The peptide mixture was dissolved in water containing 0.1% formic acid (FA) and analyzed using a U3000-nano online system coupled with an Orbitrap Q-Exactive HFX mass spectrometer (Thermo Fisher Scientific, Massachusetts, USA).Data acquisition was performed in data-dependent mode. The MS scan range was set to an m/z of 350–1500 with an accumulation time of 0.25 s. The top 20 most intense ions in MS1 were selected for MS/MS analysis, with a dynamic exclusion time of 20 s.