Development of New Instrumention (Early Career): Laser Decomposition Isotope Interface (LADII)- Total Isotope Analysis of Nanomolar Amounts of Sulfate and Nitrate

Purdue University, West Lafayette IN

Investigators

Abstract

0929981 Michalski This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This award will fund developing a Laser Decomposition Isotope Interface (LADII) for preparing very small (nanomolar) quantities of compounds for oxygen isotope analysis in sulfate and nitrate. The system to be developed will use a carbon dioxide laser to produce sufficient gas from nonamolar samples to also perform delta 34S, delta 15N and Delta 33S analysis. In addition, triple oxygen isotope analysis will be possible at ~0.2 permil precision. The enhanced precision and smaller sample size will allow oxygen isotope analysis in perchlorate, phosphate and oxalate, which are common contaminants. The PI will also analyze precipitation samples to better understand isotopic distributions which will, in turn, assist in constraining atmospheric chemical transport models. Atmospheric deposition and soil biogeochemistry will be assessed from central Chinese speleothem analysis. Watershed samples from the desert southwest and the central US will be analyzed for sulfate and nitrate isotope ratios. The LADII interface is expected to have broad applicability due to its capability for rapid, precise sample processing and its ability to process extremely limited sample quantities. Studies heretofore hindered by sample size will be open to isotopic investigations. The instrument development will involve three PhD, one MS, and three undergraduate students working in the PI?s laboratory. The semi-automated system will also reduce the person-hours needed for analysis - releasing time for additional scientific directions and efforts. ***