Determination of uranium in soil and biological material in Sudan by laser fluorimetry, and comparison with γ spectrometric results for Ra-226

In this work some samples from the area around Miri Lake, a place of high natural radioactivity in Sudan, were analysed by laser fluorimetry for the determination of uranium concentration in soil and biological materials. Gram quantities of samples were ashed. The residue, after fuming with hydrofluoric acid, nitric acid, and perchloric acid, were taken up in a Ca(NO3)2 salting solution, and the uranium was extracted with methylisobutylketone (MIBK). After the stripping of uranium from MIBK solution into 0.001 M HNO3, it was measured with a laser fluorimeter type Scintrex UA-3. At present this technique has not yet been widely used in the field concerned. (orig.)