Column was allowed to re-equilibrate during one additional minute before next injection, giving a total
run time of 7 min. Injection volume was of 10 mL. For MS/MS analysis nitrogen was employed as desolvation and
cone gas at a flow rate of 900 and 48 L h1, respectively. The ESI sourcewas operated in positive ion mode with a capillary voltage of 3.2 kV, and 120 C temperature for the source and 390 C for desolvation.The cone voltage was 40 V and gas argon was used in the collision cell at a flow rate of 0.14 mL min1 (1.3 e5 mbar) for ion fragmentation. MassLynx v4.1 software (Waters, Manchester, UK) was employed for instrumental operation, data acquisition and analysis.