High-performance thin-layer chromatography evaluation of the counterfeiting of vanilla flavoring

Determining the origin of vanilla in flavoring agents is becoming a real problem nowadays, as more and more counterfeit products enter the market. New method for the analysis of vanillin from synthetic and natural sources as well as its homologues, ethyl vanillin and tonka, in vanilla-flavoring products is presented. In addition to standards of vanillin and ethyl vanillin, the following products that produced vanilla flavorings were analyzed: vanilla and tonka pods, two vanillin sugars, one vanilla sugar, and six vanilla essences. The separation was performed by high-performance thin-layer chromatography on silica gel F254 plates using the mixture of toluene–chloroform–acetone (7:8:2, V/V) as the mobile phase. The detection of compounds was performed under UV illumination at 254 nm and 366 nm. To confirm the presence of vanillin and ethyl vanillin in flavoring products, in situ UV spectra of the bands present at the appropriate hRF were recorded. The results show the ability of the method to monitor the composition of vanilla flavorings as well as the evaluation of counterfeiting of vanilla-flavoring products.