A sensitive and rapid method for the determination of lanthanum, europium and ytterbium by inductively coupled plasma atomic emission spectrometry (ICP-AES) after solid-liquid extraction with microcrystalline naphthalene was developed. Analytes could be quantitatively adsorbed on tribromoarsenazo-cetylpyridinium bromide-naphthalene (TBA-CPB-naphthalene) packed in a column and determined by ICP-AES after desorption with 3mol l−1 HCl. The effect of various experimental parameters, such as pH, reagent amounts, naphthalene concentrations and diverse ions, on the determination of interesting elements were investigated in detail. Under the optimized experimental conditions, the detection limits of this method for La3+, Eu3+ and Yb3+ were 1.3-8.6ng ml−1, and the relative standard deviations obtained for nine replicate determinations at a concentration of 0.5gml−1 were 1.4-2.2%. The proposed method has been applied in the analysis of NIES CRM No.8 vehicle exhaust particulates and GBW 07602 GSV-1 bush branches and leaves for La, Eu and Yb, and La in NIST SRM 1752 citrus leaves samples; the analytical results were in good agreement with reference values.

A simple and selective method of flow injection (FI) using a micro-column packed with chelating resin YPA4 as solid phase extractant was developed for the preconcentration and separation of trace amount of noble metals, Au (Ⅲ), Ag (Ⅰ), Pd (Ⅱ) and Pt (Ⅳ), followed by ICP-AES determination. In HNO3 media, the chelating resin was selective towards Au(Ⅲ), Ag (Ⅰ), Pd (Ⅱ) and Pt (Ⅳ), and the analysed ions were readily desorbed quantitatively with 5ml of 2.5%m/v thiourea. Effects of acidity, sample flow rate and concentration, elution solution and interfering ions on the recovery of the analytes were systematically investigated. Under optimum conditions, the adsorption capacities of YPA4 for Au (Ⅲ), Ag (Ⅰ), Pd (Ⅱ) and Pt (Ⅳ) were 67.2, 43.1, 64.8 and 27.6mg per gram of resin in HNO3 media, respectively. It was found that YPA4 could be used for more than eight runs in HNO3 media without loss of capacity. The proposed method was used for the determination of trace noble metals in geological and environmental samples, and theanalytical results obtained were in good agreement with the recommended values.

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 method of glow discharge atomic emission spectroscopy (GD-AES) is described for the determination of rare earth elements (REEs) after separation and preconcentration by micro-column packed with immobilized 1-phenyl-3-methyl-4-benzoyl-5-pyrazone (PMBP) on icrocrystalline naphthalene. The graphite electrode with solution residue on its surface was used as a cathode. Various factors (the form of cathode, working condition) influencing the determination of the analytes were studied in detail. Under the experimental conditions selected, the detection limits for the determination of La, Nd, Eu, Dy and Y are 0.24, 0.32, 0.01, 0.07 and 0.06mg/mL, respectively, with relative standard deviations (RSDs) in the range of 5-10%. The method was applied to determine La, Nd, Eu, Dy and Y in geological samples, and the analytical results are in good agreement with the 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.