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微波消解-氢化物发生原子荧光光谱法测定粉煤灰中的硒 总被引：2，自引：2，他引：0
粉煤灰中含有的硒元素较高,有综合利用价值.由于基体的复杂性,并未形成成熟可靠的测定技术.本文参考煤炭样品和土壤样品中硒的原子荧光光谱分析方法,采用氢化物发生-原子荧光光谱法测定粉煤灰中的硒.样品经氢氟酸-硝酸-双氧水体系微波消解得到清亮、透明的消解液,消解液经浓盐酸还原后,加入三价铁盐消除共存元素的干扰,所加的铁盐量不干扰硒的测定.方法检出限为0.020 μg/g;平行测定5份粉煤灰样品,相对标准偏差低于4.2％;加标回收率为94.0％～105.0％.应用建立的方法对煤飞灰标准物质进行分析,测定值与标准值基本相符;对不同地区的实际粉煤灰样品进行分析,证实方法可靠,可用于粉煤灰中硒元素的测定. 相似文献
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水浴浸提-氢化物发生-原子荧光光谱法同时测定地质样品中痕量砷和汞 总被引：2，自引：2，他引：0
采用盐酸-硝酸混合酸(盐酸-硝酸-水体积比3∶1∶4)水浴浸取地质样品,在样品消解后的母液中直接加入硫脲-抗坏血酸混合溶液,以氢化物发生-原子荧光光谱法同时测定地质样品中的痕量砷和汞。方法检出限为砷0.033 6 ng/mL,汞0.003 7 ng/mL;相对标准偏差(RSD,n=1)为砷1.1%,汞3.0%。对国家一级标准物质GBW 07109~GBW 07114、GBW 07301~GBW 07312、GBW 07401~GBW 07408中的砷和汞进行测定,测定值与标准值相吻合。 相似文献
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氢化物发生-原子荧光光谱法测定地球化学样品中痕量铋 总被引：4，自引：0，他引：4
样品经王水溶解后,加入KMnO4溶液氧化,草酸除去过量KMnO4后的体系,直接用氢化物发生原子荧光光谱法测定地质样品中痕量Bi。方法使Au、Pd、As、Sb、Se、Te等元素的允许量大为提高,减少了不同测定体系中共存元素对Bi测定的干扰。方法的检出限(6s)为0.042μg/g,精密度(RSD,n=12)为1.88%~5.57%。经国家一级地质标准物质验证,测定值与标准值吻合。 相似文献
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原子荧光光谱法(AFS)具有灵敏度高、结构简单、容易操作等优点,但目前测定土壤和沉积物中的硒等元素的标准方法所采用的消解过程繁琐,易产生干扰。沸水浴可以把土壤和水系沉积物中硒提取完全,本文根据样品中元素丰度和仪器性能,将AFS测定Se的干扰分为Cu和Pb两大类,根据实验提出在水浴消解液加入浓盐酸(不宜加入硫脲-抗坏血酸),通过增加溶液酸度和Cl~-浓度,即保持样品中盐酸浓度高于23%,可抑制Cu~(2+)还原为Cu~0和Pb~(4+)生成PbH_4,有效降低了Cu的负干扰和Pb的正干扰,提高了AFS测定Se的精密度和准确度。本方法测定Se的检出限为0.008mg/kg,测试标准物质的相对标准偏差为0.5%～11%,相对误差为-16.3%～9.5%;比行业标准HJ 680—2013的检出限(0.01mg/kg)、精密度(0.79%～23.1%)和准确度等技术指标更佳。 相似文献
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氢化物发生-电感耦合等离子体发射光谱法同时测定土壤中的痕量砷铜铅锌镍钒 总被引：1，自引：1，他引：0
土壤中砷的测定方法多采用氢化物发生-原子荧光光谱法(HG-AFS);电感耦合等离子体发射光谱法(ICP-OES)在多元素同时测定方面应用普遍,但测定砷的检出限稍高。氢化物发生技术与ICP-OES两者联用也多有研究,较大幅度降低了砷的检出限,已能实现砷锑铋汞等元素的同时测定。但联用技术只能应用于测定能够发生氢化反应的元素,无法实现易氢化元素和难氢化元素的同时测定。本文通过改进ICP-OES仪器的进样装置,采用氢化反应气与ICP-OES雾化气双管路同时进样的方法,实现了一次溶样、一台设备同步测定样品中的砷和多种金属元素。土壤样品经氢氟酸、硝酸、高氯酸、盐酸溶解后,用10%盐酸提取,用硫脲-抗坏血酸溶液将砷元素预还原为+3价后双流路同时进样测定。对于溶液中共存的离子,高于1.0mg/L的La和Dy对砷测定有干扰;低于50.0mg/L的K、Na、Ca、Mg、Fe,低于20.0mg/L的Pb、Mo、Zn、Cu、Ba、Ti、Mn、Ni、Sr、V、Cr,低于10.0mg/L的Co、Ag、U、Cd、Li、Au对砷测定无影响。本方法提高了砷的测定灵敏度,又充分利用多元素同测的优势,实现了同时测定易氢化的痕量砷和难氢化的铜、铅、锌、镍、钒等元素。方法精密度高(RSD5%),经土壤标准物质验证方法可靠,适合痕量砷与其他元素的同步测定。 相似文献
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应用氢化物发生原子荧光光谱法(HG-AFS)测定钨矿石和钼矿石中的砷,钨钼铜铅锌铋镉等共存元素在不经分离或不加掩蔽剂的情况下对砷测定产生严重干扰。本文采用盐酸-硝酸(5∶1)水浴加热分解样品,加入柠檬酸-碘化钾掩蔽共存元素,促进这些元素还原成低价离子或者直接形成沉淀以消除干扰;再加入硫脲-抗坏血酸还原后直接用HG-AFS测定砷量。砷的检出限为0.014μg/g,测定范围为0.2~2000μg/g,方法精密度为0.7%~7.5%,加标回收率为92.3%~102.9%。本方法与国家标准方法相比,检出限低,检测范围宽,干扰元素不经分离可直接测定砷的含量。 相似文献
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氢化物发生-电感耦合等离子体发射光谱法同时测定土壤中痕量砷锑铋汞 总被引：4，自引：4，他引：0
土壤样品用水浴加热王水溶解1 h,在10%的盐酸介质下,用0.5 L/min的载气流量,10 g/L的硼氢化钠-氢氧化钠作为还原剂,将自行设计的一种新型氢化物发生器与电感耦合等离子体发射光谱法(ICP-AES)联用测定痕量砷、锑、铋、汞,一次溶样即可实现多元素在同母液同条件下同时测定。方法检出限为0.01～0.06 ng/g,加标回收率为92.0%～102.0%,精密度(RSD)低于5%。此方法通过加入抗坏血酸-硫脲溶液预先将砷和锑还原,汞的测定不受还原剂的影响,同时解决了目前多元素分次测量带来的不便和试剂消耗多等问题,样品前处理及测量过程快速、简单,无记忆效应的影响,适合环境样品中痕量砷、锑、铋、汞的同时测定。 相似文献
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X射线荧光光谱法分析不同类型岩石中10种主量元素的测试能力验证 总被引：4，自引：3，他引：1
以28个不同类型岩石标样作外标,用玻璃熔片法制样,采用经验系数法进行基体校正,建立了X射线荧光光谱法(XRF)测定不同类型岩石中硅铝钙镁等10种主量元素的分析方法。该方法被用于参与GeoPT分析测试能力验证,15年来分析了23个不同类型的岩石验证样品。经验证该方法对SiO_2、Al_2O_3、K_2O和CaO具有非常好的分析效果(所有测定结果的|Z|2);对于MgO、MnO、TiO_2和Na_2O四个元素,尽管各有一个样品的分析结果的|Z|2,这主要是样品与标样的基体差异较大造成了低含量样品测定结果超差,但依然可获得好的分析效果;当TFe_2O_31.0%,P_2O_5含量在0.08%~0.80%区间时,分析结果的|Z|2,满足分析期望。总体上所建立的XRF分析方法稳定,可满足应用地球化学实验室测试不同类型岩石中10种主量元素的分析期望。 相似文献
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电气石是一类含硼的铝硅酸盐矿物,化学成分复杂、化学稳定性强,不易湿法分解,B_2O_3含量较高,导致其主次量元素的同时测定存在一定困难。本文采用熔融法制样,建立了X射线荧光光谱法测定电气石Na_2O、MgO、Al_2O_3、SiO_2、P_2O_5、K_2O、CaO、TiO_2、V_2O_5、Cr_2O_3、MnO、TFe_2O_3等主次量元素的分析方法。样品与四硼酸锂-偏硼酸锂-氟化锂(质量比为4.5∶1∶0.4)混合熔剂的稀释比例为1∶10,消除了粒度效应和矿物效应;在缺少电气石标准物质的情况下,选择土壤、水系沉积物及多种类型的地质标准物质绘制校准曲线,利用含量与电气石类似的标准物质验证准确度,测定结果的相对标准偏差小于4.2%。采用所建方法测定四种不同类型电气石实际样品,测定值与经典化学法基本吻合。本方法解决了电气石不易湿法分解和硼的干扰问题,测定结果准确可靠,与其他方法相比操作简便,分析周期短。 相似文献
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Major element compositions of 36 bulk samples and 41 clay samples, which were obtained from 47 topsoils collected in monsoonal eastern China, were investigated with conventional wet chemistry and X-ray fluorescence (XRF) spectrometry, respectively. Based on major element analyses, the mobility of major elements and latitudinal distributions of SiO2/Al2O3 ratio, chemical index of alteration (CIA), chemical index of weathering (CIW) and weathering index of Parker (WIP) were analyzed. Meanwhile, the suitability of these chemical weathering indices to topsoils in monsoonal eastern China and its controls were discussed.These investigations indicate that Na, K, Ca, Mg, and Si are relatively depleted, while Mn, P, Fe and Ti are relatively enriched in topsoils of the study area by comparison with their contents in the upper continent crust (UCC), and that alkali metal (Na, K) and alkaline earth metal (Ca, Mg) elements are generally easier to be depleted from their parent materials than other major elements during chemical weathering. The latitudinal distributions of CIA, CIW and WIP show that they are suitable to both bulk and clay samples, but SiO2/Al2O3 is only suitable to clay samples, not suitable in bulk ones. All these investigations indicate a significant dependence of grain-size in major element abundance and latitudinal distributions of SiO2/Al2O3, CIA, CIW and WIP, but parent rock type has little effect on them, except its impact on the latitudinal distribution of WIP in clay samples. The significant grain-size dependence probably indicates the presence of unaltered minerals in bulk samples, thus we suggest that clay samples are more suitable to investigating chemical weathering of sediments on continents than bulk samples. The trivial effect of parent rock type probably indicates a relatively uniform chemical weathering on various parent rocks. Correlation analyses indicate that climate is the dominant control of chemical weathering of topsoils in the study area, and the significant latitude effect indicated by the spatial distributions of chemical weathering indices actually reflect the climate control on chemical weathering of topsoils.Chemical weathering indices actually reflect the integrated weathering history in the study area. Besides the dominant control of climate, other factors like tectonics, parent rock, biology, landform and soil depth and age might also have some effect on the chemical weathering of topsoils in the study area, which needs further research. 相似文献
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Jing Wang Ben-Xun Su Bing-Yu Gao Wen-Jun Li Meng-Meng Cui Xia Liu Yang Luo Qi-Qi Pan Li-Hui Jia Li Su Kai-Yun Chen 《Geostandards and Geoanalytical Research》2023,47(3):683-695
Four natural chromite samples (LBS13-04, LBS13-06 and LBS13-13) from the Luobusa ophiolite (China) and 16SW2-6 from the Stillwater Complex (USA) were developed as reference materials for in situ element microanalysis. Approximately 8 g of chromite fragments with grain sizes of 0.5–1.5 mm from each chromite sample were separated under a binocular microscope and analysed by EPMA, XRF, LA-ICP-MS and solution nebulisation ICP-MS techniques for major and trace elements at six laboratories. The results show that the four chromite samples are homogeneous with respect to MgO, Al2O3, Cr2O3, FeO, Sc, Ti, V, Mn, Co, Ni, Zn and Ga. These samples are thus suitable to be used as reference materials for in situ microanalysis. 相似文献
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Jaya K. Gurung Hiroaki Ishiga Mohan S. Khadka Nav R. Shrestha 《Environmental Geology》2007,52(3):503-517
The geochemical analyses of fluvial-lacustrine aquifer sediments of the Kathmandu Valley have been made as a step in assessing
the environment for the mobilization of arsenic in groundwater. Elements measured by X-ray fluorescence (XRF) include 4 major
oxides (Fe2O3, TiO2, CaO, P2O5) and 14 trace elements (As, Pb, Zn, Cu, Ni, Cr, V, Sr, Y, Nb, Zr, Th, Sc and TS). Elution tests of 15 selected core samples
were also carried out to determine the potential leaching of arsenic from the sediments. The XRF results show that average
bulk concentrations of the major oxides and trace elements are similar to modern unconsolidated sediments and average upper
continental crust. However, the abundance of elements varies with grain size, with higher concentrations in finer-size grades.
Variations in elemental abundances within the basin are strongly controlled by sediment facies. The elution tests show that
greater amounts of arsenic are generally eluted from the fine sediments, although the rates are variable. The results overall
suggest that As concentrations in the bulk sediments are not a controlling factor for elevated As in the Kathmandu Basin groundwater,
and the roles of other factors such as redox conditions and organic matter contents are likely to be more significant. 相似文献
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Principal components analysis is used to study the chemical compositions of pyroxenes of five Apollo 12 specimens. Important correlations recognized in the variation of oxide weight per cent are: MGO, Al2O3, SiO2| CaO, TiO2, FeO MgO, Al2O3, SiO2| FeO MgO, SiO2, FeO | Al2O3, CaO, TiO2 where the oxides on one side of the bar are correlated positively with each other and negatively with the oxides on the other side. Several other similarly distinct relationships with significantly less variance could be noted. These correlations indicating substitutional relationships can be interpreted as representative of stable and metastable trends of crystallization by using crystal-chemical and thermodynamic information. The per cent variance of pyroxene groups with characteristic trends in each specimen can be evaluated and interpreted in terms of history of crystallization. Distribution of Fe and Mg in certain pairs of olivine and pyroxene, which are found in contact in the rock and which may have crystallized simultaneously, is useful in recognizing the tendency towards chemical equilibrium in FeMg distribution during a limited interval in the liquidus or subsolidus stages. 相似文献
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The relative stabilities of orthozoisite, Ca2Al3[O|OH|Si2O7|SiO4], space group Pnma, and the monoclinic polymorph, clinozoisite, space group P21/m, have been investigated using calculations based on density functional theory. It is found that orthozoisite is more stable
than clinozoisite by about 1 kJ mol−1 at zero pressure in the athermal limit. The bulk moduli of the two polymorphs have been calculated to be Bortho=117.5(1.7) GPa and Bclino=136(4) GPa.
Received: 20 March 2000 / Accepted: 26 February 2001 相似文献
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Lüyun Zhu Yongsheng Liu Zhaochu Hu Qinghai Hu Xirong Tong Keqing Zong Haihong Chen Shan Gao 《Geostandards and Geoanalytical Research》2013,37(2):207-229
Fused glass prepared without the addition of a flux is generally more homogeneous than a pressed powder pellet and thus ideal for analysis of bulk samples by LA‐ICP‐MS. In this work, a new glass‐making method using a boron nitride crucible was developed to prepare homogenous glass samples from silicate rock powder. The apparatus consisted of a small boron nitride vessel with net volume of about 34 mm3 and two molybdenum strips. Applying the summed metal oxide normalisation technique, both major and trace element contents in the fused glass were measured by LA‐ICP‐MS. Analyses of five geochemical reference materials (spanning the compositional range basalt–andesite–rhyolite) indicated that the measured SiO2, Al2O3 and P2O5 contents matched the preferred values to within 5%, and the other major elements generally matched the preferred values to within 8%. Except for the transition metals, the measured trace element contents generally matched the preferred values to within 10%. Compared with the iridium heater method developed by Stoll et al. (2008), element volatilisation during high‐temperature melting was effectively suppressed in our method, but metal segregation caused by reduction of BN may cause loss of Cr, Ni and Cu. Although analysis with a large spot size has the advantage of improving counting statistics, matrix effects induced by mass loading of the ICP may hamper the accurate determination of some elements. 相似文献
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Kamal Abou Elmagd Ashraf Emam Mohamed Wahbi Ali-Bik Muhammad Hazem 《Arabian Journal of Geosciences》2018,11(13):355
The present work assesses the potential industrial uses of Paleocene limestone deposits, Garra Formation in Sinn El-Kaddab Plateau, South Western Desert of Egypt, based on their mineralogy and geochemical characteristics. Eighty-six limestone samples collected from ten stratigraphic columnar sections were analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Petrographically, Garra limestone deposits consist dominantly of benthic foraminiferal wackestone and packstone microfacies. The XRD data revealed dominance of low-Mg calcite as essential carbonate mineral in the studied limestone. The bulk rock XRF results revealed CaO (29.28–55.75%) with an average of 52.74%. The CaO exhibits a strong negative correlation with MgO, SiO2, TiO2, Al2O3, and moderate negative correlation with Fe2O3 which indicates that the contribution of these elements is mainly due to detrital input. On the other hand, Al2O3 and Na2O contents exhibit significant negative correlation with loss of ignition (LOI) wt% indicating their incorporation within terrigenous matrix. The average Sr content attains 1297 ppm indicating deposition in temperate marine environment. The average molar CaCO3% values of bulk samples have been computed for individual columnar sections to determine the purity status of Garra limestone deposits. They range from impure (CaCO3%?=?79.92%) to high-pure (CaCO3%?=?97.76%) limestone. Therefore, Garra limestone deposits have extremely valuable uses in a wide spectrum of industrial applications including Portland cement, steel, ceramics, whiting, chemical uses, paper, and feed stuff. 相似文献
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A. Zeh 《Journal of Metamorphic Geology》2001,19(4):329-350
Generally, P–T pseudosections for reduced compositional systems, such as K2O–FeO–MgO–Al2O3–SiO2–H2O, Na2O–K2O–FeO–MgO–Al2O3–SiO2–H2O and MnO–K2O–FeO–MgO–Al2O3–SiO2–H2O, are well suited for inferring detailed P–T paths, comparing mineral assemblages observed in natural rocks with those calculated. Examples are provided by P–T paths inferred for four metapelitic samples from a 1 m2 wide outcrop of the Herbert Mountains in the Shackleton Range, Antarctica. The method works well if the bulk composition used is reconstituted from average mineral modes and mineral compositions (AMC) or when X‐ray fluorescence (XRF) data are corrected for Al2O3 and FeO. A plagioclase correction is suitable for Al2O3. Correction for FeO is dependent on additional microscopic observations, e.g. the kind and amount of opaque minerals. In some cases, all iron can be treated as FeOtot, whereas in others a magnetite or hematite correction yields much better results. Comparison between calculated and observed mineral modes and mineral compositions shows that the AMC bulk composition is best suited to the interpretation of rock textures using P–T pseudosections, whereas corrected XRF data yield good results only when the investigated sample has few opaque minerals. The results indicate that metapelitic rocks from the Herbert Mountains of the Northern Shackleton Range underwent a prograde P–T evolution from about 600 °C/5.5 kbar to 660 °C/7 kbar, followed by nearly adiabatic cooling to about 600 °C at 4.5 kbar. 相似文献