Quantification of bioactive phenols, like stilbenes and flavonols (SaF), has been conducted to evaluate the nutraceutical potential of red wines. However, there is still a lack of full validated, fast and accessible liquid chromatography methods offering high selectivity and a simple procedure. We present here the use of a high-resolution mass spectrometer to evaluate the selectivity of a feasible and traditional liquid chromatography technique (HPLC-DAD) to analyze markers of aglycone SaF in red wines. The SaF compounds were tested: trans-resveratrol, trans-eviniferin, quercetin, myricetin, and kaempferol, as well as trans-cinnamic acid, one of their precursors. System suitability and validation tests were employed for the selected conditions (octylsilane column, methanol mobile phase, and gradient elution). The validation process ensured the HPLC-DAD method was selective, linear, sensitive, precise, accurate and robust. The method was then applied to red wine samples from the Campanha Gaúcha region, Southern Brazil. The real samples contained different SaF levels, showing that the method is applicable to routine use. Furthermore, this was the first SaF characterization of red wines from the Campanha Gaúcha, contributing to regional and product development. Keywords Bioactive phenols Á Red wine Á Liquid chromatography Á Mass spectrometry Á Validation Abbreviations Symbols t R Retention time (min) V/V Volume/volume (%) R s Resolution TF Asymmetry k Capacity factor N Theoretical plates r 2 Coefficient of determination F calc Calculated Fisher value F tab Fisher table value n Number of repetitions p Probability m/z Mass/charge (Da)Greek letters k max Maximum ultraviolet absorption wavelength (nm)