Welcome to the Biotage Flash Purification Blogs.

    Bob Bickler


    Recent Posts

    What is the smallest amount I can purify using flash chromatography?

    January 19, 2023 at 2:07 PM / by Bob Bickler posted in sensitivity, detection

    0 Comments

    Most often the question on loading is “how much can I purify” on a specific column size but once in a while I get the question above – what is the smallest amount I can purify? This is an interesting question, especially since flash chromatography is preparative chromatography technique used to purify large amounts of crude mixtures.

    Read More

    Why is Solvent Evaluation by TLC Important for Good Flash Chromatography Results?

    November 22, 2022 at 3:27 PM / by Bob Bickler

    0 Comments

    Organic chemistry can be messy with not only the desired compound created but also myriad by-products. As synthetic chemists, our goal is to make these desired compounds in sufficient yield and purity to either create another compound or submit for evaluation by other departments. To purify these reaction mixtures, flash chromatography is the primary technique.

    Read More

    How does a flash system’s internal volume affect gradients?

    November 8, 2022 at 9:21 PM / by Bob Bickler

    0 Comments

    For many years I have been publishing a blog on flash chromatography, especially related to its theory and application. It dawned on me today that one area I have not yet addressed is the impact of the flash system’s internal plumbing volume on a programmed gradient, so, here it is.

    Read More

    How does an acidic pH affect reversed-phase chromatography separations?

    November 1, 2022 at 2:19 PM / by Bob Bickler

    0 Comments

    Chromatography is as much an art as it is a science. Between synthetic reaction products and natural products, the range of compounds requiring separation, purification, and isolation is broad and diverse creating challenges from time to time. Because of this diversity, not all chromatographic separations can be performed with a “neutral” solvent system – one without added pH modifiers or buffers.

    Read More

    How should I make my linear gradient?

    October 11, 2022 at 2:20 PM / by Bob Bickler

    1 Comment

    Flash chromatography gradients need to provide as good of a separation between the target compound at its closest eluting by-products as possible in order to maximize product purity and load. Many chemists create methods based on a history with a compound class, knowing what has worked in the past. If no history with a synthetic compound class exists, then methods need developing.

    Read More

    What is a step gradient and why should I use it?

    September 27, 2022 at 2:07 PM / by Bob Bickler

    0 Comments

    Most chemists I meet utilizing flash chromatography use linear gradients. These gradients are either very generic (X% to Y% over a certain time or volume) or can be complex with multiple slope changes and even isocratic holds. These complex gradients are often created during a purification to get the desired separation because the generic gradient does not provide enough separation for the target compound needing purification.

    Read More

    How does acid concentration impact reversed-phase flash chromatography?

    August 24, 2022 at 2:55 AM / by Bob Bickler

    0 Comments

    Reversed-phase flash chromatography is extremely useful when purifying all types of compounds. Compounds that are charged or ionizable, however, typically need either a pH modifier (acid or base) or a buffer to better control compound retention, peak shape, and selectivity.

    Read More

    How important is flow rate in flash chromatography?

    August 9, 2022 at 1:54 PM / by Bob Bickler

    0 Comments

    I often get questions from customers about the influence of flow rate on their flash chromatography. Typically, the questions are…

    Read More

    Which solvents are best for terpene flash chromatography?

    July 6, 2022 at 2:59 PM / by Bob Bickler

    0 Comments

    Well, it’s spring as I write this, my favorite time of year, and the foliage is in various stages of bloom. I like the rebirth of nature and the floral aromas that emanate from the blooms. These botanical aromas are the result of the various terpenes and terpenoids in the plant which can be very different between species.

    Read More

    How to maximize UV detection sensitivity in flash chromatography

    June 21, 2022 at 4:11 PM / by Bob Bickler

    0 Comments

    Automated flash chromatography has become an integral component of the workflows of both synthetic organic chemistry and natural product research. The most utilized chromatographic technique is normal-phase, which uses a polar stationary phase filled column (i.e. silica) and a mix of non-polar and moderately polar solvents, i.e. hexane or heptane and ethyl acetate (EtOAc), resp.

    Read More

    How to isolate impurities from a reaction product

    June 7, 2022 at 5:57 PM / by Bob Bickler

    0 Comments

    Ensuring that the product of a reaction is pure is critical to that compound’s viability as a marketable entity. Impurities often require characterization if they are in excess of regulated limits. The isolation of these compounds can be quite challenging. 

    Read More

    How to avoid sample blowback when liquid loading

    May 24, 2022 at 2:19 PM / by Bob Bickler

    0 Comments

    Ever experience the problem where you load your dissolved sample into a flash column via a syringe only to encounter either resistance or “blowback”? Blowback is a term describing the situation where your sample does not stay in the column but flows back out of the column’s cap after the loading syringe is removed.

    Read More

    When do I need to use an ELSD with flash chromatography?

    May 11, 2022 at 2:16 PM / by Bob Bickler

    0 Comments

    Flash chromatography can be complex. Solvent choice, column size, stationary phase, loading technique, gradient method, flow rate, and detection parameters are all variables which factor into flash chromatography and your success with this purification technique. Of these variables, detection parameters, i.e. the type of detector, can really impact your flash chromatography results.

    Read More

    Is reversed-phase flash chromatography less expensive than normal-phase?

    April 26, 2022 at 2:41 PM / by Bob Bickler

    0 Comments

    For many labs on a tight budget, keeping expenses at a minimum is crucial. Many of these same labs are also required to become more sustainable, or greener, by reducing the amount of organic solvent they use. Reducing solvent also reduces expenses, but what is the impact on lab productivity?

    Read More

    What is the maximum flash column sample load volume?

    April 12, 2022 at 9:40 PM / by Bob Bickler

    0 Comments

    A fairly common question I receive is "how much of my reaction mixture can I load on my flash chromatography column?". To this question there is not a cut and dry answer because of a number of variables which influence the outcome. To help illustrate this, I will show in this post the results of a study I performed in my lab with one of my reaction mixtures.

    Read More

    When is Gradient Elution Better than Isocratic Elution?

    March 30, 2022 at 2:00 PM / by Bob Bickler

    0 Comments

    Gradient or isocratic elution, that is the question. Within flash chromatography these are the options afforded to separate reaction mixtures and natural product extracts and is the focus of this post.

    Read More