Barium and Strontium Determination in Biological Materials by Atomic Absorption Spectroscopy

Abstract

Ashed samples of diet, excreta, soft tissue, and bone were measured for trace amounts of stable barium and strontium by atomic absorption spectroscopy after classical chemical separation and anion exchange chromatography. Barium, strontium, and calcium were separated from silica by dehydration, the alkali metals by phosphate collection, and magnesium, the transition metals, and phosphate by nitrate precipitation. Barium was separated from strontium and calcium by absorption on Bio-Rad AG 1-X8 (100–200 mesh) anion exchange resin in methanol—nitric acid mixed solvent. Barium-133 and strontium-85 tracers were added to the samples to correct radio-metrically for losses during the chemical method. Atomic absorption measurements for barium and strontium were made at the resonance lines of 5536 and 4607 Å, with nitrous oxide—acetylene and air—acetylene flames, respectively. Radiometric yields of barium-133 and strontium-85 ranged between 85%–95% and 75%–99%, respectively, with an average coefficient of variation of 5%–6%.