Mercury Lα1 High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy: A Versatile Speciation Probe...

Area of Science:

• Environmental Chemistry
• Toxicology
• Spectroscopy

Background:

• Mercury is a naturally occurring element crucial to biogeochemical cycles, but anthropogenic pollution, especially from fossil fuels, increases environmental emissions.
• Understanding mercury's environmental fate is vital and heavily dependent on its chemical speciation.
• Conventional X-ray absorption spectroscopy (XAS) is useful for in situ speciation but suffers from poor energy resolution.

Purpose of the Study:

• To systematically examine mercury Lα1 high energy resolution fluorescence detected XAS (HERFD-XAS) as a method for mercury chemical speciation.
• To quantitatively compare HERFD-XAS with conventional Hg LIII-edge XAS.
• To assess the applicability of HERFD-XAS for environmental and life science research.

Main Methods:

• Systematic examination of mercury Lα1 HERFD-XAS.
• Quantitative comparison with conventional Hg LIII-edge XAS.
• Spectral analysis of various mercury compounds and simulation using density functional theory.

Main Results:

• Chemical shifts in Lα1 X-ray fluorescence energy can be neglected for mercury, allowing HERFD-XAS to function as a high-resolution XAS.
• Density functional theory provides adequate simulations for mercury HERFD-XAS spectra.
• Significant improvements in speciation for complex mixtures and enhanced background rejection for low mercury concentrations were demonstrated.

Conclusions:

• Mercury Lα1 HERFD-XAS is a powerful tool for mercury chemical speciation, offering superior resolution compared to conventional methods.
• The technique shows promise for analyzing complex environmental samples and detecting low mercury concentrations.
• HERFD-XAS provides a valuable advancement for environmental and life science research involving mercury analysis.