Mesoporous titania nanoparticles with high specific surface area and thermal stable anatasewallwas synthesized from surfactant laurylamine hydrochloride (LAHC) and inorganic precursor Ti(SO4)2. The as-synthesized and calcined materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, transmission electron micrographs, Fourier transform infrared spectroscopy and thermogravimetric analysis. The obtained mesoporous TiO2 nanoparticles have mean diameter of 25.5 nm. The specific surface area of the mesoporous nanosized TiO2 calcined at 400℃ exceeded 189m2 g−1, and that of the samples after calcinations at 500℃ still have 151m2 g−1. The obtained anatase mesoporous TiO2 nanoparticles show relative high thermal stability.

A new analytical procedure for the direct determination of metal impurities (Cr, Cu, Fe and V) in aluminium oxide ceramic powders by slurry sampling fluorination assisted electrothermal vaporization-inductively coupled plasma-atomic emission spectrometry (ETV-ICPAES) is reported. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote the vaporization of impurity elements in aluminium oxide ceramic powders from the graphite tube. A vaporization stage with a long ramp time and a short hold time provided the possibility of temporal analyte-matrix separation. The experimental results indicated that a 10μL1% m/v slurry of aluminium oxide could be destroyed and vaporized completely with 600μg PTFE under the selected conditions. Two aluminium oxide ceramic powder samples were used without any additional pretreatment. Analytical results obtained by using standard addition method with aqueous standard solution were checked by comparison of the results with pneumatic nebulization (PN)-ICP-AES based on the wet-chemical decomposition and analyte-matrix separation. The limits of detection (LODs) between 0.30μg g-1 (Fe ) and 0.08μgg-1 (Cu) were achieved, and, the repeatability of measurements was mainly better than 10%.

A method for the determination of trace amounts of La, Y and Eu, based on the formation of volatile chelates between rare earth elements and 1-phenyl-3-methyl-4-benzoyl-pyrazolone [5] (PMBP) in a graphite furnace, is described. PMBP was used as a chemical modifier for the volatilization of La, Y and Eu from the electrothermal vaporizer into the ICP. The factors affecting the chelating reaction between La, Y and Eu and PMBP were studied in detail, and the vaporization behavior of the chelates formed in the graphite furnace was also investigated. It was found that the presence of an excess of PMBP was necessary to prevent the thermal decomposition of the chelates during the volatilization and transportation processes. Under the optimized conditions, the limits of detection for La, Y and Eu are 8.0, 1.0 and 0.9 ng ml-1, respectively, and the relative standard deviations range from 3.3% (La) to 4.0% (Y). The linear ranges of the calibration graphs span three orders of magnitude. The method was applied to the analysis of an environmental reference material and the results obtained were in good agreement with the reference values.

A method has been developed for the determination of trace impurities in silicon nitride (Si3N4) powders by fluorination assisted electrothermal vaporization (ETV)/ICP-AES using the slurry sampling technique. Polytetrafluoroethylene (PTFE) emulsion as a fluorinating reagent not only effectively destroys the skeleton of Si3N4, but also carries out selective volatilization between the impurity elements (Cu, Cr) and the matrix (Si). The experimental parameters influencing fluorination reactions were optimized. The detection limits for Cu and Cr are 1.05ng/mL (Cu) and 1.58ng/mL (Cr), the RSDs are in the range of 1.9-4.2%. The proposed method has been applied to the determination of Cu and Cr in Si3N4 ceramic powders. The analytical results were compared with those obtained by independent methods.

Titania microtubules with high specific surface areas and well-developed framework mesopores forming the tubular walls by a surfactant-mediated template in the sol-gel process were fabricated in a laurylamine hydrochloride (LAHC)/tetra-n-butyl-orthotitanate (TBOT) system. The outer diameter and the wall thickness of titania microtubules are 2-8 and 0.2-2μm, respectively. The walls of the microtubules consisted of nanochannels with exceptionally uniform pore size. This technique is a convenient and facile procedure for fabricating hierarchical ordered hollow tubules. The possible mechanism of the formation of the microtubules in the present system was discussed in detail.