Droplet Phase Ion-Ion Chemistry
thesisposted on 01.05.2016, 00:00 by Joshua A. Henry
The purpose of the research performed this semester was to replicate the results of a study undertaken by Cotham et al. and to change the method used to improve the measurement of the amino acid sequence of a peptide by Mass Spectrometry. The study in question used Collision Induced Dissociation (CID) to initiate a droplet phase ion/ion Schiff's base reaction followed by photodissociation with UV light. The reaction involved protonated peptides and the reagent 4-formyl-1,3-benzenedisulfonic acid (FBDSA). The two solutions were brought together in the droplet phase via positive (peptide) and negative (FBDSA) electrospray. We are testing whether collision induced dissociation achieved via the quadrupole ion trap Mass Spectrometer's (our detector) MS/MS/MS capacity can be used in place of the two step CID plus photodissociation with UV light process. The expected outcome of our research is to determine the effectiveness of our approach in obtaining the peptide sequence while at the same time increasing the reaction rate to increase compatibility with an LC separation time frame. An underlying goal is potentially find a way to sequence peptides that are produced by digestion methods other that trypsin. If this was successful it could facilitate viewing of larger peptides and decrease the analysis time for protein identification by MS.