Botanical and geographical origin identification of industrial ethanol by stable isotope analyses of C, H, and O

Abstract

The isotope ratios of carbon, hydrogen, and oxygen of rectified alcohols were determined to distinguish their botanical and geographical origins by continuous flow-isotope ratio mass spectrometry (CF-IRMS). The 13C/ 12C and 18O/16O ratios of 27 fermented alcohols with known origins showed clusters derived from each botanical origin, viz. corn, sugarcane, wheat, and tapioca. C3 and C4 plants were easily distinguishable by the 13C/12C ratio. Sugarcane and corn are both C4 plants, and they showed small differences in isotope ratios. The combination plots of the D/H and 18O/16O ratios enabled us to designate the geographical origins of alcohol derived from the same kind of crop, such as Chinese or American corn. The chemically synthetic and fermented alcohols were clearly distinguished by D/H and 18O/16O ratios. Isotope ratios were useful for origin identification of alcohol. We plan to construct a database of alcohol isotope ratios to determine the origins of raw materials in alcohol.