Evaluation of the Hygroscopicity of Amino Acids Reference Materials by Thermogravimetric Analysis

Kato, Hisashi; Bao, Xinnu; Suzuki, Akiko; Ihara, Toshihide

doi:10.2116/bunsekikagaku.66.375

Cited by 6 publications

(4 citation statements)

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“…Although there are some existing products for amino acid standard solutions, those with sufficient accuracy have not been supplied evenly worldwide. The National Institute of Advanced Industrial Science and Technology (AIST/NMIJ) in Japan has developed high-purity certified reference materials for 17 proteinogenic amino acids [68,69] and a method for evaluating the purity of 22 types of non-protein amino acids and the related compounds, which are relevant for clinical chemistry, food chemistry, and pharmaceutical biotechnology [70,71]. In addition, it is necessary to determine the stability of each amino acid present in the mixed solutions in order to prepare metrologically traceable amino acid mixed standard solutions.…”

Section: Reference Intervals Of Plasma Amino Acid Concentration In Jamentioning

confidence: 99%

Development of Precolumn Derivatization–LC/MS for Amino-Acid-Focused Metabolomics

Miyano

Nakayama

2021

Chromatography

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Focused metabolomics facilitates the understanding of the current phenotype of living organisms, involves highly practical methods for investigation, and allows for the acquisition of highly quantitative data for important endogenous metabolites. The authors developed novel precolumn derivatization reagents for the analysis of amino acids, which are particularly important endogenous metabolites, through precolumn liquid chromatography/tandem mass spectrometry (LC/MS/MS). One of the reagents facilitated sub-femtomole-to-attomole-scale amino acid detection. We also developed an automated precolumn derivatization amino acid analyzer using another reagent for liquid chromatography/mass spectrometry (LC/MS). With this device, nearly 40 amino acids can be analyzed within a short time (<10 min), compared with the time (~2 h) taken by a conventional automated postcolumn derivatization amino acid analyzer. For highly accurate and precise analysis of free amino acid concentration in human plasma, we validated all steps, from blood collection to measurement, by using the proposed analyzer and developed a test procedure for studying free amino acid metabolomics in human plasma. While calculating the reference intervals of plasma amino acid concentrations in healthy individuals, it was found that the balance of amino acid concentrations in plasma is useful for risk screening of diseases including cancer, diabetes, and myocardial infarction. This functional-group-targeted analysis through LC/MS for amino acid was also effective for dipeptide, tripeptide, and D, L-amino acid analyses and amino acid detection in tissue by imaging mass spectrometry.

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Section: Reference Intervals Of Plasma Amino Acid Concentration In Jamentioning

confidence: 99%

Development of Precolumn Derivatization–LC/MS for Amino-Acid-Focused Metabolomics

Miyano

Nakayama

2021

Chromatography

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“…At the same time, reliability of the results is assured by cross-validation between two of the methods, qNMR, DSC and titrimetry, or by verification of qNMR or DSC results with GC or HPLC result. In addition, volatility (by sublimation) and hygroscopicity of the materials are tested by thermal gravimetry in a temperature and humidity chamber before purity assessment processes [48]. From the results, the suitable sample handling conditions for each material, temperature and humidity ranges are determined to avoid bias at weighing processes.…”

Section: Calibration Service Of Purity Assessmentmentioning

confidence: 99%

Conventional and new traceability schemes of organic standards for safe water supply in Japan

et al. 2019

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Metrological traceability to the International System of Units (SI) is required to ensure reliability of analytical results. For this purpose, SI-traceable standard solutions of respective analytes are essential for common analytical methods such as chromatography. However, it is not so easy to fulfill demands due to the existence of a vast number of targets, especially in the case of organic analysis. Because high-purity organic materials which are raw materials of standard solutions must be characterized by compound-independent methods, the mass balance approach (subtraction method) and the primary methods of measurement (e.g. the freezing point depression method and titrimetry) are used. Recently, quantitative NMR (qNMR) has been popularized.

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“…Secondly, several amino acids, such as Arg, Lys, and Pro, are hygroscopic, 16 which makes gravimetric preparation difficult. In our previous study, it was possible to handle almost all amino acids stably by maintaining relative humidity at less than 30% at 25 C. 17,18 Therefore, to prevent contamination and moisture adsorption, we weighed the amino acids using an analytical balance equipped with a commercially-available auto-dosing solution system 19 in a glove box, and maintained the relative humidity at less than 30% at 25 C. The auto-dosing solution system is capable of automatically and continually weighing amino acids, which will reduce the preparation time dramatically. Moreover, the use of a dedicated cartridge of the auto-dosing system will decrease the risk of contamination.…”

Section: Development Of a Contamination-free System For Preparing Amimentioning

confidence: 99%

Effects of the pH and Concentration on the Stability of Standard Solutions of Proteinogenic Amino Acid Mixtures

et al. 2017

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To prepare metrologically traceable amino acid mixed standard solutions, it is necessary to determine the stability of each amino acid present in the mixed solutions. In the present study, we prepared amino acid mixed solutions using certified reference standards of 17 proteinogenic amino acids, and examined the stability of each of these amino acids in 0.1 N HCl. We found that the concentration of glutamic acid decreased significantly during storage. LC/MS analysis indicated that the instability of glutamic acid was due to the partial degradation of glutamic acid to pyroglutamic acid in 0.1 N HCl. Using accelerated degradation tests, we investigated several solvent compositions to improve the stability of glutamic acid in amino acid mixed solution, and determined that the change of the pH by diluting the mixed solution improved the stability of glutamic acid.

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Evaluation of the Hygroscopicity of Amino Acids Reference Materials by Thermogravimetric Analysis

Cited by 6 publications

References 0 publications

Development of Precolumn Derivatization–LC/MS for Amino-Acid-Focused Metabolomics

Development of Precolumn Derivatization–LC/MS for Amino-Acid-Focused Metabolomics

Conventional and new traceability schemes of organic standards for safe water supply in Japan

Effects of the pH and Concentration on the Stability of Standard Solutions of Proteinogenic Amino Acid Mixtures

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