Chromatographic analysis was carried out on a C18 HyPurity (50 mm × 2.1 mm, 3 μm) column
(Thermo Scientific) thermostated at 40 °C. Mobile phase A was a 90:10 water:methanol mixture containing 5 mM of ammonium acetate and mobile phase B was a 10:90 water:methanol mixture containing 5 mM of ammonium acetate