Rui Liu

Publications (8)28.07 Total impact

• Article: Determination of trace rare earth elements by inductively coupled plasma optical emission spectrometry after preconcentration with immobilized nanometer titanium dioxide

  Pei Liang, Jing Cao, Rui Liu, Yan Liu
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  ABSTRACT: Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer TiO2) was prepared by the sol-gel method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adsorptive potential of immobilized nanometer TiO2 for rare earth elements (REEs) was assessed in this work. The REE ions can be quantitatively retained by immobilized nanometer TiO2 at a pH range of 6–9, and 0.5 mol L−1 HNO3 was sufficient for complete elution. A method has been developed for the determination of trace REEs based on preconcentration with a microcolumn packed with immobilized nanometer TiO2 and determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The material showed relatively high chemical stability towards the action of acidic solutions. The packed microcolumn used in proposed procedure did not show any over pressure or swelling and can be used up to at least 20 adsorption-elution cycles without decrease in the performance. The optimum experimental parameters for preconcentration of REEs, such as pH of the sample, sample flow rate and volume, elution solution and interfering ions, have been investigated. The detection limits for REEs was between 3 and 57 ng L−1, and the relative standard deviations (RSDs) for the determination of REEs at 10 ng mL−1 level were found to be less than 6% when processing 100 mL sample solution. The method has been successfully applied to the determination of trace REEs in some environmental samples.
  Microchimica Acta 04/2012; 159(1):35-40. · 3.03 Impact Factor
• Article: Determination of Platinum and Palladium in Geological Samples by Inductively Coupled Plasma‐Atomic Emission Spectrometry after Preconcentration with Immobilised Nanometric Titanium Dioxide

  Pei Liang, Ehong Zhao, Rui Liu
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  ABSTRACT: A new method has been developed for the determination of platinum and palladium based on separation and preconcentration with a microcolumn packed with nanometric TiO2 immobilised on silica gel (immobilised nanometric TiO2) prior to their determination by inductively coupled plasma-atomic emission spectrometry. The optimum experimental parameters for the preconcentration of Pt and Pd, such as the pH of the sample solution, its flow rate and volume, the type and concentration of eluent and interfering ions, have been investigated. Platinum and Pd could be quantitatively retained by immobilised nanometric TiO2 in the pH range 6–8, then eluted completely with 2.0 ml of 3% m/v thiourea in 1.0 mol l−1 HNO3. The detection limits of this method for Pt and Pd were 12 and 7. 6 ng l−1 with an enrichment factor of 100, and the relative standard deviations were 4.7% and 3.3% at the 10 ng ml−1 level. The method has been applied for the determination of Pt and Pd in geological samples with satisfactory results.Une nouvelle méthode de détermination du platine et du palladium a été développée, sur la base d'une séparation et une pré-concentration sur une micro-colonne remplie de TiO2 nanométrique, fixé sur du silica gel (TiO2 nanométrique immobilisé), suivies d'une analyse par spectrométrie d'émission couplée à une source de plasma induit. Les paramètres expérimentaux optimaux de la pré-concentration de Pt et Pd, tels que le pH de la solution, la vitesse découlement et le volume, le type et la concentration de l'éluant, ainsi que les ions interférents, ont été testés. Pt et Pd peuvent être retenus quantitativement par le TiO2 nanométrique immobilisé pour des valeurs de pH entre 6 et 8, puis élués complètement avec 2 ml d'une solution de thiourée à 3% m/v dans HNO3à 1 mol l−1. Les limites de détection de cette méthode pour Pt et Pd sont de 12 et 7. 6 ng l−1 avec un facteur d'enrichissement de 100, et les déviations standard relatives étaient de 4.7% et 3.3% pour des concentrations de l'ordre de 10 ng ml−1. La méthode a été appliquée à la détermination de Pt et Pd dans des échantillons géologiques et a donné des résultats satisfaisants.
  Geostandards and Geoanalytical Research 02/2009; 33(1):63 - 69. · 2.00 Impact Factor
• Article: Determination of trace molybdenum in biological and water samples by graphite furnace atomic absorption spectrometry after separation and preconcentration on immobilized titanium dioxide nanoparticles

  Pei Liang, Qian Li, Rui Liu
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  ABSTRACT: A new method has been developed for the determination of trace molybdenum based on separation and preconcentration with TiO2 nanoparticles immobilized on silica gel (immobilized TiO2 nanoparticles) prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS). The optimum experimental parameters for preconcentration of molybdenum, such as pH of the sample, sample flow rate and volume, eluent and interfering ions, have been investigated. Molybdenum can be quantitatively retained by immobilized TiO2 nanoparticles at pH 1.0 and separated from the metal cations in the solution, then eluted completely with 0.5mol L−1 NaOH. The detection limit of this method for Mo was 0.6ng L−1 with an enrichment factor of 100, and the relative standard deviation (RSD) was 3.4% at the 10ng mL−1 Mo level. The method has been applied to the determination of trace amounts of Mo in biological and water samples with satisfactory results.
  Microchimica Acta 12/2008; 164(1):119-124. · 3.03 Impact Factor
• Article: Determination of trace lead in water samples by continuous flow microextraction combined with graphite furnace atomic absorption spectrometry.

  Jing Cao, Pei Liang, Rui Liu
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  ABSTRACT: A new method of continuous flow microextraction (CFME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was proposed for the determination of trace lead in water samples. A drop of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) dissolved in benzene is injected into a glass chamber by a microsyringe and held at the outlet tip of a PTFE connecting tube, the sample solution flows right through the tube and the glass chamber, the solvent drop interacts continuously with the sample solution, and the analyte was extracted into the drop and concentrated. After extracting for a period of time, the drop was retracted into the microsyringe and directly injected into graphite furnace for determination of Pb. Several factors affecting the extraction efficiency, such as solution pH, sample flow rate, drop volume and extraction time, were optimized. Under the optimized conditions, a concentration factor of 45 was achieved, and the detection limits for Pb were 12 pg mL(-1). The relative standard deviation for six replicate analyses of 10 ng mL(-1) Pb was 6.8%. The proposed method was applied to determine of trace Pb in water samples with satisfactory results.
  Journal of Hazardous Materials 05/2008; 152(3):910-4. · 4.17 Impact Factor
• Article: Determination of trace lead in water samples by graphite furnace atomic absorption spectrometry after preconcentration with nanometer titanium dioxide immobilized on silica gel.

  Rui Liu, Pei Liang
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  ABSTRACT: Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer TiO2) was prepared by sol-gel method and characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The adsorptive capability of immobilized nanometer TiO2 for lead was assessed in this work using column method. It was found that lead can be quantitatively retained by immobilized nanometer TiO2 in the pH range 4-7, then eluted completely with 1.0molL(-1) HCl. The adsorption capacity of immobilized nanometer TiO2 for Pb was found to be 3.16mgg(-1). A new method has been developed for the determination of trace lead based on preconcentration with a microcolumn packed with immobilized nanometer TiO2 prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS). The detection limit of this method for Pb was 9.5ngL(-1) with an enrichment factor of 50, and the relative standard deviations (R.S.D.s) was 3.2% at the 10ngmL(-1) Pb level. The method was validated using a certified reference material, and was applied for the determination of trace lead in water samples.
  Journal of Hazardous Materials 04/2008; 152(1):166-71. · 4.17 Impact Factor
• Article: Determination of gold by nanometer titanium dioxide immobilized on silica gel packed microcolumn and flame atomic absorption spectrometry in geological and water samples.

  Rui Liu, Pei Liang
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  ABSTRACT: A new method has been developed for the determination of gold based on separation and preconcentration with a microcolumn packed with nanometer TiO2 immobilized on silica gel (immobilized nanometer TiO2) prior to its determination by flame atomic absorption spectrometry. The optimum experimental parameters for preconcentration of gold, such as pH of the sample, sample flow rate and volume, eluent and interfering ions, have been investigated. Gold could be quantitatively retained by immobilized nanometer TiO2 in the pH range of 8-10, then eluted completely with 0.1 mol L(-1) HNO3. The detection limit of this method for Au was 0.21 ng mL(-1) with an enrichment factor of 50, and the relative standard deviation (R.S.D.) was 1.8% at the 100 ng mL(-1) Au level. The method has been applied for the determination of trace amounts of Au in geological and water samples with satisfactory results.
  Analytica chimica acta 01/2008; 604(2):114-8. · 4.31 Impact Factor
• Article: Single drop microextraction combined with graphite furnace atomic absorption spectrometry for determination of lead in biological samples

  Pei Liang, Rui Liu, Jing Cao
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  ABSTRACT: Single drop microextraction combined with graphite furnace atomic absorption spectrometry is introduced for the determination of trace lead in water samples. A drop of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) dissolved in benzene was held at the tip of a microsyringe and immerged into the sample solution which was stirred, the solvent drop interacts with the sample solution, and the analyte was extracted into the drop and concentrated. After extracting for a period of time, the drop was retracted into the microsyringe and directly injected into graphite furnace for GFAAS determination of Pb. Several factors affecting the extraction efficiency, such as pH of sample solution, drop volume, stirring rate and extraction time, were optimized. Under the optimized conditions, an enhancement factor of 16 was achieved, and the detection limits for Pb were 25 ng L−1. The relative standard deviation for seven replicate determination of 10 ng mL−1 Pb was 6.1%. The method was applied to determine trace Pb in biological samples with satisfactory results.
  Microchimica Acta 12/2007; 160(1):135-139. · 3.03 Impact Factor
• Article: Speciation analysis of inorganic arsenic in water samples by immobilized nanometer titanium dioxide separation and graphite furnace atomic absorption spectrometric determination.

  Pei Liang, Rui Liu
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  ABSTRACT: A novel solid phase extraction sorbent, nanometer titanium dioxide immobilized on silica gel (immobilized nanometer TiO2), was prepared by sol-gel method, and the adsorptive potential of immobilized nanometer TiO2 for inorganic arsenic species (As(III) and As(V)) was assessed. It was found that both As (III) and As(V) could be adsorbed quantitatively on immobilized TiO2 within a pH range of 5.0-7.5, and only As(III) could be quantitatively retained on the sorbent within a pH range of 9.5-10.5 while As(V) was passed through the microcolumn without the retention. Based on this fact, a new speciation scheme for inorganic arsenic was established, which involved determining total As at pH 6.0 and As(III) at pH 10, with As(V) obtained by difference. The adsorption capacity of immobilized nanometer TiO2 for As(III) was found to be 4.22 mg g(-1). Under the optimized conditions, the detection limits of this method for As(III) were 24 ng L(-1) with an enrichment factor of 50, and the relative standard deviation (R.S.D.%) was 4.8% (n=11, c=5 ng mL(-1)). The proposed method has been applied to the speciation of inorganic arsenic in natural water samples with satisfactory results.
  Analytica chimica acta 11/2007; 602(1):32-6. · 4.31 Impact Factor