Determination of Intramolecular 13C Isotope Distribution of Pyruvate by Headspace Solid Phase Microextraction-Gas Chromatography-Pyrolysis-Gas Chromatography-Combustion- Isotope Ratio Mass Spectrometry (HS-SPMEGC- Py-GC-C-IRMS) Method

Abstract

This paper presents the improvement of analytical methods for intramolecular carbon isotope compositions (δ13C) of pyruvate. Decarboxylated by H2O2, pyruvate yields acetic acid and CO2. Headspace solid phase micro-extractiongas chromatography-pyrolysis-gas chromatography-combustion-isotope ratio mass spectrometry (HS-SPME-GCPy- GC-C-IRMS) was used to measure the intramolecular δ13C values of acetic acid. δ13C value of CO2 can be later calculated using mass balance equation. The method’s consistency was confirmed by comparison of the δ13C value of CO2 from calculation to its direct measurement. Results of this study confirmed the method improvement because pyruvate 13C intramolecular distribution patterns were obtained. Two intramolecular 13C distribution patterns for commercial chemical reagents were found using this developed method. Intramolecular 13C distribution patterns for pyruvate were found for application in dietary supplements. Its origin was inferred. The method presented herein is expected to be a useful tool for categorization of pyruvate into different intramolecular 13C distribution patterns, which might indicate different production processes or raw materials.