NanoLC-MS/MS was performed using a TripleTOF 5600 system (AB Sciex) equipped with an HTC-PAL autosampler (CTC Analytics). Loaded samples were separated on a self-pulled analytical column (150 mm length, 100 μm internal diameter) using a Dionex Ultimate 3000 RSLC Nano System. The mobile phases consisted of (A) 0.5% acetic acid with 5% DMSO and (B) 0.5% acetic acid in 80% acetonitrile with 5% DMSO (Hahne et al., 2013). The linear gradient condition was 5%–99% B for 10 min, 99% B for 5 min, and 5% B for 30 min at a flow rate of 500 μL/min. A spray voltage of 2,300 V was applied. The MS scan range was 100–1,500 m/z every 0.25 s. Blank runs were inserted between different samples. All raw data files from the TripleTOF 5600 system were analyzed by PeakView software version 2.1 (AB Sciex). Extracted-ion chromatograms were observed with ±0.01 m/z width for each of caffeine (m/z = 195.0867), cimetidine (m/z = 253.123), propranolol (m/z = 260.1645), epinastine (m/z = 250.13387), prazosin (m/z = 384.16663), quinidine (m/z = 325.19105), sulpiride (m/z = 342.1482), trazodone (m/z = 372.15856), antipyrine (m/z = 189.10224), and carbamazepine (m/z = 237.10224).
