Identification of isomers of resveratrol dimer and their analogues from wine grapes by HPLC/MSn and HPLC/DAD-UV

► Three compounds are tentatively as new compounds based on the fragmentation behaviours of HPLC/(+)ESI-MSn. ► The relative abundance of two key product ions are utilised for the key structure identification of a resveratrol dimer. ► Based on their HPLC/DAD-UV spectra, two compounds were tentatively identified as cis and trans-configuration, respectively.