DIRECT-INJECTION GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC ASSAY FOR TRANS-RESVERATROL

We have developed a novel method to measure the concentration of the t rihydroxystilbene trans-resveratrol suitable for the analysis of wine and other biological materials. Solid-phase extraction is carried out on a reversed-phase disposable C-18 cartridge with elution of trans-re sveratrol by ethyl acetate. From the first 1 mL of the eluate collecte d, 1 mu L is injected directly into a gas chromatograph/mass spectrome ter coupled through a DB-5 column. The molecular ion at a mass of 228 was quantitated by selective ion monitoring using as standard trans-re sveratrol synthesized by a Wittig reaction. The method was linear up t o 10 mg/L with a detection limit of 0.05 mg/L, which can be increased 10-fold if required. Recovery of added synthetic trans-resveratrol in wine ranged from 83 to 111% with a mean of 100%. Within-run precision was 5-7%. The method is faster and simpler than those previously publi shed, which use organic-phase extraction, and yields higher values in wine presumably as a consequence of minimal loss during the solid-phas e extraction. The trans-resveratrol. concentration of wine is stable w hen protected from light for at least 6 weeks at 4 degrees C and for a t least 1 week at room temperature.