Thesamples were dissolved in HPLC grade MeOH (0.4 mg/mL) and infused
directly to the ESI source using a syringe pump at a flow rate of 180μL/h.
The nebulizer and drying gas was nitrogen and set at 0.4 bar and 4.0 L/min,
respectively, with the drying gas temperature being 180C. Capillary voltage
was3.2kV.Massspectrawereacquired overtherange503500 Da. The
samples were processed using Bruker Data Analysis software.WatersHPLC
equipment (Millipore Corp., Waters Chromatography Division, Milford