Hasegawa Hiroshi, Shinohara Yoshihiko, Akahane Kenji, Hashimoto Takao
Department of Pathophysiology, School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
J Chromatogr B Analyt Technol Biomed Life Sci. 2005 Sep 5;823(2):203-8. doi: 10.1016/j.jchromb.2005.06.010.
A method for the stereoselective determination of D- and L-enantiomers of both methionine and [(2)H3]methionine in rat plasma was developed using gas chromatography-mass spectrometry with selected-ion monitoring (GC-MS-SIM). DL-[(2)H7]Methionine was used as analytical internal standard to account for losses associated with the extraction, derivatization and chromatography. The amino acids were purified by cation-exchange chromatography using BondElut SCX cartridge and derivatized with HCl in methanol to form methyl ester followed by subsequent N-acylation with optically active (+)-alpha-methoxy-alpha-trifluoromethylphenylacetyl chloride to form diastereomeric amide. Quantification was performed by SIM of the molecular-related ions of the diastereomers on the chemical ionization mode. Endogenous L-methionine concentrations in 50 microl of rat plasma were measured with relative intra- and inter-day precision of 4.0 and 6.3%, respectively. The intra- and inter-day reproducibility in the amounts of D- and L-[(2)H3]methionine determined were in good agreement with actual amount added.
采用气相色谱 - 质谱联用选择离子监测（GC-MS-SIM）技术，建立了一种立体选择性测定大鼠血浆中甲硫氨酸和[(2)H3]甲硫氨酸的D型和L型对映体的方法。DL-[(2)H7]甲硫氨酸用作分析内标，以补偿与萃取、衍生化和色谱分析相关的损失。氨基酸通过使用BondElut SCX柱进行阳离子交换色谱纯化，并用甲醇中的HCl衍生化形成甲酯，随后用旋光性(+)-α-甲氧基-α-三氟甲基苯乙酰氯进行N-酰化反应，形成非对映体酰胺。通过在化学电离模式下对非对映体的分子相关离子进行选择离子监测来进行定量分析。测定50微升大鼠血浆中内源性L-甲硫氨酸的浓度，其日内和日间相对精密度分别为4.0%和6.3%。所测定的D型和L型[(2)H3]甲硫氨酸量的日内和日间重现性与实际添加量高度一致。
