Isotope ratio mass spectrometry coupled to liquid and gas chromatography for wine ethanol characterization.
Two new procedures for wine ethanol 13C/12C isotope ratio determination, using high-performance liquid chromatography and gas chromatography isotope ratio mass spectrometry (HPLC/IRMS and GC/IRMS), have been developed to improve isotopic methods dedicated to the study of wine authenticity. Parameters influencing separation of ethanol from wine matrix such as column, temperature, mobile phase, flow rates and injection mode were investigated. Twenty-three wine samples from various origins were analyzed for validation of the procedures. The analytical precision was better than 0.15 per thousand, and no significant isotopic fractionation was observed employing both separative techniques coupled to IRMS. No significant differences and a very strong correlation (r = 0.99) were observed between the 13C/12C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The potential advantages of the developed methods over the traditional one are speed (reducing time required from hours to minutes) and simplicity. In addition, these are the first isotopic methods that allow 13C/12C determination directly from a liquid sample with no previous ethanol isolation, overcoming technical difficulties associated with sample treatment.
Cabañero
Ana I
AI
Laboratorio Arbitral Agroalimentario, Ministerio de Medioambiente y Medio Rural y Marino, Ctra. Coruña Km 10,700, 28023 Madrid, Spain. acabanero@mapya.es
Recio
Jose L
JL
Rupérez
Mercedes
M