Demian Ifa

Assistant professor, Chemistry department, York University

Mass Spectrometry Imaging under Ambient Conditions

Mass spectrometry imaging (MSI) has emerged as an important tool in the last decade and it is beginning to show potential to provide new information in many fields owing to its unique ability to acquire molecularly specific images and to provide multiplexed information, without the need for labeling or staining. In MSI, the chemical identity of molecules present on a surface is investigated as a function of their spatial distribution. In addition to now standard methods involving MSI in vacuum, recently developed ambient ionization techniques allow MSI to be performed under atmospheric pressure on untreated samples outside the mass spectrometer. In desorption electrospray ionization (DESI), a spray of charged droplets is directed at the sample creating a thin film of solvent on the surface. Further spray droplets collide with the solvent film and splash secondary droplets containing dissolved analytes into the air and from there they are directed into the mass spectrometer. DESI-MS imaging has become increasingly attractive due to its simplicity and the reduced sample preparation steps compared with vacuum based imaging techniques. Recent advances and applications of MSI under ambient conditions will be presented.