1984 Volume 33 Issue 9 Pages 465-471
Inductively coupled plasma atomic emission spectrometry (ICP-AES) was applied to the determination of samarium in calcium apatite minerals. The detection limits(S/N=3) of samarium in distilled water and in cyclooctane were 0.66μg/ml and 0.30 μg/ml, respectively. The effect of coexisting elements other than the matrix components on the samarium emission intensity was scarcely observed at 443.43 nm. However, a large amount of calcium phosphate showed high spectral interference and signal suppression. Hence, the separation of samarium from the matrix by solvent extraction was studied with alkanes and cycloalkanes as solvents. Cyclohexane, a more commonly used solvent, was useless in this case, because it extinguished the ICP flame soon after the introduction. The ICP operating conditions with the organic solvents were 2.0 kW R.F. power, 0.481/min carrier gas, 201/min coolant gas, and 1.21/min plasma gas. The experimental results showed that the stability of the ICP flame is higher for higher hydrocarbons. Thus, cyclooctane was used as an extraction solvent in the present work. The apatite minerals(1 g) were dissolved in hot nitric acid, evaporated to dryness, and dissolved in perchloric acid (1011 M, 100 ml). Samarium was then extracted into cyclooctane containing 0.1 M-HDEHP, and determined by ICP-AES. The samarium content in the apatite minerals was found to be (0.261.81)×10-3 %.
