Zucheng Jiang

Nanometer-size titanium dioxide microcolumn on-line preconcentration of trace metals and their determination by inductively coupled plasma atomic emission spectrometry in water

Abstract A new method using a microcolumn packed with nanometer TiO 2 as solid-phase extractant has been developed for the simultaneous preconcentration of trace amounts of Cu, Mn, Cr and Ni prior to their measurements by inductively coupled plasma atomic emission spectrometry (ICP-AES). Effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analytes have been investigated. The adsorption capacity of nanometer TiO 2 was found as 0.108, 0.149, 0.039 and 0.034xa0mmolxa0g −1 for Cu, Cr, Mn and Ni, respectively. The separation of analytes can be achieved from water samples with a concentration factor of 50 times. The method has been applied for the determination of trace elements in biological sample and lake water with satisfactory results.

Preconcentration of lanthanum, europium and ytterbium with tribromoarsenazo–cetylpyridinium bromide supported on microcrystalline naphthalene and their determinations by inductively coupled plasma atomic emission spectrometry

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 3 moll(-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 La(3+), Eu(3+) and Yb(3+) were 1.3-8.6 ngml(-1), and the relative standard deviations obtained for nine replicate determinations at a concentration of 0.5 mugml(-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.

Fluorination and volatilization of refractory elements from a graphite furnace for sample introduction into an inductively coupled plasma by using a polytetrafluoroethylene slurry

A method was developed to determine refractory elements by inductively coupled plasma atomic emission spectrometry (ICP-AES) with sample introduction by electrothermal vaporization. A slurry of polytetrafluoroethylene was used to form fluorides rather than carbides of the elements. In this way, the refractory elements were efficiently vaporized and subsequently introduced into the plasma. The detection limits for Zr, V, Cr, W, Mo, B and Ti were improved by a factor of 7–119, compared with those of electrothermal vaporization ICP-AES without the fluorinating agent. No memory effects were observed and adequate precision was obtained. The fluorination process is also discussed.