电感耦合等离子体-质谱法测定内墙漆中8种重金属杂质

文章建立了用电感耦合等离子体-质谱(ICP-MS)法测定内墙漆中Se、Cd、Sb、Cr、Pb、Hg、As、Ba等8种重金属含量的方法。样品经过预处理用盐酸溶解,得到样品溶液后用电感耦合等离子体质谱进行测定。8种重金属杂质元素的方法检出限为0.02-0.5ng/g。利用建立的方法,对市场上某种墙面漆中的8种金属元素进行测定,并进行了加标回收实验,加标回收率为94%-106%。各杂质元素均为10 ng/mL的混合标准溶液平行7次进样的相对标准偏差均小于5%。该方法操作简便,能够满足内墙漆中有害重金属杂质测定的需要。     

Determination of metals in plant samples by using a sector field inductively coupled plasma mass spectrometer

The capability of pine needles to be used as bioindicators of trace metals in the environment is discussed. Samples were collected around the Instituto de Pesquisas Energéticas e Nucleares, the largest nuclear research center in South America and chosen to be the sampling target area. Results obtained for the elemental content of Th and U in samples collected nearby an uranium facility were, respectively, 0.072 and 0.042 mg kg(-1), while the results obtained for the La, Ce and Sm content in a sample collected in the vicinity of an extraction laboratory were, respectively, 0.22, 0.88 and 0.39 mg kg(-1). All these values are higher than the ones obtained with a reference sample (La 0.12; Ce 0.19, Th 0.020 and U 0.012 mg kg(-1)), located far from the target area. Internal standardization was used to compensate the non-spectral interference of the different elements present in the sample solution matrix. The chemical elements bismuth (Bi) and indium (In) were chosen as internal standards. In order to control the accuracy of the chemical measurement process, certified samples of pine needles (NBS SRM 1575) were also analyzed. The results obtained show the capability of the investigated method in the determination of the relevant trace metals in the environment.     

Simultaneous speciation of inorganic selenium and antimony in water samples by electrothermal vaporization inductively coupled plasma mass spectrometry following selective cloud point extraction

A new method was developed for the simultaneous speciation of inorganic selenium and antimony in water by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) following selective cloud point extraction (CPE). The method is based on the fact that Se(IV) and Sb(III) could form complexes with diethyldithiocarbamate (DDTC) at pH 6.00, and the complexes were quantitatively extracted into the non-ionic surfactant-rich phase of octylphenoxypolyethoxyethanol (Triton X-114), whereas the Se(VI) and Sb(V) remained as free species in aqueous solutions. Sb(III) and Se(IV) in concentrate were determined by ETV-ICP-MS after proper disposal. The total Se and total Sb were determined by the same protocol after Se(VI) and Sb(V) were reduced by l-cysteine, and Se(VI) and Sb(V) concentrations were obtained by respectively subtracting Se(IV) and Sb(III) from the total Se and the total Sb. Under the optimized conditions, the limits of detection (LODs) were 0.05 microg L(-1) for Se(IV) and 0.03 microg L(-1) for Sb(III), the relative standard deviations (RSDs) were 3.5% for Se(IV) and 4.2% for Sb(III) (C=1.00 microg L(-1), n=5). The proposed method was applied to the speciation of inorganic selenium and antimony in different water samples with satisfactory results.     

Daily concentrations of trace metals in aerosols in Beijing, China, determined by using inductively coupled plasma mass spectrometry equipped with laser ablation analysis, and source identification of aerosols

This paper describes the daily concentrations of trace metals and ionic constituents in the aerosol of Beijing, China from March 2001 to August 2003. Daily PM10 concentrations were also measured from September 2001 to August 2003. The daily average PM10 concentration at Beijing, China from September 2001 to August 2003 was 171+/-117 microg m(-3) (n = 673), which is 5-fold higher than at Yokohama, Japan. Trace metal concentrations were analyzed by using inductively coupled plasma mass spectrometry equipped with a laser ablation sample introduction (LA/ICP-MS), which is a rapid and simultaneous method for multi-element analysis. The daily average metal concentrations in TSP in Beijing from March 2001 to August 2003 were: Al: 3.5+/-2.4 (n = 727), Ti: 0.47+/-0.35 (n = 720), V: 0.013+/-0.010 (n = 716), Cr: 0.019+/-0.015 (n = 618), Mn: 0.24+/-0.16 (n = 730), Fe: 5.5+/-3.9 (n = 728), Co: 0.0046+/-0.0055 (n = 629), Ni: 0.022+/-0.024 (n = 680), Cu: 0.11+/-0.11 (n = 660), Zn: 0.77+/-0.60 (n = 726), As: 0.048+/-0.047 (n = 731), Se: 0.010+/-0.010 (n = 550), Cd: 0.0068+/-0.0082 (n = 709), Sb: 0.033+/-0.036 (n = 687), and Pb: 0.43+/-0.50 (n = 728) (unit, microg m(-3)). All the metal concentrations in TSP in Beijing, China were 1.7-21.8 times higher than those in TSP in the center of Tokyo, Japan. Notably, As concentrations in TSP in Beijing were 20-fold higher than those in Tokyo. Source identification of aerosols in Beijing was carried out by using the chemical mass balance (CMB) receptor model, with the daily concentration of metals in the aerosol. The major primary sources of the aerosol of Beijing were considered to be soil dust and coal combustion. Vehicle exhaust contribution tended to increase.     

The simultaneous determination of arsenic, antimony, bismuth, selenium and tellurium in waters by an inductively coupled plasma/volatile hydride method

A method using inductively coupled plasma spectrometry (ICP) and hydride generation is used to determine As, Sb, Bi, Se and Te simultaneously in both treated and natural waters. Two methods are described, direct analysis and a coprecipitation preconcentration method. Precision (RSD) was less than 10% for solutions of 1 μg l⁻¹ by using the preconcentration method. Recoveries of a wide range of analyte concentrations (0.1–50μg l⁻¹) for sea-water and internal supply water were excellent. Routine application of the method to waters from the rivers Hayle and Gannel, Cornwall are also reported.A time delay experiment was conducted to investigate the stability of the analytes in acidic solution. It was found that all the analytes in an ionic form were stable for up to 8 days.     

Comment on the article 'Radionuclide dating (Pb-210, Cs-137, Am-241) of recent lake sediments in a highly active geodynamic setting (Lakes Puyehue and Icalma-Chilean Lake District)'

The correlation of Cs-137 specific activity profiles with the historical fallout sequence in the study region is essential in sediment cores dating using this technique. The authors of the referenced article considered 1965 the end of Cs-137 fallout in the study region, omitting the South Pacific nuclear test from 1966 to 1974, proved that generated the most intense Cs-137 fallout.     

Determination of the natural stress state in a Brazilian rock mass by back analysing excavation measurements: a case study

The Serra da Mesa Hydroelectric Power Plant, located in the Tocantins river, 210 km north of Brasilia, Brazil, has been completed and power (1200 MW) has been generated since 1998. This project includes one of the largest underground structures in Brazil, totalling 550,000 m³ of underground excavations in rock for the hydraulic circuit which was excavated in very high quality granite. Geotechnical investigations, laboratory tests and geological mapping showed that the rock mass could be considered as a continuous, homogeneous, isotropic and linearly elastic (CHILE) material.

In situ tests, for obtaining the natural stress tensor, namely hydraulic fracturing and small flat jack tests (SFJ), were executed. The hydraulic fracturing tests were performed in two boreholes, at the planned position of the future underground structures. SFJ were executed in a test gallery especially constructed for the purpose. These latter tests confirmed the in situ rock stress data obtained from the hydraulic fracturing tests.

This paper presents a new technique for interpretation of the SFJ results. This is achieved by inputting the SFJ measurements into a 3D program that compiles the influence matrix of the excavated rock mass domain and then, via the least square technique, the determination of the stress tensor. All the equations are fully developed and the methodology is presented in its entirety. The successful application of the methodology is also presented, with comparisons between the results obtained and the in situ stress tensor determined by other methods.