Determination of 5-aminoimidazole-4-carboxamide in human plasma by ion-pair extraction and LC–MS/MS

A liquid chromatography/tandem mass spectrometry (LC–MS/MS) method was established for the determination of 5-aminoimidazole-4-carboxamide (AICA) in human plasma. The method included a solvent extraction of AICA as an ion pair with 1-pentanesulfonate ion and a separation on a Hypersil ODS2 column with the mobile phase of methanol–water (68:32, v/v). Determination was performed using an electrospray ionization source in positive ion mode (ESI+). Multiple reaction monitoring (MRM) was utilized for the detection monitoring m/z at 127 → 110 for AICA, and 172 → 128 for IS. The calibration curve was linear within a range from 20 to 2000 ng/mL and the limit of quantity for AICA in plasma was 20 ng/mL. RSD of intra-assay and inter-assay were no more than 5.90% and 5.65%.