Measurement of Carbon Isotope Ratio in Vanillin Using the CM-CRDS Method: Achieving an Expanded Uncertainty Below 0.1‰

Isotopic analysis is an effective method for quality control and detection of adulterated food products, with the elemental analyzer isotope ratio mass spectrometry (EA-IRMS) being the conventional approach, specified in relevant regulatory documents. Although measuring the carbon isotope ratio by combustion module cavity ring-down spectroscopy (CM-CRDS) has gained significant interest for isotope analysis of food products, its metrological characteristics remain understudied for analysis of the isotopic composition of vanillin. Therefore, this article focuses on the development of a measurement procedure of the carbon isotope ratio in vanillin in preparation for the international key comparison CCQM-K167 “Carbon Isotope Delta Measurements of Vanillin”. The experimental part of the research was carried out using the reference installation included in the State primary standard for units of molar fraction, mass fraction, and mass concentration of components in gases GET 154-2019. The expanded uncertainty (at k = 2) of this measurement method was < 0.09‰, which is comparable to the best measurements obtained by the EA-IRMS method. The achieved results validate the applicability of the CM-CRDS method for quality control and detection of adulterated vanillin.