Measurement of chiral complexes of cyclodextrins and amino acids by electrospray ionization time-of-flight mass spectrometry

✍ Scribed by Ying Cheng; David M. Hercules

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 168 KB
• Volume: 36
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.175

✦ Synopsis

Measurement of chiral complexes of cyclodextrins and amino acids by electrospray ionization time-of-flight mass spectrometry

Chiral recognition of guest enantiomers by a chiral host is a challenging and important problem for analytical chemists. Methods which have been used to determine chiral recognition by host-guest complexation include NMR spectrometry, 1 x-ray diffraction, 2 induced circular dichroism, 3 and high-performance liquid chromatography (HPLC). 10 Mass spectrometry (MS) has also been used for studies of chiral compounds, although not extensively. Several research groups have reported using fast atom bombardment (FAB) MS 4,5 and liquid secondary ion mass spectrometry (LSIMS) 6 to determine the enantiomer excess of chiral amino acids and their derivatives via host-guest complexation by using chiral crown ethers and carbohydrates as host molecules. Electrospray ionization (ESI) MS was used by Garcia et al. 8 to examine the chiral recognition properties of spiroacetal polyethers. Lebrilla and co-workers 11 -13 also reported using an ESI-MS method for the determination of the enantiomeric excess in chiral amino acid mixtures, through gas-phase guest exchange reactions. Gas-phase ammonium-cyclodextrin compounds were studied by Kellersberger et al. 14 using a Fourier transform ion cyclotron resonance mass spectrometer equipped with an ESI source.

Here we report the use of ESI-MS to detect the solutionphase chiral recognition of the chiral amino acids tyrosine (Tyr) and tryptophan (Trp) by using ˛-and ˇ-cyclodextrins (˛-and ˇ-CD) as hosts. CDs (˛-, ˇ-, -) and their derivatives have been