Determination of Resveratrol and Piceid Isomers in Bee Pollen by Liquid Chromatography Coupled to Electrospray Ionization-Mass Spectrometry

A new method has been developed to determine resveratrol and piceid isomers in bee pollen using liquid chromatography (LC) coupled to electrospray ionization-mass spectrometry (ESI-MS). An efficient extraction procedure has also been proposed (average analyte recoveries were between 89 and 96 %); this involved a cleaning step with hexane, a solid-liquid extraction using a mixture of ethanol and water (80:20, v/v), and a concentration step in a rotary evaporator. The separation of all the compounds was achieved using a C-18 column (150 x 4.6 mm) and a mobile phase composed of 1 % (v/v) formic acid in water and acetonitrile at a flow rate of 0.8 mL/min. The method was fully validated in terms of selectivity, limits of detection (LOD) and quantification (LOQ), linearity, precision, and accuracy. The LOD and LOQ values ranged from 10 to 25 and 35 to 80 mu g/kg, respectively. Finally, the proposed method was applied to analyze bee pollen samples from different origins.