Direct liquid chromatography tandem mass spectrometry analysis of amino acids in human plasma
•Amino acid analysis in plasma is of utmost importance in human medicine•Actual methods of amino acid analysis are very time consuming or not specific or not robust•HPLC-MS/MS using a mixed-mode stationary phase avoids pre column derivatization of amino acids•HPLC-MS/MS using a mixed-mode stationary...
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Published in: | Journal of Chromatography A Vol. 1622; p. 461135 |
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Main Authors: | , , , , , , , |
Format: | Journal Article |
Language: | English |
Published: |
Elsevier B.V
05-07-2020
Elsevier |
Subjects: | |
Online Access: | Get full text |
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Summary: | •Amino acid analysis in plasma is of utmost importance in human medicine•Actual methods of amino acid analysis are very time consuming or not specific or not robust•HPLC-MS/MS using a mixed-mode stationary phase avoids pre column derivatization of amino acids•HPLC-MS/MS using a mixed-mode stationary phase avoids ion pairing reagent adding to amino acids
Here we describe a new HPLC–MS/MS method using a mixed mode stationary phase and a binary gradient of elution for the rapid separation and quantification of AAs in human plasma without derivatization or ion pairing reagent addition. The sample preparation procedure consists in a single dilution step after protein precipitation with sulfosalicylic acid. The proposed method allows for the unambiguous identification and analysis of 52 AAs and related compounds including the separation of isomers and isobars in an 18 min chromatographic run including the conditioning and the equilibration times. AAs were detected by selective reaction monitoring. Internal calibration was used for the quantification of 37 AAs, including 25 using the corresponding isotopically labeled internal standards. External calibration (no internal standard) was used for five additional analytes. Qualitative detection was achieved for the remaining compounds.
Validation studies evaluated accuracy, linearity, within- and between-run precision, lower limits of detection and quantification for 37 amino acids present in commonly used quality control samples. For within-run precision CVs averaged 3.8 % (n = 30) for all compounds. For between-run precision, CVs averaged 8.6 % for all compounds (n = 20). Correlation with the common standard ion-exchange chromatography with post-column derivatization method was also performed for 32 plasma samples. While the proposed method is at least 50 times more sensitive, the data showed good correlation with slopes equal or higher than 0.9 and correlation coefficients mostly higher than 0.90. The method was successfully applied for analysis of plasma samples for detection of inherited disorders of amino acid metabolism. |
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ISSN: | 0021-9673 1873-3778 |
DOI: | 10.1016/j.chroma.2020.461135 |