Targeted LC-MS Metabolite Analysis

Thermo Finnigan (Thermo Electron Corporation, Austin, TX, USA) LC system coupled with the mass spectrometer (LCQ-Duo ion trap) having an ESI source (ThermoQuest) was used. A Discovery HS F5 column (15 cm × 4.6 mm ID, 5 µm particles, Sigma-Aldrich Co, Steinheim, Germany) was used. The mobile phases were water and acetonitrile (ACN) (0.1% formic acid each). At 0 min, ACN was 5%, then increased to 30% over 60 min. The instrument was controlled by Xcalibur software (Xcalibur^TM 2.0.7, Thermo Scientific, Waltham, MA, USA). The MS was operated in negative mode, and ions were detected within 50–2000 m/z mass range in a full scan mode as before [10 (link)].