Open AccessA Simple Elemental Sulfur Reduction Method for Isotopic Analysis and Pilot Experimental Tests of Symmetry‐Dependent Sulfur Isotope Effects in Planetary Processes
Author(s) -
Lin Mang,
Thiemens Mark H.
Publication year - 2020
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2020gc009051
Subject(s) - sulfur , isotopes of sulfur , mass independent fractionation , reagent , isotope analysis , isotope , hydrogen sulfide , chemistry , sulfide , mass spectrometry , elemental analysis , stable isotope ratio , fractionation , isotope fractionation , analytical chemistry (journal) , inorganic chemistry , geology , environmental chemistry , organic chemistry , physics , chromatography , nuclear physics , biochemistry , oceanography , amino acid , methionine
Recent insights into fundamental mechanisms underlying quadruple stable sulfur isotope ( 32 S, 33 S, 34 S, and 36 S) mass‐independent fractionation (S‐MIF) chemistry and potential implications for planetary processes highlight the urgent need of conducting laboratory experiments to delineate the chemical physics of S‐MIF. Elemental sulfur (S 0 ), a ubiquitous component in the atmospheres of early Earth and Mars, is a major product or reactant in most experiments. Developing different chemical protocols for isotopic analysis is consequently of utility. The reduction of S 0 to hydrogen sulfide (H 2 S) is the first step of the fluorination method for isotopic analysis, but existing S 0 reduction methods require relatively long chemical reagent preparation time. Here we present an operationally simple and rapid method for reducing S 0 to H 2 S directly by “Thode solution.” External uncertainties of our method for δ 34 S, Δ 33 S, and Δ 36 S measurements (associated with reduction, fluorination, purification, and mass spectrometer analysis) are 0.3‰, 0.01‰, and 0.2‰, respectively, comparable with traditional methods. This new technique was used to determine quadruple stable sulfur isotope compositions of product S 0 in a set of pilot experiments designed to investigate possible symmetry‐dependent isotope effects in planetary‐relevant elemental sulfur recombination reactions. Differences in Δ 33 S and Δ 36 S between initial and produced S 0 are slightly larger than analytical errors, shedding new light into the role of sulfur recombination reactions in S‐MIF. Our study offers a practical approach for measuring multiple isotopic compositions of S 0 in laboratory and natural samples and creates new opportunities for deepening understanding of S‐MIF signatures in Archean rocks and Martian meteorites.