MeSH headings : Artifacts; Barium Sulfate / chemistry; Fractional Precipitation; Mass Spectrometry / methods; Nitrates / chemistry; Oxygen Isotopes / analysis; Reproducibility of Results; Sensitivity and Specificity

TL;DR: The fraction of coprecipitated nitrate appears to increase with decreasing pH and is also affected by the nature of the cations in the precipitating solution and the size of the oxygen isotope artifact in sulfate depends both on the amount ofCoprecipitate nitrate and the delta(18)O and Delta(17)O values of the nitrate, both of which can be highly variable. (via Semantic Scholar)