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A Peer reviewed papaer of an interlaboratory comparison of a Liquid Chromatography-Isotope Ratio Mass Spectrometry (LC-IRMS) method for the determination of ¹³C/¹²C ratios of saccharides in honey has been published.

This paper is based on a European Comission Joint Research Centre report, which was previosly reported on the Food Authenticity Network: EC Publishes report on the Interlaboratory Comparison of LC-IRMS applied on honey - News - FoodAuthenticity

Stable carbon isotope analysis of sugars in honey by LC–IRMS is a useful tool for detecting adulteration of honey with extraneous sugar.

Syrups that mimic the composition of honey that are produced by chemical and/or enzymatic modification of starch or sucrose are difficult to detect (10). If the starting product is obtained from a C4 plant, such as maize or sugar cane, stable carbon isotope ratio analysis (SCIRA) using a combination of an elemental analyzer (EA) and an isotope ratio mass spectrometer (IRMS) offers a possibility to detect additions down to a level of 7% (11).

Sugars originating from C3 plants such as beet root or generated from rice or wheat starch escape detection by SCIRA. Combining LC with IRMS (LC–IRMS) offers new possibilities for detecting honey adulteration with sugars derived from C3 plants and increases the sensitivity for detecting C4 sugars (12, 13).

Addition of 1% C4 sugars and 10% C3 sugars can be reliably detected using the LC–IRMS approach. Another benefit is that, as the method determines the ¹³C/¹²C ratios of saccharides in honey, it moves away from reliance on external databases.

The method has gained popularity (14–20) but has never been subjected to multilaboratory validation, until now, which is a prerequisite for further developing it into a standard by a standards-developing organization. This peer reviewed publication reports on an interlaboratory comparison of this method. Read open access paper.

This method has now been accepted as a work item for standardisation by Working Group 6 (Stable Isotope Analysis) of CEN Technical Committee 460 (Food Authenticity).

The rise in volumes and prices of grapes and wine has encouraged fraud and adulteration in the oenological field. One of the most common forms of adulteration, is the addition of sugar to grape must using cane, beet sugar, or syrups coming from vegetable sources like cereals or fruits. The OIV (International Organisation of Vine and Wine) has issued specific official isotopic methods to determine sugar adulteration, but they are not always effective. In this study by Italian researchers, they compared the δ13C value of sugars extracted from grape must analysed by EA-IRMS (elemental analysis - IRMS) with the δ13C value of proline analysed by GC-c-IRMS, after extraction and derivatization. δ13C and δ15N of proline have also been used as potential geographical markers. Also, the δ13C values of two characteristic grapes must sugars (myo and scyllo – inositol) was measured by GC-c-IRMS after derivatization. The results indicated that the compound specific isotope analysis represents a novel analytical tool to support and improve certification and control procedures of wine making.

Read the abstract here