Metal sulfide clusters in the environment
EMSL Project ID
8217
Abstract
The role of metal clusters in environmental, physical (precipitation, dissolution) and chemical processes (catalysis) is poorly understood. Our research group?s goal is to understand what types of clusters are formed in solution under specified and controlled conditions, within the ranges of pH, ionic strength, etc. that are found in the environment. We are focusing initially on inert metal sulfide clusters, which have recently been found in the environment, and their eventual oxidation, which can release trace metals that may be toxic in the environment. Recent work at the University of Delaware has identified soluble metal sulfide cluster complexes (Fe, Zn, Cu; sizes start at 1 nm or less) and metal oxide clusters (Fe, Mn, Al and Si) as well as nanocrystalline material (aggregates of 2 -20 nm size each) formed via biomineralization in natural systems. These clusters are difficult to detect and analyze because their concentrations are often in the sub-micromolar range.
Mass spectrometry with ionization by electrospray or laser desorption will be used to determine cluster stoichiometry (i.e. elemental composition) in water sampled from the marine environment. A high performance FTMS at EMSL will allow ion accumulation outside the ion cyclotron resonance cell to push detection limits down to the low nanomolar concentration range. We are interested in performing accurate mass measurements of the clusters that are observed, using this information to determine elemental composition, and then performing MS/MS investigations of mass-selected clusters to gain structural information.
Project Details
Start Date
2004-05-24
End Date
2007-03-19
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Lloyd JA, JM Spraggins, MV Johnston, and J Laskin. 2006. "Peptide Ozonolysis: Product Structures and Relative Reactivities for Oxidation of Tyrosine and Histidine Residues ." Journal of the American Society for Mass Spectrometry 17(9):1289-1298.
Spraggins JM, JA Lloyd, MV Johnston, J Laskin, and DP Ridge. 2009. "Fragmentation Mechanisms of Oxidized Peptides Elucidated by SID, RRKM Modeling and Molecular Dynamics." Journal of the American Chemical Society 20(9):1579-1592. doi:10.1016/j.jasms.2009.04.012