Electrospray Ionization (ESI) and Matrix-Assisted Laser Desorption Ionization (MALDI) are conventional, soft ionization techniques for large biomolecules. ESI produces multiple charges which is advantageous for high resolution and mass accuracy measurements performed on instruments with mass limitations, whereas MALDI produces singly-charged ions. Solvent-Assisted Inlet Ionization (SAII) and Laserspray Inlet Ionization (LSII) are novel ionization techniques similar to conventional ionization sources; however they do not require voltage and form ions inside a heated AP-to-vacuum inlet tube. Both of these novel techniques produce a charged envelope analogous to ESI. Myoglobin, ubiquitin, and cytochrome-c were prepared in low micromolar concentrations in various solvents. Additives such as acetic acid, formic acid, sulfalane, dimethyl sulfoxide and 3-nitrobenzyl alcohol were added to enhance the charge envelope. The goal is to enhance the multiple charges by utilizing supercharging and protein-denaturing additives in the inlet ionization techniques as well as determining if the mechanisms are comparable to ESI.

Investigating effects on charge-state distributions for protein analysis in novel ionization techniques

244th National Meeting (2012)

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