Tips & Tricks for Amino Acid Analysis – Part IV

Document created by anne_blackwell Employee on Jun 21, 2019Last modified by priya.jayaraman on Nov 8, 2019
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Ever wonder why chemical supplies are shipped or prepared a certain way?  Stability is often the answer.

Hi guys! We have a guest writer for today’s post, my colleague Bill from the small molecule columns team. He’s sharing some insight into why the extended amino acid standards from the AdvanceBio Amino Acid Analysis Kit are shipped separately and how to best prepare them. There’s even some electron pushing for anybody who secretly loves organic chemistry.

What is the proper sample preparation for the extended amino acids standards?

It has been noted that the procedures for preparation of Extended Amino Acid Standards have not been consistent. This application note describes making this solution just using de-ionized water. Another application note refers to making this solution using 0.01 N HCl and water. It does state however, “Solutions containing extended standards are unstable at room temperature. Keep them frozen and discard at first signs of reduced intensity.”

Some of the supplemental amino acid standards degrade in HCl, especially glutamine and asparagine. The correct answer is to dissolve the supplemental amino acids in de-ionized water, and if using them in a mixture with other amino acids, be aware that they are dissolved in dilute HCl, so they must be used quickly.

In addition, other amino acids are also noted to degrade under acid hydrolysis conditions. These include tryptophan and 4-hydroxyproline. However, the mechanism of their degradation is different.

Note the amide group on both amino acids. When exposed to acid, these groups would hydrolyze, releasing ammonia.

Mechanism illustration source

That wraps up our series on amino acid analysis. We’ll spend the next few posts on peptide mapping. Talk soon!

– Anne

Keywords: Bio columns, liquid chromatography, tips and tricks, amino acids, sample preparation, AdvanceBio blog

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