Xevo qtof hybrid quadrupole time of flight mass spectrometer

Ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry using a Waters Acquity UPLC chromatograph (Waters, Milford, MA, USA) equipped with a XEVO QTOF hybrid quadrupole time-of-flight mass spectrometer (Waters, USA) was used for sample profiling. The analysis was performed in negative ion mode in the m/z range of 550–1,500. The injection volume was 5 µL. The ionization source parameters were as follows: ionization source temperature was 150°C, desolvation temperature was 600°C, capillary voltage was 3 kV, sample injection cone voltage was 40 V, and nitrogen (desolvation gas) flow rate was 1,000 L h^–1. Chromatographic separation conditions were as follows: Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 μm, Waters, USA) was used with column temperature 40°C, and mobile phase flow rate was 0.4 mL min^–1. A 0.1% (v/v) solution of formic acid in water (solvent A) and a 0.1% (v/v) solution of formic acid in acetonitrile (solvent B) were used as the mobile phase. Chromatographic separation was performed using a gradient elution mode. The composition of the mobile phase changed according to the following program (B, % by volume): 0–2 min, 20%; 2–20 min, 20%; 20–20.10 min, 20%; 20.10–25.00 min, 20%–37%; 25.00–26.00 min, 37%–46%; and 26.00–26.10 min, 46%–95%.

The analysis was performed using a Waters Acquity UPLC system (Waters, Milford, MA, USA) equipped with a Xevo QTof hybrid quadrupole time-of-flight mass spectrometer (Waters, Milford, MA, USA). A sample (1 μL) was injected in an ACQUITY UPLC BEH Phenyl column (50 × 2.1 mm, 1.7 μm; Waters, Drinagh, County Wexford, Ireland). The column temperature was 40 °C, and the flow rate of the mobile phase was 0.4 mL/min. A 0.1% (by volume) solution of formic acid in water (solvent A) and a 0.1% (by volume) solution of formic acid in acetonitrile (solvent B) were used as the mobile phase.
Chromatographic separation was performed in the gradient elution mode. The gradient elution was performed by the following program (B, % by volume): 0–1 min, 35%; 1–7 min, 35 → 45%; 7–17 min, 45%; 17–17.5 min, 45 → 95%; 17.5–19 min, 95%; 19–19.5 min, 95 → 35%.
The analysis was carried out in the positive-ion mode in the m/z range of 100–1200. Ionization source parameters were as follows: ionization source temperature 120 °C; desolvation temperature 250 °C; capillary voltage 3.0 kV; sample injection cone voltage 30 V; nitrogen (desolvation gas) flow rate 600 L/h.
Commercial standard samples of baccatin III, cephalomannine, paclitaxel (Sigma-Aldrich, St. Louis, MO, USA), 10-deacetyl-7-xylosyl taxol, and taxusin (ChromaDex, Irvine, CA, USA) were used to identify 13-OH taxoids.