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Direct Analysis of Underivatized Amino Acids

Relying on the high-efficiency chromatographic detection platform, BOC Sciences provides professional direct analysis services for non-derivatized amino acids, which can detect dozens of amino acids, such as glutamic acid, aspartic acid, etc. We have an independent analysis laboratory to provide professional test reports to ensure that the data is true and reliable. According to the specific needs of different customers, we can provide customized testing.

Why Establish Amino Acid Analysis Methods?

Amino acids are the basis of peptides and proteins, and are an indispensable class of small molecular substances in life activities. The analysis and research of amino acids in organisms is helpful to understand the life process and plays an important role in the diagnosis of diseases and the research of drugs.

Amino Acid Analysis Difficulties and Common Practices

Although there are various amino acid analysis methods, improving the existing methods to have better specificity and sensitivity has always been a hot and difficult issue in research. On the one hand, since amino acids contain two functional groups, amino and carboxyl, the overall polarity of amino acid molecules is very high, and it is difficult to obtain good retention directly on reversed-phase C18 chromatographic columns. On the other hand, most amino acids have poor UV absorption, and it is difficult to obtain highly sensitive responses on conventional UV detectors. In order to improve the analysis of amino acids, amino acids are usually processed by derivatization. The derivatization process is complex and requires high environmental conditions and amino acid structure. For the analysis of biological samples, derivatization processing will further complicate the complex system and increase the difficulty of later data processing.

Our Derivatized Amino Acid Analysis Services

Amino acids can be analyzed non-derivatized in different separation modes without the addition of ion-pairing reagents.

  • Reversed-phase chromatography mode

For some amino acids with relatively good hydrophobicity, such as L-hydroxyproline, L-proline, glycine and alanine, we directly use reversed-phase C18 column for analysis.

  • Hydrophilic-interaction chromatography (HILIC) mode

We can get good results in the retention and separation of amino acids in HILIC mode. The HILIC method has the advantages of simple pretreatment process, rapid detection, high resolution and high sensitivity. We can analyze a wide range of free amino acids from acidic to basic. When phosphates are used as the mobile phase, amino acids can be analyzed at the cutoff wavelength and with UV as the detector.

  • Ion exchange mode

Since amino acids are amphoteric compounds, they can be positively or negatively charged by adjusting the pH. We perform retention testing of amino acids in ion exchange mode.

    • Cation exchange mode

Under the cation exchange mechanism, amino acids that cannot be retained in the reverse phase mechanism (such as glycine, alanine, serine, threonine, lysine, glutamic acid) can be retained. However, basic amino acids cannot be eluted. Therefore, we usually use a dual mode combining reversed-phase and cation exchange mechanisms to separate and analyze amino acids.

Dual Mechanism Model Analysis

Dual Mechanism Model Analysis

    • Anion exchange mode

We can use anion exchange resin as stationary phase, alkaline solution as eluent, and directly analyze and determine amino acid by integral pulse amperometry.

In addition, we can add volatile ion-pairing reagents to the mobile phase system, and amino acids can be directly analyzed without derivatization, which meets the high-throughput analysis of clinical blood samples.

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