Anovel method for inductively coupled plasma atomic emission spectrometry (ICP-AES) determination of trace amounts of Pt (Ⅱ), Pd (Ⅱ) and Rh (Ⅲ), based on gaseous compounds introduction into the plasma as their diethyldithiocarbamate complexes by electrothermal vaporization (ETV), was developed. At the temperature of 1100℃, the trace amounts of Pt, Pd and Rh were vaporized into plasma. The factors affecting the formation of the chelates and their vaporization behaviors, such as ashing temperature and time, vaporization temperature and time, pH and the concentration of chelating reagents were studied in detail. Under the optimized conditions, the limits of detection (LODs) (3σ) of Pt, Pd and Rh for tested solutions were 5.4, 1.4 and 0.8μgml−1, and for actual sample (auto-catalyst NIST SRM 2557) were 0.27, 0.07 and 0.04g g−1, respectively. The relative standard deviations (RSDs) for Pt, Pd and Rh were 1.4, 2.6 and 2.4% (CPt=0.5 gml−1, CPd, Rh=0.25 gml−1, n=7), respectively. The linear ranges of calibration graphs for Pt, Pd and Rh cover three orders of magnitude. Compared with conventional electrothermal vaporization technique, using the reagent of diethyldithiocarbamate as chemical modifier could not only enhance the analytical sensitivities, but also reduce the vaporization temperature. By combination with a separation/preconcentration step, the proposed method had been successfully applied to the analysis of the artificial seawater, tap water and urine with recoveries ranging from 91 to 106%. The two certified reference material meager platinpalladium ore GBW 07293 and auto-catalyst NIST SRM 2557 was also analyzed for validation, and the determined values obtained were in good agreement with the certified values.

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.

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 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.

In this paper, several fluoride chemical modifiers have been tested for electrothermal vaporization-inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) determination of different volatile elements, such as refractory element Ti, medium volatile element Ni and easy volatile element Pb. Reagents tested include polytetrafluoroethylene (PTFE), NH4F, NaF and CuF2•2H2O. The best overall results are obtained using 6% PTFE added to sample. Under the compromise operating conditions, the detection limits of analytes are in the range of 0.8-59μgml 1 and the calibration curves are linear for over three orders of magnitude. The direct determination of Ti, Ni and Pb in GBW 08505 tea leaves reference sample is shown as an example of PTFE chemical modification.