ABSTRACT
While the applications of ambient ionization mass spectrometry have been widely reported in areas such as biomedical, homeland security/forensics, and pharmaceutical process monitoring, the evaluation and the use of these techniques for absorption,
distribution, metabolism, and excretion (ADME) studies on drugs or drug metabolites have emerged more slowly mostly due to two reasons. First, samples for ADME studies are generally in complex biological matrixes, and, therefore, ion suppression is a concern if samples are directly subject to ambient ionization methods without any sample preparation. Second, most of the ADME applications are quantitative in nature. Unlike conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based techniques where samples with a well-de ned volume are injected for analysis, sampling reproducibility can be a challenge for ambient ionization methods since there is no de ned sampling volume. In spite of the challenges, the unique and attractive features of ambient ionization methods such as real-time analysis without sample preparation or vacuum constraints have driven the research interest in this area and publications in this eld are emerging.
