HPLC analysis of tonka bean extracts.

Based on the results of GC-MS analysis, an HPLC procedure was developed for the determination of coumarin, dihydrocoumarin, melilotic acid (o-dihydrocoumaric acid), methyl melilotate, ethyl melilotate, 5-hydroxymethylfurfural and o-coumaric acid which are characteristic compounds of tonka beans. The presence of melilotic acid and ethyl melilotate in tonka beans has not been reported previously. Following HPLC analysis of tonka bean extracts produced in the laboratory and one sample of commercially available tonka bean absolute, evidence was provided that solvents used for production are decisive for the kind and amount of the compounds detected.