Direct determination of actinides in solid samples with electrothermal vaporization and inductively coupled plasma-mass spectrometry

Direct sampling of solids is very useful in trace-level analysis, because sample preparation procedures are minimized, and losses of trace elements and introduction of contaminants can be avoided. The objective of this work was to develop a universal methodology for soil analysis by integrating electrothermal vaporization and inductively coupled plasma-mass spectrometry (ETV-ICP-MS) to vaporize solid samples with any inorganic matrix. This methodology required no sample pretreatment and minimized sample size. The rationale was to use chemical modifiers such as CHF{sub 3} to form metal fluorides with much lower boiling points than their other forms (such as oxides and carbides). Given sufficiently high temperatures and long reaction times, samples in other chemical forms are converted to elemental halides and vaporized. Changing the nature of the sample makes the vaporization process independent of sample matrix. The characterization and application of ETV-ICP-MS for the determination of actinide elements in soil samples will be described. In addition, effects of chemical modifiers, optimization parameters, limits of detection, calibration plots, and matrix effects will be presented.