Simultaneous measurement of amino acid enantiomers in the serum of late-life depression patients using convenient LC–MS/MS method with Nα-(5-fluoro-2,4-dinitrophenyl)-l-leucinamide Derivatization

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 230; p. 115387
• Main Authors: Liu, Mingxia, He, Jing, Ruan, Canjun, Pan, Weigang, Mao, Peixian, Sun, Zuoli, Wang, Gang, Yang, Jian
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.06.2023
• Subjects: Amino acid enantiomers; Amino Acids - chemistry; Chromatography, High Pressure Liquid - methods; Chromatography, Liquid - methods; Depression; Dinitrobenzenes; Glycine; Humans; Late-life depression; LC-MS/MS; Nα-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide; Stereoisomerism; Tandem Mass Spectrometry - methods; LC-MS/MS; FDLA; Amino acid enantiomers; Late-life depression; NMDAR; FDAA; ODS; Nα-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide; N(α)-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/j.jpba.2023.115387

D-amino acids may be indicators of late-life depression but separation and quantification of enantiomers which differ only by optical rotation sign remain challenging due to their identical physical and chemical properties. A convenient LC-MS/MS method was developed for the simultaneous measurement of l- and d-amino acids based on the chiral derivatization reagent, Nα-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide, and conventional octadecylsilane reversed-phase column. Methanol was used as the extraction solvent and a single-step derivatization reaction using volatile triethylamine eliminated the requirement for desalination prior to LC-MS/MS. Simultaneous separation and identification of 21 amino acids and the enantiomeric compositions of the 18 chiral proteogenic entities were achieved. Low limits of detection (0.03–4.0 nM), wide linear range (0.01–20 μM), good precision (RSDs < 10 %) and negligible matrix effects indicated the suitability of the method. Application of the method to the quantification of serum chiral amino acids in late-life depression patients (n = 40) and controls (n = 35) found a total of 17 L-amino acids, 14 D-amino acids, DL-asparagine, glycine and γ-aminobutyric acid. The statistical evaluation showed significant differences of glycine, L-threonine and D-methionine between late-life depression patients and controls, indicating that these are potential biomarkers of late-life depression. [Display omitted] •A convenient LC-MS/MS method for multiple amino acid enantiomers was developed based on FDLA and ODS column.•The simplified pretreatment and derivatization steps were easy to implement.•This method revealed the profiles and differences of amino acid enantiomers in late-life depression patients and controls.