Comparing the stable carbon isotope ratio of sugars and proteins is one way of checking for the adulteration of honey with C4 sugar syrups (e.g. corn syrup). Detecting C3 sugar syrups (e.g. from rice) is a lot more challenging and requires specialist and relatively expensive analytical equipment (e.g. 1H-NMR and/or LC-IRMS). A new method (purchase required) uses periodate oxidation of the sugars to produce formaldehyde, followed by reaction with ammonia to form hexamethylenetetramine (HMT). The hydrogen isotope ratio in HMT is measured by EA-IRMS, which is a much more “entry-level” isotopic analytical technique. The method was developed by the IAEA, mindful of the needs of low and middle income countries. The IAEA is developing a database, with its member States, to further correct for the natural variation in hydrogen isotope ratios, that has a geographical component also observed in techniques like SNIF-NMR.
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