Concentration determination of gold nanoparticles by flame atomic absorption spectrophotometry

Acta Geochimica - While engineered nanoparticles are widely used and maybe eventually released into the environment, natural nanoparticles are also commonly found in the Earth system. Nanoparticles...     

Field determination of copper, manganese and Zinc in sulphide materials by flameless atomic absorption spectrometry

A field-portable analytical method is described for the semi-quantitative determination of Cu, Mn and Zn in oceanic sulphide minerals. Samples were prepared on board ship and analyzed using the AAZ-2 field portable atomic absorption spectrophotometer. The method has general applicability to a variety of field locations at sea or on land. Analyte concentrations ranging from the ppm to percent levels could be determined by selecting the appropriate analytical wavelengths and sample dilution factors. Samples were dissolved using hydrochloric and nitric acids in sealed teflon vessels. Concentrations of Cu, Mn and Zn were determined with an accuracy of approximately 10% when field results were compared with determinations subsequently carried out on the same samples in the laboratory by flame atomic absorption methods.     

原子吸收分光光度法与氢醌容量法测定矿石中金的比对

本文对矿石中金的两种分析方法进行了比对。结果表明原子吸收分光光度法要优于氢醌容量法。     

Decomposition and analysis by atomic absorption photospectrometry of silicate rocks

A rapid and simple method of analysis of silicate rocks using gold crucibles and fluoroboric acid as a solvent of the disintegrated material has been developed. The main elements are determined in a single treatment. The results obtained are comparable to the values recommended for samples of eleven standard rocks.     

原子吸收法测定冰晶石中的钾

文章建立了火焰原子吸收光谱法测定冰晶石中钾的分析方法。样品用高氯酸溶解后,在标准系列加入与待测试液等量的铝和钠来消除样品中大量铝和钠对钾的干扰,用空气-乙炔火焰测定了样品中的钾,测定结果与火焰光度法一致。检出限为：0.057m g/L,相对标准偏差（RSD）为：3.55%-4.14%,回收率为：98.67%-103.2%。     

原子吸收法直接测定摇床样品中的金

建立了原子吸收法直接测定摇床样品中的金的分析方法.采用王水溶样,以10％王水为介质.火焰原子吸收法分光光度计测定摇床样品中的金该方法具有设备投资小、流程短、劳动强度低、速度快、污染小等特点.对比试验结果表明,该方法测定结果和火试金方法相一致.     

原子吸收光谱法测定矿样中金

试样经650℃灼烧,王水（1＋1）冷浸泡分解试样,利用泡沫塑料富集金,采用硫脲溶液解脱金,用火焰原子吸收光谱法测定矿样中的金,本法适用岩石矿物中0.05×10-9以上金的测定。     

石墨炉原子吸收法测定土壤中痕量金检出限的不确定度分析

根据石墨炉原子吸收光谱法对土壤中痕量金进行测定,选取金系列标准浓度测量质量—吸光度工作曲线,连续测定多次空白溶液的吸光度值,计算检出限。通过对其检出限的不确定度的分析,确定了检出限不确定度的因素,计算出其扩展不确定度。能比较直观地了解选择的测试条件、建立的分析方法是否达到现行的相关标准及其灵敏度的要求。     

Geochemistry of molybdenum in some stream sediments and waters

Elevated concentrations of Mo are present in both the waters and sediments of Tenmile Creek, downstream from the large Mo deposit at Climax. Colorado. Concentrations of Mo reach a maximum of 10mg/1 in the water and 384μ/g in the (?) 80 mesh fraction of the sediment. The Mo anomaly extends for more than 80 km downstream from Climax, and results from the mining and milling at Climax. Background Mo concentrations in the nearby mountainous area are < 10μg/l (water) and < 5μg/g (sediment). Immediately below three small unmined Mo-rich orebodies elsewhere in Colorado < 3μg/l Mo are present in the waters and 20–30μg/g Mo in the fine fraction of the sediments.The Mo in the sediment of Tenmile Creek is chiefly adsorbed on coatings of amorphous Fe oxyhydroxide. and is similar to its form below two small, unmined Mo deposits. Mining has not changed the character of the chemical processes responsible for Mo dispersion from the Climax site.A modified version of the WATEQF computer program (Plummeret al., 1976) predicts that Tenmile Creek is undersaturated with respect to ferrimolybdite. molybdenite, powellite, and ilsemannite. The Mo in the stream water occurs as the molybdate ion which can be adsorbed on amorphous Fe oxyhydroxides. These predictions are supported by the absence of Mo minerals in the sediment of Tenmile Creek.     

Metal speciation and attenuation in stream waters and sediments contaminated by landfill leachate

The degree of metal contamination (Zn, Pb, Cu, Ni, Cd) has been investigated in the vicinity of an old unmonitored municipal landfill in Prague, Czech Republic, where the leachate is directly drained into a surface stream. The water chemistry was coupled with investigation of the stream sediment (aqua regia extract, sequential extraction, voltammetry of microparticles) and newly formed products (SEM/EDS, XRD). The MINTEQA2 speciation-solubility calculation showed that the metals (Zn, Pb, Cu, Ni) are mainly present as carbonate complexes in leachate-polluted surface waters. These waters were oversaturated with respect to Fe(III) oxyhydroxides, calcite (CaCO₃) and other carbonate phases. Three metal attenuation mechanisms were identified in leachate-polluted surface waters: (i) spontaneous precipitation of metal-bearing calcite exhibiting significant concentrations of trace elements (Fe, Mn, Mg, Sr, Ba, Pb, Zn, Ni); (ii) binding to Fe(III) oxyhydroxides (mainly goethite, FeOOH) (Pb, Zn, Cu, Ni); and (iii) preferential bonding to sediment organic matter (Cu). These processes act as the key scavenging mechanisms and significantly decrease the metal concentrations in leachate-polluted water within 200 m from the direct leachate outflow into the stream. Under the near-neutral conditions governing the sediment/water interface in the landfill environment, metals are strongly bound in the stream sediment and remain relatively immobile.     

Isotopic variations of dissolved copper and zinc in stream waters affected by historical mining

Zinc and Cu play important roles in the biogeochemistry of natural systems, and it is likely that these interactions result in mass-dependent fractionations of their stable isotopes. In this study, we examine the relative abundances of dissolved Zn and Cu isotopes in a variety of stream waters draining six historical mining districts located in the United States and Europe. Our goals were to (1) determine whether streams from different geologic settings have unique or similar Zn and Cu isotopic signatures and (2) to determine whether Zn and Cu isotopic signatures change in response to changes in dissolved metal concentrations over well-defined diel (24-h) cycles.Average δ⁶⁶Zn and δ⁶⁵Cu values for streams varied from +0.02‰ to +0.46‰ and −0.7‰ to +1.4‰, respectively, demonstrating that Zn and Cu isotopes are heterogeneous among the measured streams. Zinc or Cu isotopic changes were not detected within the resolution of our measurements over diel cycles for most streams. However, diel changes in Zn isotopes were recorded in one stream where the fluctuations of dissolved Zn were the largest. We calculate an apparent separation factor of ∼0.3‰ (^66/64Zn) between the dissolved and solid Zn reservoirs in this stream with the solid taking up the lighter Zn isotope. The preference of the lighter isotope in the solid reservoir may reflect metabolic uptake of Zn by microorganisms. Additional field investigations must evaluate the contributions of soils, rocks, minerals, and anthropogenic components to Cu and Zn isotopic fluxes in natural waters. Moreover, rigorous experimental work is necessary to quantify fractionation factors for the biogeochemical reactions that are likely to impact Cu and Zn isotopes in hydrologic systems. This initial investigation of Cu and Zn isotopes in stream waters suggests that these isotopes may be powerful tools for probing biogeochemical processes in surface waters on a variety of temporal and spatial scales.     

Apparent solubilities of schwertmannite and ferrihydrite in natural stream waters polluted by mine drainage

The apparent solubilities of schwertmannite and ferrihydrite were estimated from the H⁺, OH⁻, Fe³⁺, and SO₄²⁻ activities of the natural stream waters in Korea and mine drainage in Ohio, USA. Both chemical composition of the stream waters and the mineralogy of the precipitates were determined for samples from two streams polluted by coal mine drainage. This study combines these new results with previous data from Ohio, USA to redetermine solubilities. The activities of the dissolved species necessary for the solubility determinations were calculated from the chemical compositions of the waters with the WATEQ4F computer code.Laboratory analyses of precipitates indicated that the main minerals present in Imgok and Osheep creek were schwertmannite and ferrihydrite, respectively. The schwertmannite from Imgok creek had a variable chemical formula of Fe₈O₈(OH)_8−2x(SO₄)_x· nH₂O, where 1.74 ≤ x ≤ 1.86 and 8.17 ≤ n ≤ 8.62. The chemical formula of ferrihydrite was Fe₂O₃· 1.6H₂O. With known mineralogy of the precipitates from each stream, the activities of H⁺, OH⁻, Fe³⁺, and SO₄²⁻ in the waters were plotted on logarithmic activity-activity diagrams to determine apparent solubilities of schwertmannite and ferrihydrite. The best estimate for the logarithm of the solubility product of schwertmannite, logK_s, was 10.5 ± 2.5 around 15°C. This value of logK_s constrains the logarithm of the solubility product of ferrihydrite, logK_f, to be 4.3 ± 0.5 to maintain the stability boundary with schwertmannite observed in natural waters.     

石墨炉原子吸收法测定生物样品中微量钒

生物样品用灼烧法,除去有机物,在浓度为5％的盐酸介质中,加入EDTA和铵盐作为基本改进剂,清除石墨炉原子吸收法测定钒时铜、铁离子的干扰,可直接测定钒．采用标准加入法回收率为96．4-106．8％,相对标准偏差3．95％。     

石墨炉原子吸收法测定土壤中痕量金的不确定度的评定

针对石墨炉原子吸收法测定土壤中痕量金的测定过程,建立了数学模型,分析了其不确定度的来源,对不确定度的各分量进行量化,计算得出合成标准不确定度和扩展不确定度,并以不确定度的形式表达了测定结果。     

火焰原子吸收光谱法测定铝土矿中钾、钠

采用自制封闭溶样器对铝土矿进行处理，在盐酸介质中，用火焰原子吸收光谱仪于波长598．2nm处，测定Na2O的吸光度；于波长766．7nm处，测定K2O的吸光度。此方法适合对铝土矿中钾、钠的测定，具有选择性好，操作简便、快速，测定结果准确等优点。     

石墨炉原子吸收光谱法测定土壤样品中镉

采用磷酸氢二铵作基体改进剂塞曼扣背景石墨炉原子吸收光谱法测定土壤样品中镉，方法检出限DL=0．012μg／g，精密度RSD在3．55％～7．33％，满足了土壤样品中镉测定的镉质量要求。     

Biogeochemical processes controlling midday ferrous iron maxima in stream waters affected by acid rock drainage

The biogeochemical cycling of Fe in acid rock drainage (ARD) streams has presented ongoing challenges to reactive solute transport modeling. Previous studies have relied on the pH-dependent solubility of Fe oxides as the main control of the mid-day Fe(II) maxima concentration in ARD streams. In this study, the authors assess the potential for Fe(II)-oxidizing reactions, including the Fenton and microbial oxidation reactions, to constrain the mid-day Fe(II) maxima concentration. At mid-day, pseudo-equilibrium between Fe(II) oxidizing reactions and photoreduction was assumed in order to evaluate the observed Fe(II) maxima and develop an equation to represent this steady state scenario. This steady state condition is assumed only while light intensity, reactivity of oxides and dissolved organic matter (DOM), and microbial populations remain approximately constant. Three Rocky Mountain ARD streams with known values for Fe(II) were evaluated and average photoreduction rates ranging from 5.56×10⁻⁴ to 1.39×10⁻³ μM/s were found during mid-day steady state Fe(II) maxima. Application of Fe redox biogeochemistry to reactive solute transport modeling may improve predictive capabilities of various trace metal and solute interactions incorporated with the cycling of Fe within ARD streams. Further, model improvement of Fe cycling may enable more accurate remediation predictions for ARD streams.     

石墨炉原子吸收光谱法测定地质样品中微量银

对石墨炉原子吸收光谱法测定地质样品中微量银进行了研究。样品经四酸溶解,在3mol/L的HCl介质中以EDTA-抗坏血酸溶液作为基体干扰改进剂,用石墨炉原子吸收光谱法测定地质样品中微量银。方法检出限为0.051ng/mL,精密度(RSD,N=11)5.91%~12.83%。能满足地质样品中w(Ag)/10-6=0.03~5范围内银测定的准确度和精密度的要求。     

Speciation of aluminum in the stream waters from the Susquehanna River watershed, Chesapeake Bay

 The aim of this paper was to analyze the processing and transport of aluminum speciation through the terrestrial and aquatic ecosystems of the Chesapeake Bay landscape. Stream waters were sampled in 14 different streams from the Susquehanna River watershed to the upper reach of Chesapeake Bay. The basic water quality data were documented and Al speciation was evaluated by modified MINEQL computer model. It was found that the increase in acidity in some of the stream waters near New York were closely linked with a marked decline in basic cation concentrations. In these areas, the sum of the toxic forms of Al³⁺ plus AlOH²⁺ and Al(OH)₂ ⁺ concentrations exceeds the critical level of 5 μmol l^–1. A potential threat from aluminum may occur. Received: 3 January 2000 · Accepted: 21 March 2000     

原子吸收法测定岩石矿物中金含量

试样中的金用王水分解,泡沫塑料富集,原子吸收法测定。此法简捷快速,仪器稳定性好,准确度高。