[Determination of rare earth elements in trialkyl phoshine oxide (TRPO)-kerosene by ICP-AES].

The present paper describes the determination of rare earth elements (REEs) in 30% TRPO-kerosene by inductively coupled plasma atomic emission spectrometry (ICP-AES) with ethanol as diluent. The relative intensities of REEs vary slowly when the content of 30% TRPO-kerosene varies from 4% to 20%. The relative intensity of Ce increased with the contents of H2O increasing from 1% to 7%, but the other REEs did not vary. No effects on the relative intensities of REEs are seen when the concentration of HNCO3 varies from 0.065 to 0.315 mol x L(-1). The effects of Fe and Zr on the relative intensities of REEs are also investigated. The effects of Fe on the relative intensities of REEs are not obvious, but when the concentration of Zr is ten times larger than REEs, the effects are obvious. The method is applicable when the content of 30% TRPO-kerosene ranges from 4% to 20%, the limits of detection of La, Ce, Pr, Nd, Sm are 0.012, 0.040, 0.029, 0.040 and 0.021 microg x mL(-1) respectively, the RSD% is lower than 2%, and the relative error is lower than 3% when compared with the determination result of digestion. In contrast with digestion, this method is simple and rapid, and can accord with the requests of analysis.

[Analytical performance of CID-ICP-AES for alkaline-earth elements].

The plasma spectrometer composed of Charge Injection Device (CID) and echell grating has excellent analytical performance. In the present paper, analytical performance of CID-ICP-AES was studied for alkaline-earth elements. The results showed that the detection limits were 0.00003 mg x L(-1) for Ca, 0.0002 mg x L(-1) for Be, Sr and Ba, and 0.0001 mg x L(-1) for Mg. The self-absorption coefficient was less than 1 for all alkaline earth elements and 0.7-0.8 for Ca and Mg. The linear range of the determination was 10(4)-10(5). The photometric precision was RSD=1% when concentration was less than 1 mg x L(-1).

[Study on enhancing effect of ethanol in lower power ICP].

The effects of ethanol on physical propesties (density, viscosity, surface tension) of sample solution, plasma temperature and electron number density in the ICP were investigated. Detection limits of varying elements in ethanol-water system were determined. The experimental results showed that the gas temperature, excitation temperature and electron number density were lower than those in water solution, the electron temperature and ionization temperature were slightly reduced, while the velocity of aerosol to the plasma increased. The lower detection limits of rare earth elements were observed. The detection limits of other elements were the same as those with water solution. The mechanism of the enhancing effect was discussed.