Application of Flow Field Flow Fractionation-ICPMS for the Study of Uranium Binding in Bacterial Cell Suspensions
Brian P. .Jackson,1 James F. Ranville,2 and Andrew
L. Neal1,3
1Savannah River Ecology Laboratory, University of Georgia,
Aiken, South Carolina 29802
2 Department of Chemistry and Geochemistry, Colorado School
of Mines, Golden, Colorado 80401, and
3 Department of Microbiology, University of Georgia, Athens,
Georgia 30602
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 multielementm
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.
