title: Relative quantification of enantiomers of chiral amines by high-throughput LC-ESI-MS/MS using isotopic variants of light and heavy L-pyroglutamic acids as the derivatization reagents.
abstract: L-Pyroglutamic acid (L-PGA) was evaluated as a chiral labeling reagent for the enantioseparation of chiral amines in terms of separation efficiency by reversed-phase chromatography and detection sensitivity by ESI-MS/MS. Several amines and amino acid methyl esters were used as typical representatives of the chiral amines. Both enantiomers of the chiral amines were easily labeled with L-PGAS at room temperature for 60 min in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 1-hydroxy-1H-benzotriazole as the activation reagents. The resulting diastereomers were completely separated by reversed-phase chromatography using the small particle (1.7 μm) ODS column (Rs=1.6-6.8). A highly sensitive detection at a low-fmol level (1-4 fmol) was also obtained from the multiple reaction monitoring (MRM) chromatograms. Therefore, a high-throughput determination was achieved by the present UPLC-ESI-MS/MS method. An isotope labeling strategy using light and heavy L-PGAs for the differential analysis of chiral amines in different sample groups was also proposed in this paper. As a model study, the differential analysis of the R and S ratio of 1-phenylethylamine (PEA) was performed according to the proposed procedure using light and heavy reagents, i.e., L-PGA and L-PGA-d5. The R/S ratio of PEA, spiked at the different concentrations in rat plasma, was almost similar to the theoretical values. Consequently, the proposed strategy using light and heavy chiral labeling reagents seems to be applicable for the differential analysis of chiral amine enantiomers in different sample groups, such as healthy persons and disease patients.
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Mochizuki
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Taniguchi
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Haruhito
authors.initials: H
authors.lastname: Tsutsui
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Jun Zhe
authors.initials: JZ
authors.lastname: Min
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Todoroki
authors.affiliation: Laboratory of Analytical and Bio-Analytical Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. Electronic address: toyooka@u-shizuoka-ken.ac.jp.
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Toyo'oka
mesh_terms: D000588:Amines / Q000032:analysis* / Q000097:blood; D000818:Animals; D002234:Carbodiimides / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium / Q000737:chemistry; D007553:Isotope Labeling; D008297:Male; D010627:Phenethylamines / Q000737:chemistry; D011761:Pyrrolidonecarboxylic Acid / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D013696:Temperature; D014230:Triazoles / Q000737:chemistry
chemical_list: D000588:Amines; D002234:Carbodiimides; D010627:Phenethylamines; D014230:Triazoles; C011852:1-hydroxybenzotriazole; D003903:Deuterium; D011761:Pyrrolidonecarboxylic Acid