SREL Reprint #2812

Application of Flow Field Flow Fractionation-ICPMS for the Study of Uranium Binding in Bacterial Cell Suspensions

Brian P. Jackson1, James F. Ranville2, and Andrew L. Neal1,3

1Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina 29802
2Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, Colorado 80401
3Department of Microbiology, University of Georgia, Athens, Georgia 30602

Abstract: Field flow fractionation (FFF) is a size-based separation technique applicable to biomolecules, colloids, and bacteria in solution. When interfaced with ICPMS on-line, elemental data can be collected concurrent with size distribution. We employed hyperlayer flow FFF (FI FFF) methodology to separate cells of Shewanella oneidensis strain MR-1 from exopolymers present in washed cell suspensions. With a channel flow of 4 mL min-1 and a cross-flow of 0.4 mL min-1 cells eluted with a retention time of 4.7 min corresponding to an approximate equivalent spherical cell diameter of 0.8 µm. Cell suspensions were amended with increasing concentrations of U to establish an adsorption isotherm and with fixed U concentrations at varying pH to establish the pH dependence of sorption. A linear sorption isotherm was determined for U solution concentrations of 0.2-16 µM, maximum U sorption occurred at pH 5. A high molecular weight compound, presumably a cell exudate, was identified by FI FFF-ICPMS. This cell exudate complexed U, and at elevated pH, the exudate appeared to have a greater investigations affinity for U than cell surfaces. Thus, FI FFF interfaced with ICPMS detection is a powerful analytical technique for metal sorption studies with bacteria; analysis can be carried out on small sample volumes (25 µL) and additional speciation information can be gained because of the versatile FI FFF separation range and multielement detection capabilities of ICPMS.

SREL Reprint #2812

Jackson, B. P., J. F. Ranville, and A. L. Neal. 2005. Application of flow field flow fractionation-ICPMS for the study of uranium binding in bacterial cell suspensions. Analytical Chemistry 77:1393-1397.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).