2.2 Instrumentation and Conditions
Analysis of imatinib in human plasma was achieved with the usage of ultra-high performance liquid chromatography-mass spectrometry tandem system (AB Sciex, USA) consisting of quaternary ultra-high pressure infusion pump (ExionLC AD), column oven (ExionLC AC), autosampler (ExionLC AD) and AB Sciex Triple QuadTM 5500 mass spectrometer (Qtrap 5500). Imatinib and IS were separated on Waters BEH C18 column (2.1×50 mm, 1.7 µm; Waters, USA) at a temperature of 45°C. The mobile phase consisted of formic acid (0.1%) and acetonitrile with constant flow rate of 0.3 ml/min. Imatinib and IS were separated under gradient elution as follows: 0-6 min, 20%-80% B; 6-8 min, 80% B; 8-8.1min, 80%-20% B; 8.1-9 min, 20%.
The ionization of imatinib and IS was performed on an ESI+ source and monitored in MRM mode with the m/z of 494.3→394.1 and 398.2→212.1, respectively. Product ion spectrum of the analytes was indicated in Figure 1. The ion source parameters comprised of ion source temperature of 500℃, capillary voltage of 5500 V, Gas1 50 psi, Gas2 50 psi. The voltages of collision energy (CE) for imatinib and IS were optimized as 36 V and 41 V, respectively. The voltages of declustering potential (DP) were 100 V and 70 V.