Chiral high-performance liquid chromatography analysis of alpha-amino acid mixtures using a novel SH reagent--N-R-mandelyl-L-cysteine and traditional enantiomeric thiols for precolumn derivatization.
Several chiral thiols, i.e. traditionally used enantiomerically pure SH reagents and novel N-R-mandelyl-L-cysteine (R-NMC) containing additional chiral center, have been applied as co-reagents in precolumn derivatization with o-phthalaldehyde for enantiomeric HPLC analysis of individual alpha-amino acids and their mixtures. The R-NMC-derived isoindoles as well as adducts with other thiols have a characteristic absorption maximum at 340 nm, and are highly fluorescent allowing detection of 10 microg/l of an amino acid. Investigated 19 amino acids were analyzed separately and in a mixture by a gradient HPLC after precolumn derivatization. The chromatographic behavior of formed isoindoles substantially differs for each of the thiols used for modification. In contrast to traditional enantiomeric thiols application of diastereomeric R-NMC provides higher resolution for alpha-amino acid enantiomers, with L,D-elution order (except for Arg). Combined use of R-NMC and other thiol enlarges the possibilities of this method, allowing accurate chiral analysis of complex amino acid mixtures.
Chernobrovkin
M G
MG
Department of Chemistry, Lomonosov Moscow State University, Vorob'ev Hills, 119992 Moscow, Russia.
Shapovalova
E N
EN
Guranda
D T
DT
Kudryavtsev
P A
PA
Svedas
V K
VK
Shpigun
O A
OA
D000111:Acetylcysteine / Q000737:chemistry; D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry; D007211:Indoles / Q000032:analysis; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013439:Sulfhydryl Reagents / Q000737:chemistry*; D009764:o-Phthalaldehyde / Q000737:chemistry
D000596:Amino Acids; D007211:Indoles; C506933:N-(R)-mandelyl-(S)-cysteine; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D009764:o-Phthalaldehyde; D003545:Cysteine; D000111:Acetylcysteine