Determination of Rare Earths

SPECTROPHOTOMETRIC DETERMINATION OF RARE EARTH ELEMENTS IN MONO CRYSTALS AND STARTING LEAD MOLYBDATE RAW MATERIAL... 

Itoh, A., Hamanaka, T., Rong, W., Ikeda, K., Sawatari, H., Chiba, K., and Haraguchi, H., Multielement determination of rare earth elements in geochemical samples by liquid chromatography/inductively coupled plasma mass spectrometry, Anal. Sci., 15, 17, 1999. 

Kutun, S. and Akseli, A., New elution agent, sodium trimetaphosphate, for the separation and determination of rare earths by anion-exchange chromatography, /. Chromatogr. A, 847, 261, 1999. 

Leddicotte, G. W. (1956). Some methods for determination of rare earth elements, page 63 in Rare Earths in Biochemical and Medical Research ... 

The chemistry of rare earth elements makes them particularly useful in studies of marine geochemistry [637]. But the determination of rare earths in seawater at ultratrace levels has always been a difficult task. Of the various methods applied, instrumental neutron activation analysis and isotope dilution mass spectrometry were the main techniques used for the determination of rare earths in seawater. However, sample preparation is tedious and large amounts of water are required in neutron activation analysis. In addition, the method can only offer relatively low sample throughputs and some rare earths cannot be determined. The main drawbacks of isotopic dilution mass spectrometry are that it is time-consuming and expensive, and monoisotopic elements cannot be determined as well. 

At present, inductively coupled plasma mass spectrometry provides a unique, powerful alternative for the determination of rare earths in natural samples [638,639]. Nevertheless, its application to the determination of rare earths at ultratrace concentration level in seawater is limited, because highly saline samples can cause both spectral interferences and matrix effects [640]. Therefore, a separation of the matrix components and preconcentration of the analytes are prerequisites. To achieve this goal, many preconcentration techniques have been used, including coprecipitation with... 

Casetta, B., Giaretta, A., and Mezzacasa, G. (1990). Determination of rare earth and other trace elements in rock samples by ICP-mass spectrometry comparison with other techniques. Atomic Spectroscopy 11 222-228. 

Dulski, P. (1994). Interferences of oxide, hydroxide and chloride analyte species in the determination of rare earth elements in geological samples by inductively coupled plasma-mass spectrometry. Fresenius Journal of Analytical Chemistry 350 194-203. 

Table 9.31 Determination of rare earth elements in Precambrian zircon and monazite from Baltic Shield by SSMS (concentration in Pgg-1,)36.

S. Augagneur, B. Medina, J. Szpunar, R. Lobinski, Determination of rare earth elements in wine by inductively coupled plasma mass spectrometry using a microcon-centric nebulizer, J. Anal. Atom Spectrom., 11 (1996), 713-721. 

Operating parameters in the determination of rare-earth elements with the IL555 flameless atomizer [186]. 

The operating parameters and the isotopes used in this technique are given in Tables 1.55 and 1.56. Correlation plots obtained by this technique in the determination of rare earths are given in Figs 1.20 and 1.21. 

In principle, the applications of ICP-MS resemble those listed for OES. This technique however is required for samples containing sub-part per billion concentrations of elements. Quantitative information of nonmetals such as P, S, I, B, Br can be obtained. Since atomic mass spectra are much simpler and easier to interpret compared to optical emission spectra, ICP-MS affords superior resolution in the determination of rare earth elements. It is widely used for the control of high-purity materials in semiconductor and electronics industries. The applications also cover the analysis of clinical samples, the use of stable isotopes for metabolic studies, and the determination of radioactive and transuranic elements. In addition to outstanding analytical features for one or a few elements, this technique provides quantitative information on more than 70 elements present from low part-per-trillion to part-per-million concentration range in a single run and within less than 3 min (after sample preparation and calibration). Comprehensive reviews on ICP-MS applications in total element determinations are available. " ... 

Meisel, T. (2000) Determination of rare earth elements (REE) in geological samples by sodium peroxide sintering and ICP-MS detection Agilent Technologies, ICP... 

A tandem system consisting of pulsed dye laser ablation and ionization in a GD source for MS have been described by Barshick and Harrison [649]. The role played by the working gas (Ar, He, Ne) on redeposition of sputtered material has also been clarified. Removal of interfering species in GD-MS is possible through the use of getters such as Ag, C, Ta, Ti and W [650]. This approach has been applied successfully in the determination of rare earths so as to avoid oxide ion formation. 

Broekaert J. A. C., Leis F. and Laqua K. (1979) Application of an inductively coupled plasma to the emission spectroscopic determination of rare earths in mineralogical samples, Spectrochim Acta, Part B 34 73-84. 

Dittrich K., Berndt H., Broekaert J. A. C., Schaldach G. and Tolg G. (1988) Comparative study of injection into a pneumatic nebuliser and tungsten coil electrothermal vaporisation for the determination of rare earth elements by inductively coupled plasma optical emission spectrometry, J Anal At Spectrom 3 1105—1110. 

Determination of rare earth elements in geological samples by ICP source mass spectrometry, J Anal At Spectrom 2 269-281. 

Arsenazo I and a number of its analogues are derivatives of chromotropic acid (1,8-dihydroxynaphthalene-3,6-disulphonic acid). Arsenazo I is applied to the determination of rare earths, Th, U, Zr, Ti, Nb, and other metals. 

K. Yoshida and H. Haragacfai, Determination of rare earth elements by liquid chromatography/ inductively coupled plasma atomic emission. Anal Chem., 56,1984. 

Although dry ashing at 450-900°C is used for plant materials (Kabata-Pendias and Dudka, 1990, 1991 Cresser et al., 1992) this approach is not recommended unless special precautions are taken. Even then many volatile elements of interest (Pb, Cd, As etc.) may be lost. For the determination of rare earth and other non-volatile elements however it may be a successful procedure before acid treatment. 

Among the determined elements dominate are the alkaline earth elements and alkali metals (K, Ca, Rb, Sr) and the transition metals Mn, Fe, Cu, Zn etc. The reliable determination of some ecologically important elements like Hg, Se, As, Sb has not been proven. Obviously the determination of rare earth elements, platinum metals and heavy elements is a problem although theoretically XRF is a good method for their analysis. Values for La and Nb by TXRF have been reported in standard reference materials only in Market (1996). 

Robinson P., Higgins N.C. and Jenner J.G., 1986, Determination of rare earth element, yttrium and scandium in rocks by an ion-exchange X-ray fluorescence technique. Ckem. GeoL, 55, 121-137. 

The presence of U interferes with the determination of rare earths. This element is fissioned on neutron bombardment and produces Ce, La, Nd and Sm nuclides as a result, these REE may be incorrectly identified as present in a sample. 

Table 4. Analytical lines (nm) suitable for the determination of rare earths in advanced ceramic materials...

R. Tertian, A rapid and accurate x-ray determination of rare earth elements in solid solution on liquid materials using the double-dilution method, Adv. X-ray Anal, 72 546(1969). 

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