Continuous flow isotope ratio mass spectrometry for the measurement of nanomole amounts of 13CO2 by a reverse isotope dilution method

✍ Scribed by J. Guitton; F. Grand; L. Magat; M. Désage; A. Francina

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 129 KB
• Volume: 37
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.266

✦ Synopsis

Abstract

A simple method for the determination of nanomole amounts of ^13^CO~2~ generated from an in vitro reaction is reported. The incubation medium contains a known amount of unlabeled sodium bicarbonate and the gaseous ^13^CO~2~ enriches the atmosphere upon which a measurement of the isotopic enrichment (^13^CO~2~/^12^CO~2~) is made corresponding to a reverse isotope dilution. The quantification of the ^13^CO~2~ was performed by gas chromatography/isotope ratio mass spectrometry. This assay was validated in terms of linearity, accuracy and precision using three different substrates which produce ^13^CO~2~ either by enzymatic reaction [^13^C]urea, sodium [^13^C]formate) or by chemical reaction (sodium [^13^C]bicarbonate). Four calibration curves were tested for each ^13^C‐labeled substrate, allowing the quantification of ^13^CO~2~ from 25 pmol to 150 nmol. The dynamics of the assay were obtained as a function of the quantity of unlabeled sodium bicarbonate added to each sample. Copyright © 2001 John Wiley & Sons, Ltd.