6420 series triple quadrupole tandem mass spectrometer

UHPLC-MS/MS with Agilent 1290 UHPLC system and 6420 series Triple-Quadrupole Tandem Mass Spectrometer (Agilent, Santa Clara, CA, USA) equipped with electrospray ionization (ESI) source operating in positive-ion mode was used to monitor the mixed compounds. Instrument control and data acquisition were performed on the MassHunter Agilent Software (version B.07.00).
Five probes and IS were separated using a ZORBAX Eclipse Plus C18 Rapid Resolution HD column (2.1 mm × 50 mm, 1.8 μm) at a constant temperature of 30°C. The mobile phase consisting of A (0.1% formic acid-water, v/v) and B (acetonitrile) was ultrasonic degassed before use. The optimal gradient elution program was as follows: 0–0.3 min, 30% B; 0.3–1.3 min, linear from 30% to 50% B; 1.3–1.8 min, linear from 50% to 95% B; 1.8–2.8 min, 95% B. The posttime was 1.0 min for equilibration of the column and the total runtime was 3.8 min. The flow rate was 0.4 ml/min.
The desolvation gas (nitrogen) flow was set to 10 L/h: the capillary voltage: 4000 V; nebulizing gas and drying gas (both nitrogen): 45 psi and 350°C, respectively. The multiple reaction monitoring (MRM) mode with m/z 180.1→109.9 for phenacetin, m/z 271.1→91.0 for tolbutamide, m/z 346.1→135.9 for omeprazole, m/z 268.2→115.9 for metoprolol, m/z 326.1→290.8 for midazolam, and m/z 237.1→194.0 for IS was used for quantitative analysis.

Agilent 1290 UHPLC system and 6420 series Triple‐Quadrupole Tandem Mass Spectrometer (Agilent Corporation) maintained at 35°C with a ZORBAX Eclipse Plus C18 column (1.8 μm, 2.1 × 50 mm). The mobile phase was a gradient elution program consisting of solvent A with solvent B at a flow rate of 0.4 ml/min. Mobile phase A was 0.1% formic acid in water (v/v), and mobile phase B was acetonitrile. The optimal gradient elution program was as follows: 0–0.5 min, linear from 80% to 5% A; 0.5–1.5 min, 5% A; 1.5–1.6 min, linear from 5% to 80% A. The post‐time was 1.3 min for equilibration of the column and the total runtime was 1.8 min. The mass spectrometer was acquired in an ESI‐positive mode with multiple reaction monitoring (MRM). Instrument control and data acquisition were performed on the MassHunter Agilent Software (version B.07.00).
The desolation gas (nitrogen) flow was set to 10 L/h: the capillary voltage: 4000 V; nebulizing gas and drying gas (both nitrogen): 45 psi and 350°C, respectively. The MRM mode with m/z 282.2→76.9 for C1632 and m/z 282.1→194.0 for IS was used for quantitative analysis.