The Eighteenth Missouri

The effect of sulfate‐δ18O upon on‐line sulfate‐δ34S analysis, and implications for measurements of δ33S and Δ33S

“…18,19 In a fashion analogous to the use of SO 2 to perform d 34 S analyses, SO 2 may potentially be used to perform d 33 S analyses. Following a previous treatment, 3 it can be shown that:…”

“…On-line d 34 S analysis of sulfur-bearing samples requires conversion of sample sulfur into SO 2 gas, which is then analyzed by stable isotope ratio mass spectrometry. 1,2 Previous theoretical and experimental considerations have demonstrated that the values of both SO 2 -d 18 O and SO 2d 34 S have an impact upon the relative beam intensities for the various SO 2 isotopomers, 3 which requires consideration of SO 2 -d 18 exchanging the sulfate-oxygen in three aliquots of concentrated sulfuric acid with waters with three different d 18 O compositions. Concentrated H 2 SO 4 (0.5 mL; certified ACSplus, Fisher Scientific) was added to 6 mL of each of the three waters in polypropylene bottles, to produce solutions of approximate composition of 1.5 molal H 2 SO 4 , and approximate pH of À0.5.…”