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Analytical method for simultaneous determination of bulk and intramolecular 13 C‐isotope compositions of acetic acid
Author(s) -
Nimmanwudipong Tarin,
Gilbert Alexis,
Yamada Keita,
Yoshida Naohiro
Publication year - 2015
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.7398
Subject(s) - chemistry , acetic acid , intramolecular force , isotope , chromatography , analytical chemistry (journal) , radiochemistry , stereochemistry , organic chemistry , nuclear physics , physics
Rationale Headspace solid‐phase microextraction (HS‐SPME) combined with gas chromatography/pyrolysis‐gas chromatography/combustion‐isotope ratio mass spectrometry (GC/Py‐GC/C‐IRMS) was developed for the simultaneous determination of the intramolecular and molecular carbon‐isotopic composition (δ 13 C value) of acetic acid. Methods The δ 13 C values of carboxyl and methyl carbon were standardized using calibration curves constructed from the regression between the measured δ 13 C values and the δ 13 C values of working standards determined in a previous study. We applied this developed HS‐SPME‐GC/Py‐GC/C‐IRMS technique to commercial vinegars. Results In one injection analysis, the bulk and intramolecular δ 13 C values of pure acetic acid standards can be obtained. The repeatability (1σ) of the bulk δ 13 C values is within ±0.4‰, and that of the δ 13 C carboxyl and δ 13 C methyl values is within ±0.6‰. The intramolecular δ 13 C values of acetic acid in vinegars exhibit a similar pattern. The average Δδ value (δ 13 C COOH – δ 13 C CH3 ) is 4.3 ± 2.0‰. Conclusions The approach presented herein for the molecular and intramolecular δ 13 C determination of acetic acid avoids switching between configuration systems and thereby reduces systematic errors. It is expected to be useful for examining isotope fractionation associated with processes related to organic acid (bio)transformations. Copyright © 2015 John Wiley & Sons, Ltd.