2.3 Calibration Standards and Quality Control (QC) Samples
10 mg of imatinib was precisely weighed and then dissolved with methanol to prepare imatinib calibration standard and QC stock solution with a concentration of 1 mg/mL. The calibration standard stock solution was diluted with 50% methanol into a series of calibration standard solutions with concentrations of 2000, 1000, 500, 200, 100, 50, 20 and 10 ng/mL, and the QC stock solution was diluted into the solutions with concentrations of 1800, 300, 30 and 10 ng/mL in the same way. 10 mg of IS was precisely weighed and then dissolved with methanol to prepare IS stock solution with a concentration of 1 mg/mL. The IS solution of 10 ng/mL was obtained by dilution with acetonitrile used as precipitation agent.