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Nanometre-sized alumina was chemically modified with c-mercaptopropyltrimethoxysilane (c-MPTMS). The modified nanometer-sized alumina was characterized by X-ray power diffusion (XRD), X-ray photoelectron energy spectrometer (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) before it was used as solid phase adsorption material for the inductively coupled plasma mass spectrometry (ICP-MS) determination of trace amounts of Hg, Cu, Au and Pd. The effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analytes have been investigated. Under the optimized conditions, the adsorption capacity of modified nanometer-sized Al 2 O 3 was found as 10. 4, 16.3, 15.3, and 17.4 mg g 21 for Hg, Cu, Au and Pd, respectively. The limits of detection were as low as 0.066 and 0.49 ng L 21 for Cu and Hg with a concentration factor of 100 times, and 0.46 and 0.26 ng L 21 for Au and Pd with a concentration factor of 200 times. The developed method has been applied to the determination of trace Hg and Cu in biological and environmental certified materials and Au and Pd in geological certified materials, and the determined values were in a good agreement with the certified values.

A method has been developed for the speciation of trace dissolved Fe(II) and Fe(III) in water by coupling gallic acid (GA) modified nanometer-sized alumina micro-column separation with inductively coupled plasma mass spectrometry (ICP-MS). The separation of Fe(II) and Fe(III) was achieved based on the obvious difference in reaction kinetics between Fe(II) and Fe(III) with GA. Fe(III) was selectively retained on the micro-column at pH 5.5-6.5, while Fe(II) could not be retained by the micro-column at the whole tested pH range of 1.0-6.5, and passed through the micro-column. The Fe(II) can be determined by ICP-MS directly without preconcentration/separation procedure, while Fe(III) retained on the micro-column was then eluted with 1.0 mL of 1 mol L(-1) HCl and determined by ICP-MS. The parameters affecting the separation of Fe(II) and Fe(III) were investigated systematically and the optimum separation conditions were established. Under the optimized conditions, the detection limits of 0.48 microg L(-1) and 0.24 microg L(-1) with relative standard deviation of 5.6% and 4.3%(C= 5 microg L(-1), n= 7) for Fe(II) and Fe(III) were found, respectively. No obvious effect on the speciation of Fe(II) and Fe(III) was found with the change of the ratio of Fe(II) and Fe(III) from 0 ratio 10 to 10 ratio 0. The proposed method was applied for the determination of trace Fe(II) and Fe(III) in environmental water and the recoveries for spiked samples were found to be in the range of 97-105%.

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