2.8. LC-MS/MS Conditions
The LC-MS/MS system comprised liquid chromatography (Shimadzu, MD, USA) with a binary pump (LC-30AD), an autosampler (SIL-30AC), a controller (CBM-20A) and an ABSciex QTRAP 5500 mass spectrometer (SCIEX, Redwood City, CA, USA). The chromatograms were monitored using Analyst 1.7, and the data were analyzed using MultiQuant 3.0 software (SCIEX, Redwood City, CA, USA). The metabolites were separated using Synergi™ Fusion-RP column (2.5 µm, 100 × 2 mm) obtained from Phenomenex (Torrance, CA, USA). The mass spectrometer was operated in negative electron spray ionization (ESI) mode, and the detection was performed in multiple reaction monitoring (MRM) mode. The summary of MS conditions precursor ions (Q1), product ions (Q3), declustering potential (DP), collision energy (CE), and ESI ion modes used for analysis are listed in 