Geoanalysis using plasma spectrochemistry - milestones and future prospects

Area of Science:

• Geochemistry
• Analytical Chemistry
• Spectroscopy

Background:

• Plasma spectrochemistry is crucial for geoanalysis, but sample decomposition methods present challenges.
• Acid decomposition yields low salt content but poor recoveries for some samples.
• Alkali fusions offer total decomposition but high salt content causes interferences in inductively coupled plasma (ICP) systems.

Purpose of the Study:

• To review plasma spectrochemistry techniques in geoanalysis.
• To evaluate instrumental developments, calibration, interferences, and analytical performance.
• To assess practical determination limits based on salt tolerances.

Main Methods:

• Review of recent instrumental developments in plasma spectrochemistry.
• Evaluation of calibration strategies and spectral/matrix interferences.
• Analysis of direct solid sample introduction methods: DC arc emission spectroscopy (DC-AES), slurry nebulization (SN), spark ablation (SA), laser ablation (LA), and glow discharges (GD).

Main Results:

• ICP-atomic emission spectrometry (AES) is suitable for major, minor, and abundant trace elements.
• ICP-mass spectrometry (MS) is preferred for trace elements and isotopic analysis, enhancing geochemical problem-solving.
• Direct solid sample introduction methods enable analysis of bulk samples, minerals, and inclusions.

Conclusions:

• The choice between ICP-AES and ICP-MS depends on the analytical target (major vs. trace elements).
• Salt tolerance is a critical factor in determining practical limits of analysis.
• Direct solid analysis techniques significantly expand the scope of geoanalysis.