Welcome to the Biotage Peptide Synthesis Blogs.

      How to purify hydrophilic peptides - Why won't my peptide stick to my column?

      Jul 27, 2020 7:58:04 PM / by Elizabeth Denton posted in Chromatography Fundamentals, Peptides, Reversed-phase, Loading Techniques

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      Conversations are routinely held regarding handling hydrophobic peptides, but hydrophilic peptides offer their own challenges when it comes to purification.  In a previous post, I synthesized Octa-Arg, an extremely hydrophilic peptide. I used  ion pairing reagents to increase the peptide’s overall retention by the stationary phase, but choosing the solvent should to use for solubilizing the peptide for purification by flash column chromatography was no easy task.

      In today’s post, I’ll investigate several solvents commonly used to inject peptide samples for purification and evaluate their impact in peptide retention by the stationary phase.

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      Can I use a guard column for peptide purification with reversed-phase flash column chromatography?

      Jul 13, 2020 2:55:39 PM / by Elizabeth Denton posted in Chromatography Fundamentals, Peptides, Loading Techniques

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      More often than not and as a peptide chemist, I am asking myself in which solvent should I dissolve my peptide prior to purification by flash chromatography.  I have rarely considered an alternative to the standard liquid injection.  However, dry loading is a common technique used by organic chemists prior to their normal-phase purification efforts, especially if the compound isn’t particularly soluble in the mobile phase solvents.  To the best of my knowledge, dry loading is not commonly used for peptide purifications.

      Immediately, questions come to mind as I attempt this new loading technique.  Will my peak shape change if load additional material?  Does the stationary phase need to be equilibrated before use?  What solvent should I use to load my crude sample? How will my sample recovery be affected?  I will address a few of these questions in today’s discussion.

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      Does loading method influence my peptide recovery after purification?

      Jul 17, 2019 6:25:29 PM / by Elizabeth Denton posted in Chromatography Fundamentals, Peptides, Reversed-phase, Solvents, Workflow, Sfär, Loading Techniques, V-10, Isolera

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      In peptide purification, sample loading onto the column is rarely considered.  Most, if not all, HPLC instruments come equipped with a sample injection loop which demands a liquid injection of the sample for purification.  If you decide to use flash chromatography to purify your peptides though, liquid injection is no longer the exclusive method for sample introduction to the column.  Alternatively, dry loading crude material is a strategy often used in small molecule purification, particularly when sample solubility concerns arise.

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      How To Load The First Amino Acid Onto Wang Resin

      Apr 29, 2019 6:05:23 PM / by Elizabeth Denton posted in Peptides, Synthesis, Media and Resin, Loading Techniques

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      While resins loaded with the natural 20 amino acids are commercially available these days, there may be times when loading the first amino acid onto the resin in house may be necessary.  And unlike loading the first amino acid onto amide-leaving resins, the first coupling reaction for C-terminal acids can be chemically more challenging.

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