Ten milliliter of wine were mixed in a centrifuge tube with 5mL of extraction solvent and the tube was agitated for30min in an orbital shaker.After centrifugation,3mL of the upper organic layer were transferred to a pear shape vial and carefully vaporated to dryness with rotary evaporator
at 40°C. The residue was re-dissolved in 1mL of cyclohexane for chromatographic injection.