13 C-stable isotope measurements of the sugar fractions of honey - a new method to detect adulteration?

13 C/ 12 C isotope ratio mass spectrometry is the established method to detect adulterations of honey with foreign sugars. δ 13 C values of honey and protein are compared. Admixtures of C4 sugars can be determined reliably while C3 sugars can only be detected in high amounts. Using liquid chromatography previously, isotope ratios of single sugar fractions (glucose, fructose, di- and trisaccharides) can be determined as well. Different δ 13 C values among each other should provide further indications of adulterations. But measurements of honeys, also in various stages of ripeness, show large natural differences between sugar fractions. Therefore judgements due to isotope differences are only possible in exceptional cases.