Determination of the Trace Refractory Elements V, Nb and Ta in Environmental Samples by ICP-MS After Separation and Preconcentration with Nanometre-Sized Alumina Microcolumns Following Chemical Modification by Gallic Acid     

Xuli Pu  Chaozhang Huang  Bin Hu  Zucheng Jiang 《Geostandards and Geoanalytical Research》2006,30(2):97-105

Nanometre-sized alumina was chemically modified with gallic acid (GA) and used as a solid phase adsorption material for the determination of trace amounts of V, Nb and Ta in natural water, soil and stream sediment samples by inductively coupled plasma-mass spectrometry. The effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analytes were investigated. The results showed that V, Nb and Ta could be adsorbed at pH 4.0 and recovered with 1 ml of 2.0 mol l^-1 HCl. Under optimised conditions, the adsorption capacity of GA-modified nanometre-sized Al₂O₃ was found to be 7.0, 8.9, 13.3 mg g^-1 for V, Nb and Ta, respectively. The limits of detection were as low as 0.25, 0.24 and 0.66 ng l^-1 for V, Nb and Ta, respectively with a concentration factor of fifty. The recovery of V, Nb and Ta for spiked water samples was between 85.7 and 116%. The developed method has also been applied to the determination of trace V, Nb and Ta in soil and stream sediment certified materials, and the determined values were in a good agreement with the certified values.  相似文献   

Neutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2004–2005     

L. Paul Bédard 《Geostandards and Geoanalytical Research》2006,30(3):183-186

These technologically mature techniques occupied a stable to modestly increasing sector of the spectrum of analytical methods in Earth and environmental sciences in 2004–5. Despite this, several notable advances were reported in this two year period. In the field of X-ray fluorescence spectrometry, these included the development of portable synchrotron and total reflection instruments, the use of pyroelectric crystals as X-ray generators, introduction of high-purity Ge detector arrays, and the development of an XRF imaging spectrometer with the capability of mapping analytes and X-ray intensity ratio. Atomic absorption s spectrometry saw major work published on high-resolution continuum source AAS (HR-CS AAS) involving the development of a xenon short-arc lamp. Other advances included the use of laser wave mixing in a graphite furnace tube (with a claimed detection limit of 10–¹⁶ g g-¹), solid sampling and ultrasound in sample preparation. Neutron activation analysis saw two innovations that may herald future growth in this technique, namely a neutron source free of a nuclear reactor and a detector operating at room temperature.  相似文献   

Thorite versus huttonite: stability, electronic properties and X-ray emission spectra from first-principle calculations     

Igor R. Shein  Konstantin I. Shein  Alexander L. Ivanovskii 《Physics and Chemistry of Minerals》2006,33(8-9):545-552

The structural, electronic properties and stability of thorium orthosilicate ThSiO₄ polymorphs: thorite and huttonite are investigated by means of the full-potential linearized augmented-plane-wave method with the generalized gradient approximation for the exchange-correlation potential (FLAPW-GGA). The forbidden gaps of thorite and huttonite are estimated at about 7.8 and 7.6 eV, respectively. It is found that Th5f states in ThSiO₄ partially overlap with occupied O2p bands. The data obtained showed that thorite is more stable than huttonite; in turn both ThSiO₄ polymorphs are unstable with respect to their constituent binary oxides (thorianite ThO₂ and α-quartz SiO₂) in agreement with the experiments. The theoretical shapes of X-ray emission (XES) (Si,O)Kα,β spectra for thorite, huttonite as well as for SiO₂ and ThO₂ are calculated and discussed. We show that the XES spectroscopy near the (Si,O)K edge may be very useful technique not only for detailed investigation of the bulk-electronic structure of Th silicates but also for the phase analysis of complex mineral samples containing these species.  相似文献   

High resolution X-ray fluorescence spectrometry for water analysis of metals in East China Sea     

Y. Zou K. Yokoi H. Ohashi T. Tochio Y. Ito T. Shoji T. Matsuno 《中国地球化学学报》2006,25(B08):152-153

Within the last century, water pollution has become a major problem throughout the world. Aquatic systems are endangered by many different types of pollution but one of the most threatening is contamination by heavy metals, for example, Cd, etc. The presence of these metals is mainly due to industrial wastes or mining wastes being improperly treated and dumped into the water supply. The contamination may damage marine organisms or create changes in the aquatic environment. For these reasons, monitoring the concentrations of trace elements in rivers, coastal waters and open seawater is very important for environmental conservation. Like many countries in the world, China is facing the serious problem of water pollution in its aquatic system. Areas like the Yangtze River have been industrialized very quickly, and without proper waste control practices the pollution levels have increased with the economic growth. The Yangtze River covers thousands of square kilometers and crosses more than half of China before reaching the East China Sea.  相似文献   

Open burning of wastes as the source of environmental contamination by POPs     

Sergey V. Kakareka Tamar I. Kukharchyk 《中国地球化学学报》2006,25(B08):177-178

In the paper the procedure for and results of a test study of a few persistent organic pollutants - polycyclic aromatic hydrocarbon （PAH）, polychlorinated biphenyls （PCB） and hexachlorobenzene （HCB） emission from the open burning of different types of wastes （domestic wastes, agricultural debris, landscape cleating debris, etc.） are discussed. The open burning of agricultural debris and landscape-clearing debris is widely applied in rural areas and small towns and in allotment gardens for the recovery of that part of wastes that can not be utilized for compost preparation. This process is most typical during the autumn season and to a lesser degree during spring. Burning occurs usually in bon fires. Burning modes differ depending on the volume of material burnt, the waste moisture content, the weather conditions, etc. During this process part of domestic wastes （polluted wood, paper, chipboard, films, plastics, etc.） are burned also. Investigations included the collection and preparation of combustible material, the simulation of open burning processes, particulate and gas emission sampling, chemical analysis of sample and data processing. Sampling procedures and sample preparation were agreeable to the emission sampling standards. The aerosol and vapour phases of POPs were collected by ordinary sampling train with pumping of waste gases through filter and solid sorbent （polyurethane foam）. For the measurements of PAH in emission, gas chromatography and mass spectrometry were used which make it possible to identify and determine 16 PAH compounds in the samples; this method was used for HCB determination also. Gas chromatography with ECD detector was used for PCB measurement. It was detected that the levels of PAH emission from wastes uncontrolled burning of wastes vary greatly. Influencing factors are composition and properties of refuse, temperature and mode of burning, level air supply. Generally, the increase of content of wood leads to the increase of PAH in emission. PAH emission also increased with increasing temperature of burning. The highest PAH values are characteristic of emissions from domestic refuse burning. Practically, all naphthalene, acenaphthylene, acenaphthene （from 60% to 100% of their total mass） and fluorene （14%-99%） were emitted in gaseous form.  相似文献   

Carius管溶样一标准加入电感耦合等离子体质谱法测定土壤中碘     

《岩矿测试》2006,25(1):19-21

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Conceptual model about the interaction between El Ni?o/Southern Oscillation and Quasi-Biennial Oscillation in far west equatorial Pacific     

Liu Qinyu  Liu Zhengyu  Pan Aijun 《中国科学D辑(英文版)》2006,49(8):889-896

Interaction between the Quasi-Biennial Oscillation in far west equatorial Pacific (QBOWP) and the El Ni?o/Southern Oscillation (ENSO) is studied using a new conceptual model. In this conceptual model, the QBOWP effects on ENSO are achieved through two ways: (1) the oceanic Kelvin wave along equatorial Pacific, and (2) the Atmospheric Walker Circulation anomaly, while ENSO effects on QBOWP can be accomplished by the atmospheric Walker Circulation anomaly. Diagnosis analysis of the model results shows that the Atmospheric bridge (Walker circulation) plays a more important role in interaction between the ENSO and QBOWP than the oceanic bridge (oceanic Kelvin wave along equatorial Pacific); It is found that by the interaction of the ENSO and QBOWP, a free ENSO oscillation with 3–5 years period could be substituted by a oscillation with the quasi-biennial period, and the dominant period of SST anomaly and wind anomaly in the far west equatorial Pacific tends to be prolonged with enhanced ENSO forcing. Generally, the multi-period variability in the coupled Atmosphere-Ocean System in the Tropical Pacific can be achieved through the interaction between ENSO and QBOWP.  相似文献   

Fracture Toughness Measurements and Acoustic Emission Activity in Brittle Rocks   总被引：1，自引：0，他引：1  

M. H. B. Nasseri  B. Mohanty  R. P. Young 《Pure and Applied Geophysics》2006,163(5-6):917-945

Fracture toughness measurements under static loading conditions have been carried out in Barre and Lac du Bonnet granites. An advanced AE technique has been adopted to monitor real-time crack initiation and propagation around the principal crack in these tests to understand the processes of brittle failure under tension and related characteristics of the resulting fracture process zone. The anisotropy of Mode I fracture toughness has been investigated along specific directions. Microcrack density and orientation analysis from thin section studies have shown these characteristics to be the primary cause of the observed variation in fracture toughness, which is seen to vary between 1.14 MPa.(m)^1/2 and 1.89 MPa.(m)^1/2 in Barre granite. The latter value represents the case in which the crack is propagated at right angles to the main set of microcracks. The creation of a significant fracture process zone surrounding the propagating main crack has been confirmed. Real-time imaging of the fracture process and formation of fracture process zone by AE techniques yielded results in very good agreement with those obtained by direct optical analysis.  相似文献   

同位素稀释质谱法测定塑料闪烁体中掺杂锂同位素含量   总被引：1，自引：0，他引：1  

刘雪梅龙开明  贾宝亭汤磊 《岩矿测试》2006,25(3):243-245

介绍了用同位素稀释质谱法（IDMS）测定塑料闪烁体中掺杂^6Li含量的方法。建立了样品的灰化、溶解程序，并对质谱条件进行了探索。实验表明，在300oC碳化2h，升温至500℃灰化5h后，用浓硝酸可以将样品完全溶解，在质谱测量时采用磷酸作为发射剂，可以得到大而稳定的离子流。在优化的实验条件下，塑料闪烁体中掺杂^6Li定量分析测定结果的相对标准偏差小于0．4％（n=11）。  相似文献   

碳酸钙共沉淀-火焰原子吸收光谱法测定卤水中痕量铜铅锌     

仲金虎  王洪彬 《岩矿测试》2006,25(1):89-90

以碳酸钙共沉淀卤水中的痕量Cu、Pb、Zn，用火焰原子吸收光谱法测定。对试剂的加入量、富集时间、酸度等影响因素进行了实验，选择了最佳的共沉淀条件。方法已用于卤水分析，加标回收率为Cu94．0％～97．6％、Pb94．0％。102％、Zn93．4％-102％。对卤水样品6次测定的相对标准偏差为Cu0．49％、Pb0．79％、Zn1．85％。  相似文献