Authenticity assessment of estragole and methyl eugenol by on-line gas chromatography-isotope ratio mass spectrometry

On-line capillary gas chromatography-isotope ratio mass spectrometry was used in the combustion (HRGC-C-IRMS) and the pyrolysis (HRGC-P-IRMS) modes to determine delta(13)C(PDB), delta(2)H(SMOW), and delta(18)O(SMOW) data of estragole (1) and methyl eugenol (2) originating from various sources. For 1, similar delta(13)C values, i.e., ranging from -35.4 to -29.9parts per thousand. and from -36.4 to -28.8parts per thousand. for the product of synthetic and natural origins, respectively, were found. The delta(2)H values ranged from -155 to -3parts per thousand. for synthetic 1 and from -193 to -105parts per thousand. for 1 from natural origin, whereas the determination of 6180 data gave values from +1.8 to +24.8parts per thousand . and from +2.7 to +18.7parts per thousand for 1 from synthetic and natural origins, respectively. As synthetic 2 is produced by methylation of natural eugenol, the IRMS techniques did not allow differentiation of synthetic 2 from the product of natural origin. The recorded data ranges were nearly identical, i.e., delta(13)C = -37.4 to -35.0parts per thousand and -41.1 to -32.2parts per thousand; delta(2)H = -155 to -126parts per thousand. and -217 to -107 parts per thousand; delta(18)O = +5.5 to +6.6parts per thousand and +2.7 to +6.9parts per thousand, each for 2 from synthetic and natural origins, respectively.