One injection to profile the chemical composition and dual-antioxidation activities of Rosa chinensis Jacq

•An on-line system was used to detect the antioxidant activity of Rosa chinensis.•80 compounds were separated and identified.•DPPH and FRAP activities of active compounds were evaluated.•11 samples were analyzed and compared for their activities. An on-line high-performance liquid chromatography−diode-array-detector−electrospray ionization−ion-trap−time-of-flight−mass spectrometry−total antioxidant capacity detection (HPLC−DAD−ESI−IT−TOF−MS−TACD) system was applied for the identification and evaluation of antioxidants in Rosa chinensis Jacq., an edible flower in food industry and a widely used traditional Chinese medicine. With the help of this platform, the HPLC fingerprint, mass fragmentations, and sample activity profiles against 1,1-diphenylpicryl-2-hydrazyl radical (DPPH•) and ferric reducing antioxidant power (FRAP) were recorded after one injection. Using this technique, 80 compounds were separated and identified by their LC/MS behaviors with the assistance of standard compounds. In addition, 11 different Rosa chinensis Jacq. samples were profiled and then quantified for their DPPH• and FRAP activities. Interestingly, a total of 52 compounds showed antioxidative effects against DPPH• and 61 were active against FRAP. The results demonstrated that the on-line system is a powerful technique for antioxidant discovery in Rosa chinensis Jacq. and other food resources.