Secondary ion yields for vacuum-type electrospray droplet beams measured with a triple focus time-of-flight analyzer.

Rationale: We previously developed a massive cluster ion beam gun for secondary ion mass spectrometry (SIMS) in which the primary beam source is a vacuum electrospray. The secondary ion yields produced by this method had not yet been measured with a commercial time-of-flight (TOF) secondary ion mass spectrometer, and the ionization performance was unknown.

Methods: A vacuum-type electrospray droplet ion gun was connected to a triple-focus TOF analyzer.