Levitated droplet and dried droplet preparations involving ionic and common matrices applied to bacteriorhodopsin sequence coverage

This thesis describes an investigation of the potential for ionic compounds to function as host compounds, termed the matrix, to provide improved detection of intact membrane proteins, and peptides from membrane protein digests using matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In one mode of sample preparation referred to as wall-less sample preparation (WaSP), the sequence coverage obtained for a model protein, bacteriorhodopsin was complementary to that of using the traditional sample preparation methodology, dried droplet. An objective of this work was to determine if a correlation existed between the properties of the ionic compounds used and the sequence coverage obtained. Chemical and physical properties of the ionic compounds found to increase the sequence coverage include organic base having greater aromaticity, low pH starting solutions, and crystalline or amorphous appearance of the prepared sample material.