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Barium is one of those less ubiquitous but potentially harmful contaminants in the environment. Its presence in the environment has been demonstrated. However, securing reliable information about its concentration is hampered by lack of a sensitive, simple, accurate method of analysis. The methods of determination of trace concentrations of barium have been reviewed.

This present work presents a simple, selective, sensitive method for the determination of barium in aqueous systems. The method combines the solvent extraction of the barium hexafluoro acetylacetonate into isoamyl acetate with atomic absorption determination of barium. This combination of methods increases the sensitivity of the barium determination by two orders of magnitude from 0.3 µg/ml to 0.005 µg/ml % as measured from the concentration" in the aqueous phase. It also presents a quick method of determining barium at concentrations as low as O.OI5 µg/ml; this is within the range found in natural waters.

Attempts to remove or mask sodium or potassium were unsuccessful. It was found necessary to use a concentration of 1,000 µg/ml of potassium in the aqueous phase. The potassium extracted into the organic phase and acted as an ionization buffer in the absorption of barium. Sodium was shown to have no further buffering effect.

The absorption of barium was shown to be a direct function of the extraction of potassium which is dependent upon pH. The calibration curve showed linearity from 0.0I5 µg/ml to 1.0 µg/ml. This method can tolerate Be2+, Mg2+, Al3+and Co2+ at the hundred-fold level. Among the other common ions tested only Cr3+ and Mn2+ gave significant interference at the thousand-fold level. Tartrate was used to mask the Pb2+ interference and Fe3+ was masked with diethyldithio carbamate.