Online determination of H-2/H-1 and C-13/C-12 isotope ratios of cinnamaldehyde from different sources using gas chromatography isotope ratio mass spectrometry

摘要

The combination of gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) and gas chromatography-pyrolysis-isotope ratio mass spectrometry (GC-P-IRMS) is applied to the authenticity assessment of cinnamaldehyde from various sources. For that reason, cinnamon oils were self-prepared by steam distillation from three different varieties of cinnamon bark on the market, C. ceylanicum (ceylon), C. cassia (cassia) and C. burmanii (cassia vera). Furthermore, the so-called wood cinnamon was investigated, which is produced from the outer bark of older branches of cinnamon of minor quality. Self-prepared oils were analysed from commercial cinnamon powder. In addition several commercial samples of cinnamon oil and cinnamaldehyde, some of them declared to be natural, were investigated. delta(2)H(V-SMOW) and delta(13)C(V-PDB) values of cinnamaldehyde were determined and characteristic authenticity ranges were deduced, allowing the differentiation between synthetic and natural samples. By correlation of both the delta(2)H(V-SMOW) and delta(13)C(V-PDB) values, characteristic authenticity ranges were defined for ceylon, cassia and wood cinnamon. The delta(2)H(V-SMOW) and delta(13)C(V-PDB) values of cassia vera samples are in the range of cassia. By comparing the delta(2)H(V-SMOW) values of different self-prepared samples (ground bark, distillate) of cinnamon determined by TC/EA-IRMS with the corresponding GC-IRMS values, online GC-IRMS methods are proved to be essential in the authentication of complex natural products.