Some aspects of space-charge effect calculation in high-resolution mass spectrometry.

A variational 3D approach to the problem of simulating stationary distributions of ions in the radiofrequency low-vacuum ion traps with regard to Coulomb interaction and collisions of ions with buffer gas molecules is proposed. The software developed in the course of this work is employed to study the structure of stationary ion ensembles in the radiofrequency ion traps of various types. The effect of high-frequency and constant voltages, space-charge density, and buffer gas temperature on the formation of stationary distributions in the radiofrequency ion traps and their limiting capacitance is investigated.

Surface-assisted laser desorption/ionization mass spectrometry with a rotating ball interface.

A rotating ball interface for surface-assisted laser desorption/ionization (SALDI) mass spectrometry was designed and tested. One side of the ball was exposed to atmospheric pressure and the other to the vacuum in a time-of-flight mass spectrometer. Analytes (arginine, atenolol, reserpine, tofisopam, and chloropyramine) were applied using electrospray to a silicon substrate on the atmospheric side, the ball was rotated 180°, and the analyte was desorbed on the vacuum side using a pulsed, 200 Hz, 355 nm laser.

Gas chromatography/surface-assisted laser desorption ionization mass spectrometry of amphetamine-like compounds.

A variety of amphetamine-like compounds were analyzed by gas chromatography/surface-assisted laser desorption ionization mass spectrometry, GC/SALDI-MS. In the SALDI method, compounds are adsorbed on a solid SALDI substrate and directly ionized from the substrate by means of a laser pulse. The interfacing of a SALDI ion source with a gas chromatograph is presented here for the first time.

On the role of defects and surface chemistry for surface-assisted laser desorption ionization from silicon.

The generation of ions from silicon substrates in surface-assisted laser desorption ionization (SALDI) has been studied using silicon substrates prepared and etched by a variety of different methods. The different substrates were compared with respect to their ability to generate peptide mass spectra using standard liquid sample deposition. The desorption/ionization processes were studied using gas-phase analyte deposition.