[en] Atomic absorption spectrophotometry (AAS) employing electrothermal atomization in a pyrolytic graphite tube is shown to be a precise and accurate method for analysis of 11 rare earth, or rare-earth-like elements in air filter samples taken in a thorium and rare earth refinery. The method is fairly rapid since it involves only fluoric acids. Each element was sequentially analyzed from the same resulting solution by using either the techniques of standard-curve calibration or that of standard additions. The two methods used on the same sample gave essentially identical results (composite ratio for 171 such trials being 0.9996). Matrix effects were negligible and no background correction was necessary. The average percent standard deviation for all duplicate trials (176) was 4.2%. Elements analyzed by this method were La, Nd, Sm, Eu, Gd, Dy, Ho, Tm, Yb, Gd, Sc and Y. Other rare earths such as erbium (Er), lutetium (Lu), and terbium (Tb), with comparable analytical sensitivity by AAS to Dy, Sm, and Nd, respectively, could presumably be analyzed by this method as well

[en] An analytical method utilizing x-ray fluorescence (XRF) spectrometry is described to determine simultaneously the amounts of lanthanum, cerium, praseodymium, and neodymium in air-filter samples collected at a rare-earth processing refinery in Illinois

[en] The determination of Sc and seven rare earth elements, Nd, Sm, Dy, Ho, Eu, Tm, and Yb, in biological samplesby atomic absorption spectrophotometric analysis (AAS) using electrothermal atomization in a pyrolytic graphite tube is shown to be rapid, precise and accurate. The technique utilizes the method of standard additions and linear regression analysis to determine results from peak area data. Inter-elemental interferences are negligible. The elements found sensitive enough for this type of analysis are, in order of decreasing sensitivity, Yb, Eu, Tm, Dy, Sc, Ho, Sm and Nd. The determination in these types of materials of Gd and elements less sensitive to AAS detection than Gd does not appear to be feasible. Results are presented on the concentrations of these elements in 41 samples from human subjects, cows and vegetables with normal environmental exposure to the rare earth elements. The composite percent mean deviation in peak-area readings for all samples and all elements examined was 4%. The mean standard error in the results among samples was about 6.5%

[en] An analytical method for the determination of four lanthanides in air filter samples is described. The method involves simultaneous quantitative determinations of La, Ce, Pr, and Nd at the microgram level by x-ray fluorescence spectrometry without chemical separation of these rare earths and without serious interferences from the dust matrices on the filters. The method has been used successfully to analyze some air filter samples collected at a rare earth processing refinery in Illinois. A description of the development of the method is given as well as the results obtained by using this method on the air filter samples. The reproducibility of the results was generally +-5%

[en] This investigation has resulted in an analytical method for the quantitative determination of total lanthanide concentration in aqueous solution by absorbance at 240 nm followed by quantitative determination of individual lanthanide ion concentrations by the use of concentration-responsive absorption peaks in the 190-235 nm region. The 240-nm peak is present and is proportional to concentration regardless of the ligand employed to complex the lanthanides (including H₂O). The individual lanthanide/ligand peaks in the 190-235 nm region were selected on the basis of their separation from one another, their linearity of absorbance vs. concentration, and their statistical reliability based on replicate sample analyses. Lanthanides involved in this investigation were La⁺³, Nd⁺³, Eu⁺³, Ho⁺³, and Yb⁺³. Ligands ultimately selected for complexation were citrate for La⁺³, Nd⁺³, Nd⁺³, and Ho⁺³, and DTPA for Eu⁺³, Ho⁺³, and Yb⁺³. When large amounts of heavy metal ions were present, a modified method was developed with citrate as the only complexing ligand for all five lanthanides. The method here developed permits the analyses of lanthanide ions in aqueous solution without prior separation and involves the use of comparatively inexpensive instrumentation (UV absorption spectrophotometer). 12 refs., 5 figs., 15 tabs