Luna omega 1.6 m polar c18 10 column

The Shimadzu Nexera X2 (Shimadzu, Kyoto, Japan) ultra-high-performance liquid chromatograph (UHPLC) system coupled to the QTRAP^® 4500 triple-quadrupole mass spectrometer (Sciex, Framingham, MA, USA) was used for sample analysis.
The UHPLC system was equipped with a Luna^® Omega 1.6 µm Polar C18 10 column (100 mm × 2.1 mm, Phenomenex, Torrance, CA, USA) integrated with a guard column of the same type at 35 °C. The mobile phase consisted of two eluents, 0.075% formic acid (A) and 0.05% formic acid in acetonitrile (B). The samples were separated under the following gradient conditions: 92% A (0.01–4.00 min), 90% B (4.01–6.30 min), and 92% A (6.31–8.00 min), at a flow rate of 0.32 mL/min. A volume of 3 µL of sample extract was injected. The mass spectrometric analysis was performed using triple-quadrupole detection in positive ion mode (ESI+). The instrument was set to collect data in multiple reaction monitoring mode (MRM) for quantification. The ion transitions and mass parameters monitored for each analyte are listed in Table 1. The following MS/MS parameters were used for multi-compound analysis: source temperature = 470 °C; IonSpray voltage = 5500 V; Curtain Gas = 20 psi; ion source gas 1 = 40 psi; ion source gas 2 = 50 psi; Entrance potential = 10 V.