Investigation of sample introduction- and plasma-related matrix effects in inductively coupled plasma spectrometry applying single analyte droplet and particle injection

Abstract

Analyte atomization in an inductively coupled argon plasma is studied with spatial and temporal resolution by simultaneous side- and end-on emission spectroscopy. The samples are either introduced as single monodisperse microdroplets of analyte solution or in form of spherical nano- or microparticles with narrow size distributions embedded in microdroplets. While end-on spectroscopy provides quantitative information on the total atomization process during the transport through the ICP of a single injection event, side-on measurements deliver the spatial positions of the processes. It is shown that there are significant spatial shifts of the position of analyte atomization in dependence on injector gas flow, droplet size, analyte mass, and the mass of accompanying elements. These shifts have direct influence on the size of the analyte clouds at a particular position in the ICP, e.g., at the position of the sampler of a mass spectrometer in ICP-MS, and, therefore, on the detection efficiency of this technique. Furthermore, the dynamic processes of analyte ionization as well as element dependent diffusion were studied with spatial and temporal resolution.