Icp-ms analyses in hydro-organic matrices: introduction device selection and operating parameters optimization
Abstract
In the field of nuclear waste management, actinides and lanthanides speciation studies are mainly carried out by chromatographic techniques, involving hydro-organic mobile phases. Introduction of such matrices into ICP sources is complex and results in ICP analytical performances degradation, such as plasma instabilities, sensitivity losses, spectral and non-spectral interferences, contaminations, cone and injector orifices clogging and even extinction. Technical constraints induced by nuclearized spectrometers, mandatory to handle radioactive samples, render this introduction even more challenging.Various introduction devices are commercialized to address the issue of liquid matrices introduction in ICP with the aim to improve the analytical performances, while facilitating the experiments (high plasma tolerance, robust conditions, etc.). Additional operating parameters optimization is needed to conserve the analytical performances using such matrices. The goal of this study is first to better understand the effects and interactions of the operating parameters on signal sensitivity and stability, obtained for lanthanides in hydro-organic matrices involving various amounts of acetonitrile, hardly compatible with ICP sources. For that, a Peltier-cooled cyclonic spray chamber with O2 introduction port (PC3, Elemental Scientific) has been chosen. Then, three introduction devices with different designs and adapted to nuclear instrumentations, have been used whilst remaining easy to handle a cyclonic spray chamber (considered as the basic configuration), the PC3 and a desolvation device (Apex from Elemental Scientific). These devices are compared according to the maximum amount of organic matrices able to be introduced in ICP-MS and regarding robust analytical performances; the sensitivity and stability measured for each analyte; and finally, their ease-of-use.
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