Development of methods for mass spectrometry analysis of proteins in supernatants harvested from in vitro human lung cells (A549)

Proteins are primarily responsible for functionalizing cells and, with respect to an initiative in soft ionization mass spectrometry (MS), the relative abundances of selected proteins have been used as indicators of normal or stressed physiological states. Methods developed for this thesis describe the use of matrix assisted laser desorption ionization time of flight (MALDI-ToF) MS to monitor the ion signals of C-X-C motif chemokine 5 and ubiquitin protein. Identification of these ion signals were carried out by performing additional experiments using liquid chromatography interfaced to an electrospray ionization (LC-ESI) equipped MS capable of tandem MS. A total of 78 proteins were identified by LC-ESI tandem MS, but not all corresponded to MALDI-MS data. In addition to the use of commercially available instrumentation, a separate study was performed to investigate the potential for an AC trap to generate molecular ions from a single levitated droplet having undergone Coulomb explosion.