2025/08/21 by Davis Bryars, Munmun Jahan, Kayla Hahn +4 · 1 voice · 2 citations
Chemistry · Engineering · Physics and Astronomy · #Analytical Chemistry (journal) #Atomic and Subatomic Physics Research #Chemistry #Emission spectrum #Environmental chemistry #Gas Sensing Nanomaterials and Sensors #Materials science #Nuclear Physics and Applications #Plasma #Resolution (logic) #Spectral line #Vaporization
paper · doi:10.1177/00037028251374696
published in Applied Spectroscopy 80(1), 71-82 (SAGE Publishing)
openalex created_date 2025/08/21 · openalex publication_date 2025/08/21 · openalex updated_date 2026/07/14
We developed a sensor called the Submerged Plasma for Isotopic Detection and Elemental Resolution (SPIDER) probe, which uses an atmospheric pressure glow discharge below the surface of liquids to excite species in the liquid. Through emission spectroscopy of molten salts, liquid metals, and heavy water, we demonstrated the SPIDER probe’s high resolution, accuracy, and versatility. We successfully identified trace concentrations of transition and rare-earth metals in molten salts and detected the isotopic shift of the H <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mrow/> <mml:mi>β</mml:mi> </mml:msub> <mml:mo stretchy="false">→</mml:mo> </mml:math> D <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mrow/> <mml:mi>β</mml:mi> </mml:msub> </mml:math> emission line. Our analysis revealed unconventional spectral alkali line shapes, indicating two competing excitation modes: film explosion and droplet vaporization. The film explosion mode, characterized by dense plasma, exhibited self-reversal and broadband continuum emission, while the droplet vaporization mode, associated with diffusive plasma, produced narrow-line emissions. By analyzing circuit transients alongside individual plasma events, we observed that film explosions generate higher currents, likely due to a shorter plasma length as the current preferentially flows through the thin liquid layer. Altogether, our results highlight the SPIDER probe’s efficacy and flexibility, making it well-suited for online material quantification of liquids in extreme environments.