ANYL 505 |
| We have recently demonstrated a method for the determination of the enantiomeric composition of various chiral analytes using electrospray ionization-mass spectrometry (ESI-MS). ESI-MS of solutions containing the analyte of interest and a quasi-racemic mixture of pseudo-enantiomeric chiral selectors affords selector-analyte complexes in the mass spectrum. The pseudo-enantiomeric chiral selectors are chosen such that each has a different mass and a higher affinity for the opposite analyte enantiomer as its pseudo-antipode. Observation of the relative peak heights of the mass-differentiated selector-analyte complexes in the ESI mass spectrum allows enantiomeric composition determinations as well as a determination of the extent of enantioselectivity. The observed MS-derived enantioselectivities correlate well with the enantioselectivities observed by chiral HPLC when analogs of the chiral selectors are tethered to the surface of silica. Additionally, this method is being used as the basis for the discovery of chiral selectors. One simply records the mass spectra on addition of each analyte enantiomer to a combinatorially-derived mixture of potential chiral selectors. Differences in the relative peak heights of selector-analyte complexes (normalized to appropriate achiral internal standards) are used as a metric for chiral selectivity. Investigations into the scope and limitations of this method, along with progress toward the discovery and evaluation of new chiral selectors will be presented. |
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General Papers
1:30 PM-4:50 PM, Thursday, 1 September 2005 Washington DC Convention Center -- 153, Oral
Division of Analytical Chemistry |