Simultaneous determination of selenomethionine enantiomers in biological fluids by stable isotope dilution gas chromatography–mass spectrometry

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2011-11, Vol.879 (29), p.3253-3258
• Main Authors: Matsukawa, Takehisa, Hasegawa, Hiroshi, Shinohara, Yoshihiko, Kobayashi, Jun, Shinohara, Atsuko, Chiba, Momoko, Ichida, Kimiyoshi, Yokoyama, Kazuhito
• Format: Article
• Language: English
• Subjects: Animals; cation exchange chromatography; Chiral separation; derivatization; diastereomers; enantiomers; gas chromatography-mass spectrometry; Gas Chromatography-Mass Spectrometry - methods; GC–MS; hydrochloric acid; ionization; ions; isotope dilution technique; Least-Squares Analysis; methanol; Mice; monitoring; pharmacokinetics; Reproducibility of Results; Selenomethionine; Selenomethionine - blood; Selenomethionine - chemistry; Sensitivity and Specificity; Stable isotope; stable isotopes; Stereoisomerism
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2011.03.057

A method for the stereoselective determination of d- and l-enantiomers of selenomethionine in mouse plasma was developed using gas chromatography–mass spectrometry with selected-ion monitoring (GC–MS-SIM). dl-[ 2H 3, 82Se]selenomethionine was used as analytical internal standard to account for losses associated with the extraction, derivatization and chromatography. Selenomethionine enantiomers in mouse plasma 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 (+)-α-methoxy-α-trifluoromethylphenylacetyl chloride to form diastereomeric amide. Quantification was performed by SIM of the molecular-related ions of the diastereomers on the chemical ionization mode. The intra- and inter-day precision for d- and l-selenomethionine spiked to mouse plasma gave good reproducibility with relative standard deviation of 3% and 3% for d-selenomethionine and 6% and 3% for l-selenomethionine, respectively. The estimated amounts were in good agreement with the actual amounts spiked, the intra- and inter-day relative error being 5% and 2% for d-selenomethionine and 2% and 1% for l-selenomethionine, respectively. The present method is sensitive enough to determine pharmacokinetics of selenomethionine enantiomers.