A new method using a micro-column packed with nanometer sized TiO2 as a sorbent has been developed for the on-line preconcentration of trace amounts of rare earth elements (La, Y, Yb, Eu and Dy) prior to their determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). The effects of pH, sample flow rate and volume, elution solution and interfering ions on the separation of analytes have been investigated. The adsorption capacity of nanometer TiO2 for La, Y, Yb, Eu and Dy was found to be 7.0, 6.1, 9.8, 8.3 and 8.8 mg g21, respectively. The method has been successfully applied for the determination of trace rare earth elements in some environmental samples.

A sensitive and simple method for low temperature electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV-ICP-OES) determination of V (Ⅳ) and V (Ⅴ) after separation/preconcentration by a micro-column packed with immobilized thenoyltrifluoroacetone (TTA) on microcrystalline naphthalene has been developed. Thenoyltrifluoroacetone was used as both a chelating agent for micro-column separation/preconcentration and a chemical modifier for ETV-ICP-OES determination of vanadium. Both vanadium species could be trapped by micro-column at pH 4.0, and the vanadate (VO2+) ion could be collected selectively at pH 2.4. Solid material loaded with analyte in the micro-column was dissolved with 100 AL of acetone containing 2.0 mmol L1 TTA and the vanadium was determined subsequently by ETV-ICP-OES. The concentration of vanadyl (VO2+) ion was calculated by subtracting the vanadate concentration from the total concentration of vanadium. Under the optimized experimental conditions, the detection limit (3r) for the preconcentration of 5mL of aqueous solution is 0.068 Ag L1 for both species and the relative standard deviations were 4.3% for vanadium (Ⅴ) and 4.8% for vanadium (Ⅵ) (c=10 Ag L1, n=7), respectively. The method was applied successfully to the determination of vanadium (Ⅳ) and vanadium (Ⅴ) in natural water samples.

A method of electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace lanthanides and yttrium in soil samples with a polytetrafluorethylene (PTFE) emulsion as chemical modifier to promote the vaporization of the analytes from the graphite furnace was developed in this paper. The analytical characteristics, spectral interference and matrix effect of the analytical method were evaluated and critically compared with those of pneumatic nebulization inductively coupled plasma mass spectrometry (PN-ICP-MS). Under the optimized operation conditions, the relative detection limits of lanthanides (La-Lu) and yttrium for ETV-ICP-MS and PN-ICP-MS were 0.4-20ngl−1 and 1.0-21ngl−1, respectively, the absolute detection limits for ETV-ICP-MS were 4-200 fg, which were improved by 1-2 orders of magnitude compared with PN-ICP-MS. While the analytical precision of ETV-ICP-MS is worse than that of PN-ICP-MS, with the R. S. D. S (%) of 4.1-10% for the former and 2.9-7.8% for the latter. Regarding to the matrix effect, both conventional method and stepwise dilution method were employed to observe the effect of matrix and the very similar results were obtained. It was found that the highest tolerance concentration of the matrix is 1000mgl−1 and 800mgl−1 for ETV-ICP-MS and PN-ICP-MS, respectively. To assess the accuracy, the proposed method was applied to the determination of trace lanthanides and yttrium in three different soil standard reference materials and one soil sample, and the determined values are in good agreement with the certified values or reference values.

A method is proposed to determine trace rare earth impurities in high-purity CeO2 by HPLC combined with electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES). The chromatographic retention behaviours of the matrix (Ce) and rare earth impurities were studied using 2-ethylhexyl hydrogen 2-ethylhexylphosphonate (P507) resin as the stationary phase and dilute nitric acid as the mobile phase. It was found that the matrix (Ce) can be separated quantitatively with dilute nitric acid as the mobile phase, and the rare earth impurities (Pr

A low temperature electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) method for the determination of palladium, by using sample introduction of gaseous palladium oxinate, was developed. The thermally stable palladium oxinate was formed and vaporized at a temperature of 900℃ from the graphite furnace. The main factors affecting the vaporization behavior of the analyte were investigated in detail. The detection limit of palladium for this method was 50pg, and the relative standard deviation (RSD) for 0.2μgml-1 palladium was 4.7% (n=8). Compared with conventional ETV-ICPAES, the analytical sensitivity of this method was improved by one order of magnitude. The proposed method was applied to the determination of trace palladium in geological samples with satisfactory results.