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Validation of pentaacetylaldononitrile derivative for dual 2 H gas chromatography/mass spectrometry and 13 C gas chromatography/combustion/isotope ratio mass spectrometry analysis of glucose
Author(s) -
Sauvinet Valérie,
Gabert Laure,
Qin Du,
LouchePélissier Corinne,
Laville Martine,
Désage Michel
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4294
Subject(s) - chemistry , mass spectrometry , isotope ratio mass spectrometry , gas chromatography , chromatography , isotope dilution , gas chromatography–mass spectrometry , repeatability , isotope , analytical chemistry (journal) , physics , quantum mechanics
A reference method to accurately define kinetics in response to the ingestion of glucose in terms of total, exogenous and endogenous glucose is to use stable‐isotope‐labelled compounds such as 2 H and 13 C glucose followed by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis. The use of the usual pentaacetyl (5Ac) derivative generates difficulties in obtaining accurate and reproducible results due to the two chromatographic peaks for the syn and anti isomers, and to the isotopic effect occurring during acetylation. Therefore, the pentaacetylaldononitrile derivative (Aldo) was validated for both isotopes, and compared with the 5Ac derivative. A correction factor including carbon atom dilution (stoichiometric equation) and the kinetic isotopic effect (KIE) was determined. Analytical validation results for the 2 H GC/MS and 13 C GC/C/IRMS measurements produced acceptable results with both derivatives. When 2 H enrichments of plasma samples were ≤1 mol % excess (MPE), the repeatability (RSD Aldo Intra assay and Intra day <0.94%, RSD 5Ac Intra assay and Intra day <3.29%), accuracy (Aldo <3.4%, 5Ac <29.0%), and stability of the derivatized samples were significantly better when the Aldo derivatives of the plasma samples were used ( p < 0.05). When the glucose kinetics were assessed in nine human subjects, after glucose ingestion, the plasma glucose 2 H enrichments were identical with both derivatives, whereas the 13 C enrichments needed a correction factor to fit together. Due to KIE variation, this correction factor was not constant and had to be calculated for each batch of analyses, to obtain satisfactory results. Mean quantities of exogenous glucose exhibit marked difference (20.9 ± 1.3g (5Ac) vs. 26.7 ± 2.5g (Aldo)) when calculated with stoichiometric correction, but fit perfectly when calculated after application of the correction factor (22.1 ± 1.3g (5Ac) vs. 22.9 ± 1.9g (Aldo)). Finally, the pentaacetylaldononitrile derivative, used here in GC/C/IRMS for the first time, enables measurement of 2 H and 13 C enrichments in plasma glucose with a single sample preparation. Copyright © 2009 John Wiley & Sons, Ltd.