Gemini c18 110a analytical column

The analyses were performed using a Thermo Scientific LCQ FLEET system consisting of an LCQ FLEET ion trap mass spectrometer, a Surveyor MS Pump/Autosampler/PDA Detector (Thermo Fisher Scientific, Waltham, MA, USA) through an ESI source. The separation was obtained by using a Gemini® C18 110 A analytical column (150 × 2.00 mm i.d., 5 μm) and the pre-column (Phenomenex, Torrance, CA, USA). The mobile phase consisted of aqueous formic acid at 0.1% and acetonitrile (solvent B) at 0.3 mL/min (the injection volume was 10 µL). A linear solvent gradient was used as follows: from 10% B to 95% B in 25 min with a final plateau of 3 min at 100% B. The ion trap operated in data-dependent, full scan (60–2000 m/z), and MSⁿ mode to obtain fragment ions m/z with a collision energy of 35% and an isolation width of 3 m/z. The negative and positive parameters of the ion mode ESI source have been optimized to an ionization voltage of 5.0 kV, a capillary temperature of 320 °C, a capillary voltage of 32 V, a sheath gas flow rate of 25 arbitrary units (AU), and an auxiliary gas flow rate of 10 AU. Data was acquired using Thermo Excalibur 2.2 software (Thermo Fisher Scientific, MA, USA).