Rare earth elements mass spectrum

Figure 6.6 Mass spectrum of rare earth elements tREEs) measured by CE-ICP-MS with on line separation of analytes (50 nl solution volume) a) natural isotopic pattern, concentration of each REE - 800ngg b) in an irradiated tantalum target (). S. Becker and H. ]. Dietze, Int. /. Mass Spectrom. Ion Proc. 197, 1-35 (2000). Reproduced by permission of the Royal Society of Chemistry.)...

Usually, atomic mass spectra are considerably simpler and easier to interpret than optical emission spectra. This property is particularly important for samples that contain rare earth elements and other heavy metals. such as iron, that yield complex emission spectra. Figure 11-15b illustrates this advantage. This spectral simplicity is further illustrated in Figure 11-16. which is the atontic mass spectrum for a mixture of fourteen rare earth elements that range in atomic mass number from 1.39 to 175. T he optical emission spectrum for such a mixture would be so complex that interpretation would be tedious, time-consuming, and perhaps impo.ssible. 

Figure 139 Mass spectrum of univalent rare earth ions. The concentration of each rare earth element is 15mgl . (Adapted from A. L. Gray and A. R. Date, Analyst (London), 1983, 108, 1033)...

Many attempts were made historically to solve the problems of interferences affecting rare earth element (REE) ion signals [10,11]. Spectral stripping or deconvolution of the mass spectrum, combined with moderate energy filtering, have been so far the most common SIMS procedure for REE analysis in geological materials (e.g.. References [12,13]). In recent years at CNR-... 

Figure 1 Glow discharge mass spectrometry (GD-MS) spectrum of a mixture of rare earth oxides compacted in a tantalum host matrix. Oxide composition 5% by weight in disk, each element present at 110 ppm. (From Ref. 39.)...

These characteristics are illustrated in the mass spectrum shown in Fig. 5.3. Lanthanum at 1 mg 1 yields nearly 10 counts s , which is near the upper end of the linear range of the detector. Peaks are observed for La " " and LaO+, but they are small relative to La". The low abundance of LaO" shows that even refractory rare earth oxides are dissociated efficiently (but not H completely). Most elements yield much lower levels of M or MO than shown for La in Fig. 5.3. The two isotope peaks for Eu illustrate the isotopic capability of the technique. Finally, the total signal for the two isotopes of Eu is comparable to the signal for La" because these two elements are ionized to nearly the same extent in the ICP and because they are extracted and detected with similar efficiency. 

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