Comparison of sample preparation methods for stable isotope analysis of dissolved sulphate in forested watersheds

TitleComparison of sample preparation methods for stable isotope analysis of dissolved sulphate in forested watersheds
Publication TypeJournal Article
Year of Publication2012
AuthorsKang, P-G, Mayer, B, Mitchell, MJ
JournalIsotopes in Environmental Health Studies
Volume48
Issue3
Pagination410 - 420
Date Published2012///
KeywordsIsotope Measurements, Isotope Ratio Mass Spectrometry, Methods and Equipment, Natural Abundances, Oxygen-18, Sample Preparation Methods, Sulphate, Sulphur-34, Watersheds
Abstract

Pretreatment methods for measuring stable sulphur (δ34S) and oxygen (δ18O) isotope ratios of dissolved sulphate from watersheds have evolved throughout the last few decades. The current study evaluated if there are differences in the measured stable S and O isotope values of dissolved sulphate from forested watersheds when pretreated using three different methods: Method 1 (M1): adsorb sulphate on anion exchange resins and send directly to isotope facility; Method 2 (M2): adsorb sulphate on anion exchange resins, extract sulphate from anion exchange resins, and send the produced BaSO4 to the isotope facility; and Method 3 (M3): directly precipitate BaSO4 without anion exchange resins with the precipitates being sent to the isotope facility. We found an excellent agreement of the δ34Ssulphate values among all the three methods. However, some differences were observed in the δ18Osulphate values (M1 versus M2:−1.5 ‰; M1 versus M3:−1.2 ‰) associated with possible O contamination before isotope measurement. Several approaches are recommended to improve the pretreatment procedures for δ18Osulphate analysis.

Short TitleIsotopes in Environmental Health Studies