Ion pairing agents are used in a variety of strategies to improve overall purification efficiency. In a previous post, I utilized ion pairing agents to increase the peptide’s hydrophobicity, improving retention by the stationary phase and enabling purification. But what other strategies can be improved by using ion pairing agents?
In this post, I’ll utilize ion pairing agents to enable rapid peptide purification by flash chromatography. The use of ion pairing agents can in fact alter the peptide’s apparent hydrophobicity sufficiently that the desired peptide and it’s closely eluting impurities can be resolved. The question is, which one to choose?
Continue reading How to choose an ion pairing agent to improve your peptide purification
Recently there has been substantial motivation to consider and evaluate alternative, more environmentally friendly solvents. Some countries have even gone so far as to ban some of the more toxic, yet commonly used solvents. In addition to general toxicity, additional consideration in the green chemistry movement is the volume of solvent used in any particular application. In this regard, purification solvent selection is closely monitored as they are often used in large quantities.
One alternative that is growing in popularity is the use of methanol in place of acetonitrile for reversed phase purification of small molecules. Methanol is certainly less expensive, but is also a more environmentally-friendly solvent for use in purification applications. But it’s use for peptide purification has not been widely adopted to date. In today’s post, I’ll compare the purification efficiency of methanol when compared to acetonitrile for peptide purification by reversed phase flash chromatography.
Continue reading How does methanol as a mobile phase solvent impact peptide purification by reversed-phase flash chromatography?
In a previous post, I evaluated how flow rate can impact my purification efficiency using flash chromatography. I noticed though, at high flow rates a significantly later elution time for my peptide. I hypothesized that the increased pressure was driving the compound further into the pores, increasing the overall interaction with the stationary phase and causing the increased retention. We know that the particle size and particle pore size impact resolution and purification efficiency, so how does flow rate play a role with a different stationary phase?
In today’s post I’ll evaluate several flow rates using a reversed phase stationary phase material with slightly larger diameter particles that possess significantly smaller pores. The smaller pores should limit the access of the peptides to the stationary phase and negatively impact the purification.
Continue reading How does flow rate affect my peptide purification efficiency when using a small pore stationary phase?
Wow! I can’t believe it’s been a year since this whole blogging adventure started. This started as a technical resource for me and my colleagues within the peptide synthesis and purification space. The idea was to enable easy access to some of the hard-to-find answers for common questions that I have encountered working with different peptide groups.
The blog has grown steadily this year and for that I thank you. In the following post, I’ll highlight a few of the most popular posts from the past year as well a few of my favorites. I hope you will consider providing feedback using the survey link so that we can continue to grow, keeping the content interesting and relevant.
Continue reading Celebrating one year of the peptide synthesis and purification blog!
I’ve recently worked with several peptide groups that are trying out flash purification with their peptides for the first time. And it never fails, every single interaction includes the question “what flow rate should I use for these cartridges?”
There is a lot of information available highlighting optimal flow rates for HPLC method development, but very little information for larger particle stationary phases. I personally have used a wide range of flow rates for my peptide purification with differing outcomes. So in today’s post I’d like to have a more thorough discussion about mobile phase flow rate and it’s impact on your chromatography.
Continue reading What mobile phase flow rate should I use for my peptide purification with flash chromatography?