Use of vertically resolved plasma emission as an indicator for flagging matrix effects and system drift in inductively coupled plasma-atomic emission spectrometry

Abstract

Vertically resolved measurement of analyte emission was investigated as an on-line indicator for flagging matrix effects and system drift in inductively coupled plasma-atomic emission spectrometry. The method is based on the fact that plasma behavior and excitation conditions are heterogeneous along the ICP vertical axis. As a result, the relative magnitude and even the direction of the change in emission intensity caused by a matrix effect or system drift are not constant, but are functions of observation height in the plasma. Since the determined concentration of an analyte in a sample is proportional to the measured intensity, any change in matrix effects or system drift along the vertical profile will similarly shift the determined concentration, allowing the drift or interference to be detected. It was verified that the new method can successfully flag matrix interferences caused by a change in plasma conditions (so-called plasma-related matrix effects), a change in sample aerosol generation or transport (so-called sample-introduction-related matrix effects) or spectral interference from emission lines of the matrix. Similarly, the method responded effectively to system drift caused by a change in sample throughput, central-channel gas flow and plasma forward power.

Evaluation of Matrix Effects of Polycarboxylic Acid Introduction in Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES)

“…27,38−40 In contrast, the copper atomic lines did not show the same sensitivity under similar conditions. [38][39][40] In a certain degree, some of the described effects were also noted in present study of polycarboxylic acid matrices. Observation of Cd and Cu lines intensity showed the different magnitude of the effects caused by tartaric, citric and dipicolinic acid introduction into plasma.…”

Carbon-, sulfur-, and phosphorus-based charge transfer reactions in inductively coupled plasma–atomic emission spectrometry

“…Chan and Hieftje highlighted that matrix effects show a strong spatial dependence and, hence, plasma spatial profiling is a useful tool to flag matrix effects for both radially [28][29][30] and axiallyviewed ICP-AES [31,32]. Although a specific instrument configuration is required to obtain a detailed cross sectional emission profile, our instrument can provide some limited plasma ) containing solutions.…”

GGR Biennial Review: Atomic Absorption, Inductively Coupled Plasma‐Atomic Emission Spectrometry, Neutron Activation Analysis and X‐Ray Fluorescence Spectrometry Review for 2008–2009

“…The coupling of radiofrequency energy to a probe coil placed inside the ICP torch box also changed in the presence of matrix. A second paper by Chan and Hieftje (2008b) demonstrated that the vertically resolved analyte emission pattern could be used as an indicator of matrix‐induced changes in plasma conditions, sample aerosol generation or transport, and spectral interference. Another study of matrix effects from Al, Ca and Mg using axially viewed ICP‐AES proposed a global qualitative explanation for the action matrix in ICP‐AES analysis (Larrea et al.…”