MeOH, 0.1% HCOOH, v/v) to reach 10% solution B over 0.5 min, followed by an increase to 60% solution B in 8 min and then to 90% in 1 min; these conditions were kept for 6 min before returning to the initial conditions. The column oven was set to 40 °C and UV monitoring was carried out at 215 and 254 nm. These chromatographic conditions were used in subsequent analyses.