Authentication of Tonka beans extracts (Dipteryx odorata) using LC-UV/MS, GC-MS and multi element (13C, 2H and 18O) bulk specific isotope analysis

Abstract

Tonka bean extract, prepared from Tonka beans, is mainly composed of Coumarin. However, due to alternative industrial procedure of production, different solvents and mixtures of solvents were tested for extraction. Investigation using HPLC-DAD-MS indicates influence of extraction procedure on compositions of main constituents. New polyphenols structures have also been found in extracts and improve the chemical analysis knowledge of these products. Waxes compositions using fatty acids methyl esters gas chromatography analysis have been determined and indicate important amounts of behenic and lignoceric acids. High polar constituents (sugars) were also pointed out with trimethyl silanization. As synthetic Coumarin addition represents the main adulteration, isotopic values of Tonka coumarin, isolated by crystallization, have also been determined using an elemental analyzer connected to an isotope ratio mass spectrometer (EA-IRMS). The δ13C values of authentic coumarin range from − 32.88 to − 31.38‰ for δ13C, between − 113‰ and − 83‰ for δ2H, and between 23.0 and 28.0‰ for δ18O. No isotopic effect was observed with different solvents extraction procedures, indicating that IRMS investigation of Coumarin is a powerful tool applied for naturalness control.