to detect and collect compounds with little or no UV absorption during flash purification.  In this post I will talk about a technique that I have found to be quite useful when trying to purify mixtures containing one or more poor absorbers.

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      What is a Chromatography Gradient?

      October 2, 2019 at 3:27 PM / by Bob Bickler posted in Gradient, Optimization

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      Gradients, used in chromatographic methods, assist with chemical separation and elution. They begin with “weak” elution conditions and end with “strong” elution conditions.

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