Quantitative Chiral Analysis of Sugars by Electrospray Ionization Tandem Mass Spectrometry Using Modified Amino Acids as Chiral Reference Compounds

Abstract

Rapid quantitative enantiomeric analysis of mannose, glucose, galactose, and ribose is achieved using electrospray ionization and cluster ion dissociation with data analysis by the kinetic method. Several modified amino acids (N-Ac-L-Phe, N-benzoyl-L-Phe, N-t-Boc-L-Phe, N-Ac-L-Pro, N-t-Boc-L-Pro, N-Fmoc-L-Pro, N-Ac-L-Tyr, O-Me-L-Tyr) and four transition divalent metal cations (Co2+, Cu2+, Ni2+, and Zn2+) were tested to select the best system for chiral recognition and quantitation of each sugar. Quantitative determinations of the enantiomeric compositions of sugar solutions were achieved using either multiple- or two-point calibration curves; differences between the actual and experimental values were <2% enantiomeric excess (ee).

Quantitative determination of the enantiomeric composition of panthotenic acid solutions: a mass spectrometry experiment

“…Significantly, it was verified that the relative concentrations of pantothenic acid vs. N-Fmoc-L-Pro did not affect the chiral discrimination in these systems. 16,20 This is an indispensable result for successful quantitative analysis of unknown samples. …”

“…Therefore, the best systems to be selected are those ones that provide R chiral as far as possible from unity, provided that accurate abundance ratios can still be measured. It must be mentioned, however, that the selection of adequate systems for enantiomeric distinction has been exclusively performed, as recently reported in literature, 13,16,19 based on an alternative procedure, i.e. the mass-selection and fragmentation of the trimeric complexes …”

Stereoselectivity in the collision-activated reactions of gas phase salt complexes

“…These differences can be exploited (i.e., by comparison to data for known standards) and used to determine the enantiomeric purity of a sample. Cooks [3][4][5][6][7][8][9][10][11][12][13][14][15][16], Dearden , , Speranza [27][28][29][30][31][32][33][34][35], and others have provided useful examples of this approach to stereochemical analysis.Along with methods for analyzing the enantiomeric purity of products, there is a growing need for the development of new reaction processes that are stereoselective. In general, these processes have been probed in the condensed phase, but there is no reason why mass spectrometry could not also be used to screen gas phase reactions for stereoselectivity [35,36].…”

“…These differences can be exploited (i.e., by comparison to data for known standards) and used to determine the enantiomeric purity of a sample. Cooks [3][4][5][6][7][8][9][10][11][12][13][14][15][16], Dearden , Lebrilla [21][22][23][24][25][26], Speranza [27][28][29][30][31][32][33][34][35], and others have provided useful examples of this approach to stereochemical analysis.…”

Investigation of ion/molecule reactions as a quantification method for phosphorylated positional isomers: An FT-ICR approach

“…In terms of differentiating isomers of important biomolecules by mass spectrometry based techniques, several methods have been reported as classified and reviewed by Cooks and co-workers [16,17] and others [18 -28]. For example, chiral recognition based on gasphase ion/molecule reactions has been investigated by several research groups [18 -25].…”