DISPERSIVE LIQUID LIQUID MICROEXTRACTION COUPLED TO HIGH PRESSURE LIQUID CHROMATOGRAPHY (HPLC) AND ULTRAVIOLET DIODE ARRAY DETECTION (UV-DAD) FOR THE ANALYSIS OF PHENOLIC COMPOUNDS IN HONEY

A novel approach for the rapid analysis of phenolic componds in homey samples based on dispersive liquid liquid microextraction (DLLME) is presented. Generally, the analysis of phenolic compounds in honey involves the elimination of matrix components, mainly sugars, and the preconcentration of analytes before the determination, which is carried out most often by HPLC coupled with differents detector [1, 2]. Liquid-liquid extraction (LLE) with organic solvents and solid phase extraction (SPE) are very often used to extract phenolic compounds from honey [1, 2]. SPE on Amberlite XAD-2 followed by LLE with diethyl ether [3] is the most popular technique applied, but the use of C18 sorbents in SPE clean-up has also been reported [4-5]. These methods are laborious time consuming and use large amounts of organic solvent. The availability of fast, and inexpensive analytical procedures for the determination of phenolic compounds in honey is highly demanded for the quality control, the nutraceutical research and the authentication and characterization of botanical origin. The aim of this research was developed a fast and inexpensive DLLME method suitable for determination of phenolic compounds in honey. Of the main phytochemicals reported in honey, seven phenolic acids (caffeic acid, ellagic acid, ferulic acid, p-coumaric acid, protocatechuic acid, syringic acid and vanillic acid) and ten flavonoids (apigenin, chrysin, galangin, hesperetin, kaempferol, luteolin, myricetin, pinobanksin, pinocembrin and quercetin) were selected as target analytes. The main parameters affecting on DLLME efficiency, such as extraction solvent and dispersant solvent, their volume, the matrix/water ratio, types and salt amount, water pH were carefully studied and optimised to achieve the best extraction efficiency. HPLC-UV was selected as detection method and HPLC-HRMS was used to characterize the compounds extracted by DLLME and to investigate the applicability of this extraction technique to other phytochemicals of honey. After the optimization, the developed analytical procedure was applied to the analysis of Calabrian honey samples of different botanical origin. Moreover the analytical performance of DLLME method were compared with the several methods most used in the analysis of phenolic compounds in honey. The proposed method, which is demonstrated to be quick, cheap, accurate and highly selective, was successfully applied to the analysis of tipical Italian honey