Characterization of Grape Cane Stilbenoids and Their Photo‐Degradation Products by HPLC‐DAD Coupled With Trapped Ion Mobility Spectrometry and High‐Resolution Tandem Mass Spectrometry

ABSTRACT Rationale Bioactive ( E )‐stilbenoids in vine extracts are prone to light‐induced transformation into the respective ( Z )‐isomers and further degradation products, often resulting in a loss of bioactivity. We sought to study stilbenoid degradation beyond that of the well‐researched resveratrol due to the high diversity of stilbenoids in nature. Methods Nine authentic, individual stilbenoids and a stilbenoid‐rich grape cane extract were irradiated with artificial sunlight and their photodegradation products analyzed by liquid chromatography coupled with diode array detection, electrospray ionization, trapped ion mobility spectrometry, and quadrupole time‐of‐flight high‐resolution tandem mass spectrometry (HPLC‐DAD‐ESI‐TIMS‐QTOF‐HR‐MS/MS). Results Overall, a total of 45 different transformation products were identified in light‐exposed standard solutions and the grape cane extract. For the first time, collision cross section values of grape cane stilbenoids (154.8–286.4 Å 2 ) and their degradation products (116.5–289.3 Å 2 ) are reported. TIMS allowed the separation of isomeric and isobaric photodegradation products that would be challenging to differentiate when not resolved by chromatography and sharing similar HR‐MS/MS fragmentation patterns, e.g., certain trihydroxyphenanthrenediones. Conclusion These results highlight the potential of combining liquid chromatography, TIMS, and HR‐MS/MS for these types of compounds to broaden the knowledge on photodegradation pathways of grapevine stilbenoids beyond resveratrol.