Selective control of the radical-scavenging activity of poly(phenols) in aqueous media in terms of their electron-donor properties, using a stable organic radical as chemical sensor

► 3K+ TSPTM3− has been prepared as a stable and water-soluble radical. ► Electron transfer reaction between (poly)phenols and 3K+ TSPTM3− has been confirmed. ► The activity of (poly)phenols against 3K+ TSPTM3− has been demonstrated to be higher at pH 8 than at pH 7. ► Catecholic and pyrogallolic moieties of (poly)phenols are discriminated by 3K+ TSPTM3−.