Study on Thermostability and Photo-Isomerization of trans-Resveratrol by High Performance Liquid Chromatography and Liquid Chromatography-Electrospray Ionization-Mass Spectrometry
反式白藜芦醇热稳定性与光致异构化的高效液相色谱和液相色谱-电喷雾离子化质谱研究

The thermostability and photo-isomerization reaction mechanism of trans-resveratrol were studied by using high performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization-mass spectrometry ( LC-ESI-MS). A reversed-phase Hypersil-ODS column was used with the mobile phase consisting of 60/40 methanol-water, with addition of 0.05% trifluoroacetic acid for HPLC, and 0.1% formic acid and 5 mmol/L ammonium formate for LC-ESI-MS, at a flow rate of 0.5 mL/min. Diode array detection was set at 300 nm and the injection volume was 20 or 10 microL. Mass spectrometric conditions were in the negative mode. The results of thermostability test under 4, 20 and 40 degrees C indicated that the concentration of trans-resveratrol, after storage for 600 h, was decreased slightly under 4 degrees C, decreased by 5% under 20 degrees C, and 10% under 40 degrees C. In addition, the photo-isomerization reaction of trans- and cis-resveratrol under 254 nm and 365 nm UV irradiation was investigated by LC-ESI-MS, showing that the isomerization is based on p-status, and that some secondary reactions are radical induced.