Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids

The urea cycle has been found to be closely associated with certain types of cancers and other diseases such as cardiovascular disease and chronic kidney disease. An analytical method for the precise quantification of urea cycle amino acids (arginine, ornithine, citrulline, and argininosuccinate) by...

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Main Authors: Yuko Sumida, Makoto Tsunoda
Format: Article
Language:English
Published: MDPI AG 2024-02-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/29/3/700
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author Yuko Sumida
Makoto Tsunoda
author_facet Yuko Sumida
Makoto Tsunoda
author_sort Yuko Sumida
collection DOAJ
description The urea cycle has been found to be closely associated with certain types of cancers and other diseases such as cardiovascular disease and chronic kidney disease. An analytical method for the precise quantification of urea cycle amino acids (arginine, ornithine, citrulline, and argininosuccinate) by off-line two-dimensional liquid chromatography (2D-LC) combined with fluorescence-based detection was developed. Before analysis, the amino acids were derivatised with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) to obtain NBD-amino acids. The first dimension involved the reversed-phase separation, in which NBD derivatives of urea cycle amino acids were completely separated from each other and mostly separated from the 18 NBD-proteinogenic amino acids. The samples were eluted with stepwise gradient using 0.02% trifluoroacetic acid in water–acetonitrile as the mobile phase. In the second dimension, an amino column was used for the separation of NBD-ornithine, -citrulline, and -argininosuccinate, while a sulfonic acid column was used to separate NBD-arginine. The developed 2D-LC system was used to analyse human plasma samples. The fractions of NBD-urea cycle amino acids obtained in the first dimension were collected manually and introduced into the second dimension. By choosing appropriate mobile phases for the second dimension, each NBD-urea cycle amino acid eluted in the first dimension was well separated from the other proteinogenic amino acids and interference from endogenous substance. This could not be achieved in the first dimension. The urea cycle amino acids in human plasma sample were quantified, and the method was well validated. The calibration curves for each NBD-urea cycle amino acid showed good linearity from 3 (ASA) or 15 (Orn, Cit, and Arg) to 600 nM, with correlation coefficients higher than 0.9969. The intraday and interday precisions were less than 7.9% and 15%, respectively. The 2D-LC system is expected to be useful for understanding the involvement of the urea cycle in disease progression.
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spelling doaj.art-b711523e5e1842dabd94f9d558f2a47c2024-02-09T15:19:08ZengMDPI AGMolecules1420-30492024-02-0129370010.3390/molecules29030700Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino AcidsYuko Sumida0Makoto Tsunoda1Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, JapanGraduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, JapanThe urea cycle has been found to be closely associated with certain types of cancers and other diseases such as cardiovascular disease and chronic kidney disease. An analytical method for the precise quantification of urea cycle amino acids (arginine, ornithine, citrulline, and argininosuccinate) by off-line two-dimensional liquid chromatography (2D-LC) combined with fluorescence-based detection was developed. Before analysis, the amino acids were derivatised with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) to obtain NBD-amino acids. The first dimension involved the reversed-phase separation, in which NBD derivatives of urea cycle amino acids were completely separated from each other and mostly separated from the 18 NBD-proteinogenic amino acids. The samples were eluted with stepwise gradient using 0.02% trifluoroacetic acid in water–acetonitrile as the mobile phase. In the second dimension, an amino column was used for the separation of NBD-ornithine, -citrulline, and -argininosuccinate, while a sulfonic acid column was used to separate NBD-arginine. The developed 2D-LC system was used to analyse human plasma samples. The fractions of NBD-urea cycle amino acids obtained in the first dimension were collected manually and introduced into the second dimension. By choosing appropriate mobile phases for the second dimension, each NBD-urea cycle amino acid eluted in the first dimension was well separated from the other proteinogenic amino acids and interference from endogenous substance. This could not be achieved in the first dimension. The urea cycle amino acids in human plasma sample were quantified, and the method was well validated. The calibration curves for each NBD-urea cycle amino acid showed good linearity from 3 (ASA) or 15 (Orn, Cit, and Arg) to 600 nM, with correlation coefficients higher than 0.9969. The intraday and interday precisions were less than 7.9% and 15%, respectively. The 2D-LC system is expected to be useful for understanding the involvement of the urea cycle in disease progression.https://www.mdpi.com/1420-3049/29/3/700arginineornithinecitrullineargininosuccinatefluorescence
spellingShingle Yuko Sumida
Makoto Tsunoda
Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids
Molecules
arginine
ornithine
citrulline
argininosuccinate
fluorescence
title Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids
title_full Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids
title_fullStr Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids
title_full_unstemmed Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids
title_short Development of a Two-Dimensional Liquid Chromatographic Method for Analysis of Urea Cycle Amino Acids
title_sort development of a two dimensional liquid chromatographic method for analysis of urea cycle amino acids
topic arginine
ornithine
citrulline
argininosuccinate
fluorescence
url https://www.mdpi.com/1420-3049/29/3/700
work_keys_str_mv AT yukosumida developmentofatwodimensionalliquidchromatographicmethodforanalysisofureacycleaminoacids
AT makototsunoda developmentofatwodimensionalliquidchromatographicmethodforanalysisofureacycleaminoacids