Flavor Authenticity Studies by ²H/¹H Ratio Determination Using On-line Gas Chromatography Pyrolysis Isotope Ratio Mass Spectrometry

Based on (2)H/(1)H ratio measurements of commercial synthetic and "natural" references, the recently developed on-line gas chromatography pyrolysis isotope ratio mass spectrometry (HRGC-P-IRMS) technique was used to determine the delta(2)H(SMOW) values of the flavor compounds decanal, linalool, and linalyl acetate, as well as those of E-2-hexenal and E-2-hexenol in foods and essential oils. In preceding model studies, the influence of sample preparation steps (simultaneous distillation extraction, SDE; solvent extraction, SE; liquid liquid extraction, LLE) on the delta(2)H values was found to be negligible. For decanal, the typical (2)H abundance, with higher content of (2)H for synthetic material (delta(2)H(SMOW) from -90 to -156 per thousand) and lower (2)H content for natural references (delta(2)H(SMOW) from -138 to -262 per thousand) was observed. Although the delta(2)H data recorded for linalool did not allow one to distinguish between synthetic (delta(2)H(SMOW) from -207 to -301 per thousand) and natural (delta(2)H(SMOW) from -234 to -333 per thousand) materials, the situation was somewhat more encouraging for linalyl acetate; delta(2)H(SMOW) values from -199 to -239 per thousand and from -213 to -333 per thousand were found for synthetic and natural samples, respectively. E-2-Hexenal and E-2-hexenol showed clear-cut origin-dependent differences in their (2)H/(1)H ratios; that is, delta(2)H(SMOW) values from -14 to -109 per thousand and from -263 to -415 per thousand as well as from -41 to -131 per thousand and from -238 to -348 per thousand were recorded for products from synthetic and natural origins, respectively.