Simultaneous determination of melatonin and trans-resveratrol in wine by dispersive liquid-liquid microextraction followed by HPLC-FLD

Abstract

The discovery of melatonin (Mel) in wines triggered a new interest in the paradigm of health benefits and wine consumption, usually ascribed to trans-resveratrol (trans-RSV). In this context, a dispersive liquid-liquid microextraction for the analysis of Mel and trans-RSV in wines by LC-FLD was developed. A 2(6-1) factorial design was used to identify the significant variables (p < 0.05) and Central Composite Design was used to achieve the optimal conditions: 300 mu L of chloroform (extracting solvent), 1500 tL of acetonitrile (disperser solvent) and 1500 mg of NaCl (ionic strength). Excellent linearity (R-2 > 0.9999), repeatability (< 3.55%), and accuracy (< 7.18%) were obtained using a blank matrix and recoveries (> 91.9%) using wines. The method was successfully applied to the analyses of Mel (0.63-7.44 ng mL(-1)) and trans-RSV (169-2616 ng mL(-1)) in different wine varieties. Comparison with literature point the overall advantages of the new method.