Award Date

12-1-2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Committee Member

Ralf Sudowe

Second Committee Member

Ken Czerwinski

Third Committee Member

Kathleen Robins

Fourth Committee Member

David Hatchett

Fifth Committee Member

Ken Moody

Sixth Committee Member

Ralph Buechler

Number of Pages

85

Abstract

While many methods exist to separate and analyze radionuclides from a variety of environmental matrices, the performance of all of these methods is often limited by other interfering constituents that are consistently found in most of these samples. The presence of such constituents can significantly reduce the recovery of the radioisotopes of interests and lead to incomplete separations.

Strontium has the same oxidation state and a similar atomic radius as calcium and is therefore readily able to substitute for calcium in lattice sites. This similarity in behavior leads to the preferential accumulation of strontium in newly formed bone. The study of radiostrontium uptake and the analysis of bone samples is therefore of great interest for radiation biology, internal dosimetry, and consequence management. The fact that one of the strontium isotopes of greatest biological importance,90Sr, is a pure beta-emitter prevents the use of non-destructive assay techniques and necessitates the development of sophisticated separation methods for radiochemical analysis.

It has been previously reported in the literature that the matrix constituents present in bone can significantly affect the strontium recovery from bone samples1. Bone (hydroxyapatite) is of particular interest when evaluating the effect of common environmental interferences due to the high concentrations of calcium and phosphate present. The goal of this work is to determine the major and minor constituents present in various samples of bone ash and to determine their influence on method performance and strontium recovery. The work presented exploited the use of a variety of radioanalytical separation and isotope detection techniques. Focusing on the characterization of the bone ash, Scanning Electron Microscopy and X-ray Powder Diffraction techniques were used to determine the morphology, to verify the crystalline pattern, and to analyze for any contaminants within each unique bone ash sample. The information obtained helped to determine the elements of interest for batch experiments, which were conducted in order to determine the individual elemental effects that may play a role on the retention of radiostrontium isotopes onto the SR Resin purchased from Eichrom Technologies Inc. The final set of experiments performed were column studies, which focused on the separation of radiostrontium, recovery yields, and the effect of common environmental contaminants on the separation as a whole. Techniques for the detection of radioactive and stable strontium included Liquid Scintillation Counting, Gamma Spectroscopy, and Inductively Coupled Plasma - Atomic Emissions Spectroscopy.

Keywords

90Sr; Bone ash; Bones; Radiochemistry; Radiostrontium; Separation (Technology); Sr-90; Strontium – Isotopes – Separation

Disciplines

Chemistry | Inorganic Chemistry | Radiochemistry

Language

English


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