Controlling the dissociation of peptide ions using laser desorption/chemical ionization Fourier transform mass spectrometry

Abstract

classified as both chemical (preferential sputtering) and physical (surface roughness) effects. ACKNOWLEDGMENTWe gratefully acknowledge both Pat Sullivan and Frank Dalton for helpful discussions.Registry No. Fe(vbpy)2(CN)2 (homopolymer), 119058-92-3; vbpy (homopolymer), 82441-96-1; silver nitrate, 7783-99-5.

Electrospray‐assisted laser desorption/ionization mass spectrometry for direct ambient analysis of solids

“…Therefore, the post‐ionization of neutrals has become of growing interest, as this approach promises not only the detection of different analytes, but also increased sensitivity. The use of a number of different ionization techniques for post‐ionization of laser‐desorbed analytes, such as electron ionization (EI),4–6 chemical ionization (CI),7–10 Na + ‐cationization,11 corona discharge atmospheric pressure chemical ionization (APCI),12, 13 Ni‐63 APCI,14 resonance‐enhanced multi‐photon ionization (REMPI),15 inductively coupled plasma (ICP),16, 17 and vacuum‐UV photoionization (PI),18 have been explored in the past.…”

“…Post‐ionization of laser‐desorbed material has resulted in the development of unique applications 4–18. However, in the absence of matrix, the technique is still limited to the study of relatively low molecular weight compounds, and attempts to analyze proteins have largely failed.…”

Influence of Amino Acid Composition and Phosphorylation on the Ion Yields of Peptides in MALDI-MS

“…In the following years, several different approaches were used to ionize the neutral molecules produced after laser desorption events. These methods include chemical ionization [9][10][11], electron ionization [12], laser ionization [13][14][15], and electrospray ionization [16]. The decoupling of desorption and ionization processes allows for the individual optimization of the two steps with increased gas-phase ion formation efficiency.…”

The reactions of ground state Cu+ and Fe+ with the 20 common amino acids

“…Collision-activated dissociation [10][11][12], photodissociation, [13][14][15], and surface-induced dissociation [16][17][18] have been used to induce the fragmentation of peptides and proteins. As an alternative to these approaches, we have developed methods to control the ionization and fragmentation of biomolecules by using gas-phase chemical reactions [19][20][21][22][23][24][25][26][27]. To accomplish this, reagent ions are formed and stored in the analyzer region of a Fourier transform mass spectrometer, and laser-desorbed neutral biomolecules are allowed to react with these ions.…”

“…To accomplish this, reagent ions are formed and stored in the analyzer region of a Fourier transform mass spectrometer, and laser-desorbed neutral biomolecules are allowed to react with these ions. This two-step method for ion formations, called laser desorption-chemical ionization (LD-eI) [19][20][21][22][23][24][25][26][27], requires the production of gas phase, intact, neutral molecules, in contrast to most laser desorption mass spectrometry experiments in which ions are desorbed directly and detected. To efficiently desorb intact neutral molecules of peptides for chemical ionization studies, the technique of substrate-assisted laser desorption (SALD) was developed [21].…”