Optimizing distillation techniques for isotopic determinations in beverages

Isotopic analysis offers insights into the authenticity, tracing origin, and detecting adulteration in beverages, with applications in various legal contexts. This research addresses challenges in the distillation process to identify the optimal method for preparing samples for isotopic determinations. This study aimed to compare three distillation systems: cryogenic, Cadiot column and steam for carbon, hydrogen and oxygen determinations in ethanol. Furthermore, to explore the benefits of cryogenic method in beverage distillation and to perform the method validation. Additionally, to evaluate the efficiency of the steam distillation for carbon isotopic determination. The ethanol obtained through cryogenic distillation exhibited δ13C ranging from -29.54 to -24.60‰, slightly lower than those observed in the Cadiot column (-29.12 to -24.64‰). Trueness analysis, however revealed comparable results for both methods, supported by satisfactory Z-score and relative error. The outcomes for hydrogen and oxygen exhibited considerable disparities with significant differences. The results of δ13C found by steam distillation and cryogenic were similar and the mean difference found between the systems was 0.05‰ and the relative error was 0.20%. The study further explored the advantages of cryogenic distillation in ethanol extraction, demonstrating its efficiency for carbon determinations with notable benefits in terms of time and volume required for extraction. Steam distillation proved feasible for carbon determinations, showing similar results to cryogenic distillation. These findings not only present options for laboratories but also highlight the efficiency of cryogenic distillation in ethanol extraction, offering practical applications for isotopic analysis.