Hp 1100 lc ms system

The analysis for the determination of the concentration of silybin and its glucuronides and sulfates was performed on an Agilent HP 1100 LC-MS system (Agilent, CA, United States) with Waters ACQUITY UPLC^® BEH C18 Column (1.7 μm, 2.1 × 50 mm, Waters Corp., Ireland) protected by a C18 Security Guard cartridge (4 × 2.0 mm i.d., Phenomenex, Torrance, CA, United States). Silybin A and B were well separated using optimized gradient elution with 0.1% formic acid in water (mobile phase A) and methanol (mobile phase B) at a flow rate of 0.4 ml/min within 10 min at room temperature (22°C). The gradient elution was performed as follows (time: mobile phase B percentage): 0 min: 25%, 6 min: 40%, 6.5 min: 25%.
Mass spectrometry parameters: capillary voltage, -4000 V; drying gas, 9 L/min; drying gas temperature, 325°C; nebulizer pressure, 40 psi; fragment voltage, 35 V; dwell time, 200 ms; scan mode, selective ion monitoring (SIM) with [M-H]^- for silybin (m/z 481), mono-glucuronide (m/z 657), and NG (m/z 271). The LC-MS data were collected by Agilent ChemStation Software.

The bioactive components of A. ringens ethanolic root extract were identified on a HP 1100 LC-MS system (Agilent Technologies, Santa Clara, CA) with a DAD-diode array detector and a quaternary pump, a Mass Selective Detector Ion Trap XCT mass spectrometer with an electrospray ionization interface (ESI). The injection volume of the extract was 0.5 μL, loaded onto a C-18 column. The elution medium of two solvent systems A and B (90% acetate–water and 10% methanol, respectively) was a constant mobile phase made up of 10% B for 5 min, 10–100% B over 20 min, 100% B for 6 min, and reequilibration of the column, possessing a flow rate of 200 μL/min. Spectra recordings were in the negative and positive ionization mode between m/z 50 and 1200. The bioactive compounds in the extract were identified through comparison of the fragment features with those on the National Institute Standard and Technology MS library (NIST-MS library).