Although it is a widely occuring substance (for ex:1,2) natural vanillin is produced on a commercial basis only fromvanilla planifolia, a tropical orchid. Vanillin is of great economic importance for La Réunion Island (Indian Ocean) which is one of the main producers of that substance. Vanillin is of interest not only in cookery but also in pure chemistry (it is used, for example, as a lignin model compound3, its reactivity has been studied4, and empirical spectrophotometric determination of vanillin concentration is currently used5,6, besides the development of selective electrodes7).