Background. Stable carbon isotope analysis of sugars in honey by LC-isotope ratio mass spectrometry (IRMS) is a useful tool for detecting adulteration of honey with extraneous sugar. Purity criteria based on13C/12C ratios of saccharides in honey, determined by LC-IRMS of a large number of authentic honey samples, have been elaborated. However, no interlaboratory comparison (ILC) has yet been performed to estimate the precision of the method under reproducibility conditions. Objective. To address this knowledge gap an ILC involving 14 laboratories and using six honey samples was conducted. Methods. The participants were allowed to use their LC-IRMS-based method of choice for sample preparation and compound separation. Results. The precision figures were estimated according to ISO 5725:1994. The repeatability relative standard deviation (RSDr) for the determination of δ13C values of fructose and glucose varied between 0.3 and 0.5%, with 0.3 and 1.0% for disaccharides, and 0.7...

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