Soft-Landing of Peptides onto Self-Assembled Monolayer Surfaces
Mass-selected peptide ions produced by electrospray ionization were deposited as ions by soft-landing onto fluorinated and hydrogenated self-assembled monolayer surfaces (FSAM and HSAM) surfaces using a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially designed for studying interactions of large ions with surfaces. Analysis of the modified surface was performed in situ by combining 2 keV Cs+ secondary ion mass spectrometry with FT-ICR detection of the sputtered ions (FT-ICR-SIMS). Collision energy dependent data indicated that peptide fragmentation observed in Cs+ SIMS analysis of surfaces modified by soft landing occurred in the analysis step (SIMS) rather than during ion deposition. The peptide ion deposition efficiency showed a gradual decrease with increase in collision energy which parallels the decrease in the Langevin cross section with ion velocity at impact. Peptide ion soft-landing on FSAM surfaces gave twice the sputtered ion signal seen for hydrocarbon self-assembled monolayer (HSAM) surfaces. This indicates stronger interaction of peptide ions with the FSAM surface, in good agreement with larger polarizability of fluorinated hydrocarbons. The efficiency of soft landing of different peptides on the FSAM surface increases with the charge state of the ion, consistent with an ion-polarizable molecule model for the initial stage of soft landing on SAM surfaces.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 876834
- Report Number(s):
- PNNL-SA-43766; JPCAFH; 3584; KC0302020; TRN: US200608%%72
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 110, Issue 4; ISSN 1089-5639
- Country of Publication:
- United States
- Language:
- English
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