SINGLE-PARTICLE CHARACTERIZATION BY TIME-OF-FLIGHT MASS-SPECTROMETRY

We have built a particle analyzer capable of real-time detection and c haracterization of individual particles. Particle analysis is accompli shed by pulsed laser ablation of a particle followed by time-of-flight mass spectrometry of the resulting atomic and molecular ions. The det ected ions are characteristic of a particle's molecular composition. P articles of different sizes (0.02-10 mu m) and compositions (ammonium sulfate, silica, rubidium nitrate, and cesium nitrate) have been detec ted and characterized. Even refractory materials, e.g. silica, are eas ily detected.