PNNL

Abstract

Inductively coupled plasma mass spectrometry (ICPMS) is a powerful technique for accurately and precisely measuring particles. Built on instrumentation developed for steady state signals, detection and quantification of particles with ICPMS instruments is based on signal intensity raising above background within an integration window. The research presented in this article utilized single ion detection on time to identify and quantify particles based on the temporal signature of a burst of ions from each particle rather than intensity increases in defined integration periods. The new method allows for fast, efficient, and sensitive detection of micro and nanoparticles and provides a powerful means to discriminate against non-particle backgrounds. We tested the method with standard gold nanoparticles, uranium particles in solution and from an aerosol created during laser ablation, and iron nanoparticles. The results show efficient detection of nanoparticles separated from interfering background and down to single ion detection of minor uranium isotopes.