Instrumentation
Chromatographic separation was performed on an ACQUITYTM Ultra Performance Liquid Chromatography system (Waters, Mil-ford, MA, USA), consisting of a binary solvent delivery system andan autosampler. MS/MS detection was performed on a Xevo®TQ tandem quadrupole mass spectrometer (Waters, USA) equipped with an electrospray ionization (ESI) source. Data were acquired and processed with MassLynx V4.1 software.