PNNL

Abstract

A new ion deposition apparatus was designed and constructed in our laboratory. Our research objectives were to investigate interactions of biomolecules with hydrophilic and hydrophobic surfaces and to carry out exploratory experiments aimed at highly-selective deposition of spatially defined and uniquely selected biological molecules on surfaces. The apparatus includes a high-transmission electrospray ion source, quadrupole mass filter, bending quadrupole that deflects the ion beam and prevents neutral molecules originating in the ion source from impacting the surface, an ultrahigh vacuum (UHV) chamber for ion deposition by soft landing, and a vacuum-lock system for introducing surfaces into the UHV chamber without breaking vacuum. Ex situ analysis of surfaces following soft-landing of mass-selected peptide ions was performed using 15 keV Ga+ time-of-flight secondary ion mass spectrometry (TOF-SIMS) and grazing incidence infrared reflection-absorption spectroscopy (IRRAS). It will be shown that these two techniques are highly complementary methods for characterization of surfaces prepared with a range of doses of mass-selected biomolecular ions.