Alanine

Hydroxyproline seems to be the most promising amino acid used in carbon dating when isolated from bone collagen. Separation of amino acids is challenging, especially without the use of ions or inorganic buffers that can interfere with Mass spectrometer (MS) or contaminate the sample with modern carbon. Amino acids are also not retained in reverse-phase chromatography. The ideal solution would be using water only to separate the amino acids. This would allow a direct coupling to MS. We were able to separate hydroxyproline from proline and other simple amino acids like glycine and alanine in HPLC on Newcrom AH column using water only as a mobile phase. Using water also allowed UV detection at 205 nm which can’t be done if using a buffer based on acetic or formic acid.
See more information on radiocarbon dating here.
The same method can be modified to get symmetrical peaks and higher efficiency if a mobile phase with ionic modifier such as formic acid is used.

High Performance Liquid Chromatography (HPLC) Method for Analysis of Non-Essential Amino Acids on Primesep 100 by SIELC Technologies

High Performance Liquid Chromatography (HPLC) Method for Analyses of Non-Essential Amino Acids

Amino acids are the building blocks of proteins. Based on their dietary requirement, they are classified into essential and non-essential amino acids. Essential amino acids cannot be synthesized by the human body in sufficient quantities and must be obtained from the diet. Non-essential amino acids, on the other hand, can be synthesized by the body and are not dependent on dietary intake.

It’s worth noting that while these amino acids are considered “non-essential” for adults under normal circumstances because the body can synthesize them, there are situations where some may become “conditionally essential.” This means that under certain conditions like illness, stress, or trauma, the body might not produce them in sufficient quantities, and dietary intake becomes necessary. Arginine, for instance, is considered conditionally essential, especially during periods of rapid growth, illness, or trauma.

Amino acids can be retained, separeted and analyzed on a Primesep 100 mixed-mode stationary phase column using an isocratic analytical method with a simple mobile phase of water, Acetonitrile (MeCN), and a phosphoric acid (H3PO4) as a buffer. This analysis method can be detected in the UV regime at 200 nm.

Application Notes: Amino acids are polar ionic compounds which are not retained on reversed-phase column without ion-pairing reagent. In our application, lysine and arginine can be separated from other amino acids. Amino acids with a pH between 3 and 5 and with one basic and one acidic group become very polar. Therefore these amino acids don’t have strong ion-exchange interaction with Primesep C stationary phase. Amino acids with two amino groups still carry positive net charge and can interact with stationary phase by cations-exchange mechanism. pH variation of the mobile phase can be an effective tool to adjust selectivity of separation for zwitter-ionic, basic and acidic compounds. This method can be used for separation of mono-charged compounds from compounds having an extra charge.

Application Columns: Primesep C
Application compounds: Aspartic acid, Glutamic acid, Aspargine, Glycine, Proline, Alanine, Phenylalanine, Tyrosine, Leucine, Lysine, Arginine
Detection technique: UV, LC/MS, ELSD/CAD

11 underivatized amino acids (aspartic acid, glutamic acid, alanine, valine, methionine, isoleucine, cysteine, phenylalanine, histidine, lysine, and arginine) are separated by a Primesep 100 HPLC column by reversed-phase and ion-exchange mechanisms with LC/MS compatible conditions without the use of ion-pair reagents. The HPLC separation uses a TFA (trifluoroacetic acid) gradient in a mobile phase of water acetonitrile (MeCN, ACN with evaporative light scattering detection (ELSD).

Adding on to the previous HPLC separation of amino acids using Bufferless Ion Separation (BLIS) Chromatography; here we have additional amino acids separated on Primesep 200 column using only water and acetonitrile (MeCN, ACN) in the mobile phase.  Primesep 200 is a reverse-phase (RP) column with weak acidic ion-pairing groups embedded. With no buffer present in the mobile phase, detection can be achieved with UV, mass spectrometry (MS), evaporative light scattering detection (ELSD).