title: Liquid chromatographic determination of D- and L-amino acids by derivatization with o-phthaldialdehyde and N-isobutyryl-L-cysteine. Applications with reference to the analysis of peptidic antibiotics, toxins, drugs and pharmaceutically used amino acids.
abstract: In order to evaluate and extend the applicability of an analytical method that enables the quantitative and simultaneous high-performance liquid chromatographic determination of D- and L-amino acids (DL-AAs) by automated precolumn derivatization with o-phthaldialdehyde together with the chiral thiol N-isobutyryl-L-cysteine [J. Chromatogr., 666 (1994) 259] selected natural and synthetic bioactive peptides, as well as pharmaceutically used formulations of AA, were investigated and the amounts of D- and L-AA determined by fluorescence detection. Peptides containing cys(e)ine were oxidized with performic acid prior to hydrolysis with 6 M HCl, and those containing Trp were hydrolyzed with 4 M methanesulfonic acid (24 h at 110 degrees C in both cases). Peptides analyzed were the peptide antibiotics bacitracin, gramicidins A and S, polymyxin B, metanicin C, the peptide toxin malformin A and the peptide drugs D-Arg-[Hyp3,Thi5,8,D-Phe7]-bradykinin, beta-casomorphin and alpha s1-exorphin. Further, the enantiomeric ratios of pharmaceutically used AA formulations containing racemic DL-Ser, DL-Asp and DL-Met were determined, and the AA drugs L-Asp and L-Trp were tested negatively for the presence of the respective D-enantiomers. In two aqueous formulations of L-AA used for parenteral nutrition, low amounts of D-AA (0.1-0.9% with respect to certain L-AA enantiomers and of totally 128 mg and 149 mg D-AAs per liter infusion solution) were determined.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000737:chemistry; D004345:Drug Industry; D008969:Molecular Sequence Data; D010455:Peptides; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013237:Stereoisomerism; D014118:Toxins, Biological / Q000737:chemistry*; D009764:o-Phthalaldehyde / Q000032:analysis* / Q000737:chemistry
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D010455:Peptides; D004364:Pharmaceutical Preparations; D014118:Toxins, Biological; C096972:N-isobutyrylcysteine; D009764:o-Phthalaldehyde; D003545:Cysteine