OPTIMIZATION OF A HS-SPME/GC-MS METHOD FOR DETERMINATION OF VOLATILE COMPOUNDS IN SOME CUBAN UNIFLORAL HONEYS

A headspace (HS)/solid phase microextraction (SPME)/gas chromatography-mass spectrometry (GC-MS) method was developed to determine the profiles of volatile compounds from three Cuban unifloral honeys: Turbina corymbosa (L.) Raf., Ipomoea triloba L. and Gouania polygama (Jacq.) Urb. The optimization of the extraction conditions was carried out by response surface methodology. The analytical conditions of the optimized HS-SPME method were: 65 mu m PDMS/DVB fiber, 6 g honey, 3 mL water and 20% w/w sodium chloride, 20 min for pre-extraction, 30 min for extraction at 60C and 4 min for GC desorption. The GC-MS analysis allowed the identification of 181 volatile compounds in these honeys. Possible markers for the floral classification of honeys were for the T. corymbosa type: 4-methyl methoxysalicylate, trans-pinocarveol, chavicol, methyl anisate, trans-alpha-bergamotene and alpha-bisabolol. In I. triloba honey, 2,5,5-trimethyl-3-tetrahydrofuranone and 1,2-diphenylethanol were found, while4-methyl-1-pentanol and isopentyl acetate were only present in G. polygama honey. With the use of the HS-SPME method in combination with multivariate analysis techniques such as Principal Component Analysis and K-nearest neighbor, it was possible to discriminate the different honeys according to their floral origin. PRACTICAL APPLICATIONS Honey is a natural product produced by Apis mellifera bees from nectar and secretions of the living parts of the plants. According to the nectar source, honeys can be multifloral (nectars from diverse flowers) or unifloral (nectar from only one flower). The floral origin of honey is an important characteristic in the evaluation of its quality. Control and characterization of the volatile compounds of unifloral honeys is highly important in Cuban apiculture, and has not been carried out so far. The objective of this work was to develop and optimize a method to determine origin of some Cuban unifloral honeys, by means of a headspace-solid phase microextraction.