Van guard beh c18 column

The UPLC–MS
measurement for SCU was reported by Li et al.^{31 (link)} An Acuity UPLC system equipped with a binary pump, degasser, autosampler,
and temperature-controlled column compartment and a TQD quantum triple-quadrupole
mass spectrometer equipped with an electrospray ionization (ESI) source
(Waters Corp., Manchester, UK) were used for SCU analysis in the pharmacokinetics
and tissue distribution studies. Liquid chromatography (LC) was performed
by a Waters Van Guard BEH C18 column (2.1 mm × 50 mm, 1.7 μm)
at 45 °C with the mobile phase consisting of 0.1% formic acid
in acetonitrile (A) and 0.1% formic acid water (B). The gradient program
is as follows: 0–0.5 min, 5% A and 95% B; 0.5–3 min,
5–95% A and 95–5% B; and 3–3.5 min, 95–5%
A and 5–95% B. The peaks were obtained at a flow rate of 0.3
mL/min with a sample injection volume of 1 μL. The electrospray
positive ionization (ESI⁺) was used for detection and analysis.
In the positive ion mode, the SCU parameters are as follows: capillary
voltage at 3 kV, cone voltage at 30 V, and collision energy at 20
eV; the puerarin parameters are as follows: capillary voltage at 3
kV, cone voltage at 40 V, and collision energy at 30 eV. SCU and puerarin
(internal standard) were quantified using the selected ion recording
mode (SIR) of their parent ions, 463 and 417, respectively.

Chromatographic analysis was performed on an ACQUITY I-Class UPLC and a XEVO TQD triple quadrupole mass spectrometer equipped with an electrospray ionization interface (Waters, Milford, MA). Chromatographic separation was performed on a Waters Van Guard BEH C₁₈ column (2.1 mm × 50 mm, 1.7 μm). The column temperature was maintained at 40°C. The autosampler temperature was set at 8°C. The mobile phase, consisting of eluents A (0.1% formic acid (FA) in water, v/v) and B (0.1% FA in methanol, v/v), was delivered at a flow of 0.4 mL/min using a linear gradient program as follows: 2%–35% from 0 to 0.4 minutes and 35%–98% from 0.4 to 2.0 minutes. Posttime was set at 1.0 min for the mobile phase to revert to the initial 2% B before the next injection.
Mass analysis was designed as follows: capillary voltage, 3.0 kV; source temperature, 150°C; desolvation temperature, 500°C; cone gas flow, 50 L/h; and desolvation gas flow, 800 L/h; solvent removal and cone hole reverse blowing gas was nitrogen; collision gas was argon; scanning mode was multireaction monitoring; the main parameters are shown in Table 1. Data processing was performed using MassLynx 4.0 Software (Waters, Milford, MA).