Characterization of Material Study
Goldenseal Characterization of Material Experiment
|Sample||Compound measured||Value||Measurement||Study sequence||Additional information||N replicates|
For product extraction, 200 mg of sample and 20 mL methanol were added to a 20 mL scintillation vial. Mixtures were shaken overnight at room temperature, filtered, and dried under reduced pressure and stored at -80°C until analysis.
Q ExactivePlus quadrupole-orbitrapmass spectrometer
Electrospray ionization (ESI)
Waters Acquity UPLC
95:5 (A:B) for 1 min, then gradient to 0:100 over 20 minutes, holding for 1 min at 0:100
Waters Acquity UPLC BEH C18 1.7 μm, 2.1 × 50 mm
Ultraperformance (UP) LC-MS data were acquired using a Q ExactivePlus quadrupole-orbitrapmass spectrometer with an electrospray ionization source coupled to an Acquity UPLC system. Each sample was resuspendedin methanol to yield a concentration of 1 mg/mL.Triplicate injections of 3 μLwere then performed. Samples were eluted from a Waters Acquity UPLC BEH C18 1.7 μm, 2.1 ×50 mm column at a flow rate of 0.3 mL/min using the following binary gradient with solvent A consisting of H2O (0.1% formic acid added) and solvent B consisting of CH3CN (0.1% formic acid added): initial isocratic composition of 95:5 (A:B) for 1.0 min, increasing linearly to 0:100 over 8 min, followed by an isocratic hold at 0:100 for 1 min, gradient returned to starting conditions of 95:5 for 2 min, and held isocratic again for 1 min. The mass spectrometer was operated in the positive/negative switching ionization mode over a full scan range of m/z 150-2000 with the following settings: capillary voltage, 5 V; capillary temperature, 300 °C; tube lens offset, 35 V; spray voltage, 3.80 kV; sheath gas flow 35 and auxiliary gas flow 20.
Quantification of the major alkaloid components of the goldenseal products used 15 calibration standards. LC-MS analysis was conducted as described. Standards were prepared in spectrometric-grade MeOHand diluted in a two-fold dilution series ranging from 0.1-200 μg/mL before injection. A calibration curve was constructed by plotting the area of the selected ion chromatogram for each standard versus nominal concentration. Concentrations of each standard in the extracts were determined by 1/x2 weighted least-squares linear regression.