首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
石墨炉原子吸收分光光度法测定土壤样品中痕量镉   总被引:2,自引:0,他引:2  
董丽  沈谷苗 《江苏地质》2004,28(1):42-44
研究了土壤样品中痕量镉的石墨炉原子吸收分光光度法测定最佳条件以及磷酸二氢铵与硝酸镁作基体改进剂对测定镉的基体改进效应,并比较了两种试样分解体系。方法检出限为0.01pg/L,精密度(RSD,n=8)为3.29%-7.69%,经国家一级标准物质分析验证,结果与标准值符合。  相似文献   

2.
李中玺  周丽萍 《岩矿测试》2006,25(3):233-238
用D201阴离子交换树脂富集样品中的痕量Cd,使Cd与共存干扰元素Cu、Ni、Pb、Zn有效分离,消除了这些元素对镉蒸气发生的干扰,从而建立了断续流动在线分离富集-蒸气发生原子荧光光谱法测定复杂环境样品中痕量Cd的分析方法。方法的检出限为3ng/L(3σ);测定精密度(RSD)为1.9%(对1μg/L Cd,n=11)。用该方法对国家一级标准物质(土壤、水系沉积物和岩石)中的痕量镉进行了测定,结果与标准值相符。  相似文献   

3.
碱性模式氢化发生原子荧光光谱法测定地质样品中痕量锗   总被引:7,自引:3,他引:7  
实验选择了“碱性模式”氢化物发生-原子荧光光谱法测定痕量锗体系的最佳仪器和试剂条件,详细研究了Cu、CO、Ni、Au、Ag、Bi、Sb、Fe、Cl等元素的干扰情况及消除方法;对矿样的分解方法进行对比研究,选择出合理的样品分解方式。方法检出限为1.3μg/L,样品测定精密度较好,RSD为3.42%(n=12)。对多种国家一级标准物质进行测定,结果与标准值相符合。方法适用于多种地盾物料中痕量锗的测定。  相似文献   

4.
生物样品用艾斯卡熔剂分解,强酸性阳离子交换树脂静态吸附分离大量Na^+等阳离子后,采用Fe^3+-SCN^--NO2^-催化体系分光光度法测定痕量碘。通过正交实验确定了催化反应的最佳实验条件。方法检出限(6s)为0.13μg/g,方法精密度(RSD,n=12)为3.69%~8.28%。用国家一级生物标准物质进行验证,测定值与标准值相符。  相似文献   

5.
沸石的活化处理及其对铅、钴的吸附性研究   总被引:6,自引:2,他引:4  
易发成 《矿物岩石》2005,25(3):118-121
通过对沸石的活化方法和其基本物化性能(主要包括化学成分、阳离子交换容量、密度、比表面积、孔径、渗透系数及热稳定性)及Pb^2+,Co^2+离子的吸附性能的初步研究认识到:1)经过酸化并经热处理后的沸石的阳离子交换容量(CEC)明显高于未经处理的原土;2)通过实验得出粒度为100目的天然沸石经酸活化处理后在300C下热活化,1.5h后测得离子交换量为最佳;3)沸石的密度为1.789g/cm^3;渗透系数为0.087cm/s(20℃);体积平均粒径为13μm;比表面积为190.67m^2/g,平均孔径为102.27nm;4)沸石对重金属离子的吸附实验表明沸石对重金属离子Pb^2+的吸附性能优于Co^2+,20min时Pb^2+和Co^2+的吸附比(Rd)分别为20238.8ml/g及63.8ml/g;Pb^2+和Co^2+去除率分别为99.50%和40.00%。  相似文献   

6.
研究了碘化钾-甲基异丁基甲酮(KI—MIBK)萃取-火焰原子吸收分光光度法连续测定地球化学样品中痕量银、镉和铊的主要条件。通过对火焰原子吸收分光光度计气路控制系统及雾化器的改进,较大地改善了萃取-火焰原子吸收分光光度法测定银、镉和铊的稳定性和灵敏度。选择萃取酸度为1.2mol/L HCl、水相和有机相体积配比为3:1~4:1,方法精密度(RSD,n=12)为Ag4.5%~9.6%、Cd1.5%~7.9%、T14.5%~5.4%,检出限(3s)为Ag0.004μg/g、Cd0.007μg/g、T10.011μg/g,符合多目标地球化学调查样品测试及质量监控要求。用国家一级标准物质和密码组合标准物质进行验证,测试结果令人满意。  相似文献   

7.
用硝基苯萃取[Cd(Phen)3]^2+I2^-离子对,再用盐酸反萃取,利用氢化物发生-原子荧光光谱法测定镉的含量,从而间接测定碘。实验在pH=5.2的NaAc-HAc缓冲体系下进行,优化了还原剂KBH;中邻菲罗啉的浓度,镉溶液用量,萃取剂硝基苯的用量,反萃取盐酸的酸度,并制备碘的标准曲线,其线性相关系数R2≥0.9942,线性范围0~10ng/mL,精密度为8.5%,检出限0.80ng/mL,利用标准曲线测出水样中碘的浓度为17.78ng/mL,结果令人满意。实验表明,开发原子荧光光谱间接分析方法,使其能够准确测量更多种类的元素,有着十分积极的意义,同时也能够促进该方法得到更广范的应用。  相似文献   

8.
陈志兵 《岩矿测试》2002,21(4):311-314
土壤样品经王水分解,转化成HCl溶液,再用NaOH溶液调至碱性,样品溶液首先与KBH4混合,然后与酸作用完成氢化物发生,用原子荧光光谱法测定样品中的痕量硒。方法检出限为0.01μg/g。线性范围为1-200μg/L,样品中硒的含量为0.082μg/g和0.34μg/g时,RSD(n=12)分别为4.9%和2.9%。方法经土壤国家一级标准物质中硒的测定验证,结果与标准值相符。  相似文献   

9.
李刚  曹小燕 《岩矿测试》2008,27(3):197-200
采用HF-HClO4-HNO3分解样品,8 mol/L HNO3提取剂,外标法校准,电感耦合等离子体质谱法同时测定地球化学样品中锗和镉。选择103Rh为内标,确定了最佳仪器参数,研究了Zn、Zr、Sn、Ce、Nd、Sm对Ge和Cd的干扰,试验选择质量数74Ge和114Cd作为测定同位素,采用数学公式校正法校正了来自Nd和Sm的二次电离离子对Ge的干扰、Sn对Cd的同质异位素干扰。方法检出限(10s)分别为Ge 30 ng/L、Cd 15 ng/L,精密度(RSD,n=15)为Ge 1.35%、Cd 1.47%。对多种国家一级标准物质进行分析验证,结果与标准值相符。方法适用于地质样品中微量锗和镉的测定。  相似文献   

10.
氢化物—原子荧光法测定岩石中痕量硒的干扰及消除   总被引:12,自引:10,他引:12  
张锦茂  范凡 《岩矿测试》1993,12(4):264-267
用HF-HClO4-HNO3混合酸分解样品,采用Fe^3+作释放剂,研究了不同量的Fe^3+与HCl酸度对Se荧光强度的影响和干扰离子消除的效果,以及Fe^3+存在Te存在下对Se测定的影响。方法的检出限为0.01μg/g.样品中Se量为0.1μg/g的相对标准偏差(n=11)是5.4%。用于岩石标样中痕量Se的测定,结果较好。  相似文献   

11.
Generation of Deccan Trap magmas   总被引:1,自引:0,他引:1  
Deccan Trap magmas may have erupted through multiple centers, the most prominent of which may have been a shield volcano-like structure in the Western Ghats area. The lavas are predominantly tholeiitic; alkalic mafic lavas and carbonatites are rare. Radioisotope dating, magnetic chronology, and age constraints from paleontology indicate that although the eruption started some 68 Ma, the bulk of lavas erupted at around 65–66 Ma. Paleomagnetic constraints indicate an uncertainty of ± 500,000 years for peak volcanic activity at 65 m.y. in the type section of the Western Ghats. Maximum magma residence times were calculated in this study based on growth rates of “giant plagioclase” crystals in lavas that marked the end phase of volcanic activity of different magma chambers. These calculations suggest that the > 1.7 km thick Western Ghats section might have erupted within a much shorter time interval of ∼ 55,000 years, implying phenomenal eruption rates that are orders of magnitude larger than any present-day eruption rate from any tectonic environment. Other significant observations/conclusions are as follows: (1) Deccan lavas can be grouped into stratigraphic subdivisions based on their geochemistry; (2) While some formations are relatively uncontaminated others are strongly contaminated by the continental crust; (3) Deccan magmas were produced by 15–30% melting of a Fe-rich lherzolitic source at ∼ 3–2 GPa; (4) Parent magmas of the relatively uncontaminated Ambenali formation had a primitive composition with 16%MgO, 47%SiO2; (5) Deccan magmas were generated much deeper and by significantly more melting than other continental flood basalt provinces; (6) The erupted Deccan tholeiitic lavas underwent fractionation and magma mixing at ∼ 0.2 GPa. The composition and origin of the crust and crust/mantle boundary beneath the Deccan are discussed with respect to the influence of Deccan magmatic episode.  相似文献   

12.
Generation of Mid-ocean Ridge Tholeiites   总被引:11,自引:10,他引:1  
If a basaltic magma is separated from its mantle source regiononly after a large amount of fusion, as indicated for mid-oceanridge tholeiites by large ion lithophile (LIL) element studies,volatile-free phase relationships may be used to model closelythe fusion process at the site of origin. Volatile-free soliduscurves in pressure-temperature space display low-temperaturecusps where subsolidus phase transitions intersect the solidus,and these cusps are believed to be important in controllingthe depth of magma generation and the compositions of primarymagmas. In the system CaO-MgO-Al2O3-SiO2, the solidus curvefor simplified plagioclase and spinel lherzolite has been determinedup to 20 kb, and a cusp has been found at 9 kb, 1300 °C,where the transition from simplified plagioclase to spinel lherzoliteintersects the solidus and forms an invariant point. Simplifiedbasaltic melts formed along the solidus curve change from quartz-normativecompositions at low pressures to olivine-normative compositionsat high pressures, and the composition of the first liquid producedat the 9 kb cusp resembles closely the composition of the least-fractionatedmid-ocean ridge tholeiites. It is proposed that these least-fractionatedbasalts have been modified very little by fractional crystallizationas they passed upward to the surface and are close to the compositionof primary basalt generated at the mantle equivalent of the9 kb cusp (30 km depth). Assuming a lherzolitic mantle source,the composition of this primary magma would be expected to remainfairly constant despite varying amounts of fusion as long asthese amounts are between about 2 and 35 per cent, and despitevariations in the proportions of minerals in the source region.For complex natural compositions in the mantle, the cusp wouldnot be a point but would be expected to appear as a low temperatureregion on the solidus extending over a small pressure rangeat about 9 kb and 1200–1250 °C. It is suggested thatmagma generation at the cusp causes a sharp change in the slopeof the geotherm beneath active ridges from approximately adiabaticat depths geater than about 30 km to strongly superadiabaticat depths less than 30 km. LIL element concentrations indicatethat a close approach to fractional fusion is not applicableto the generation of primary magmas at spreading centers. Instead,a model involving varying amounts of equilibrium fusion is preferred,with fresh mantle being continually supplied at the 9 kb cuspas mantle material convects upward along the rising limb ofa mantle convection cell. Primary magmas would thus be producedwith fairly uniform major element compositions but widely differentLIL element concentrations. Subsequent fractional crystallizationof the primary magmas would produce most of the observed majorelement variations in the erupted basalts but would have onlya second-order effect on the LIL element concentrations.  相似文献   

13.
This paper presents the results of a comprehensive experimental study of the formation of granitoid melts at the expense of olivine-normative amphibolites. It was shown that trondhjemite-tonalite and granite-granodiorite melts can be generated by incongruent melting reactions at pressures of 5–25 kbar at T = 800–1000°C. The compositions of coexisting phases and phase reactions were investigated in detail. It was found that interaction between these hydrous melts and the overlying peridotite material results in the metasomatic alteration of peridotites and formation of andesite melts. The granitization of amphibolite was explored. Infiltration granitization was experimentally reproduced for the first time at T = 750°C and P f = 5 kbar. Fluid percolation through amphibolite produced a column of feldspathized and debasified rocks and granite melt completely replacing amphibolite in the proximal zone. Another extreme type of granitization occurring in amphibolite at the contact with granite melt was investigated at T = 800–950°C and P f = 7 kbar. The diffusion of silica and alkalis resulted in the metasomatic alteration of amphibolite and formation of granitic droplets and lenses with the development of migmatite-like zones, which significantly differ in composition and structure from the zones of infiltration granitization. All the models addressed in this paper (derivation of granitoid series, interaction of granitoid melts with peridotites, and infiltration and diffusion granitization) provide insight into the mechanism of formation of many natural objects.  相似文献   

14.
吴信才  徐世武  万波  吴亮 《地球科学》2014,39(2):221-226
随着云GIS理念的提出及深化, 继局部网软件的C/S结构、互联网软件的B/S结构之后, 提出新一代适合云计算、云服务的软件结构——T-C-V结构(terminal-cloud-virtual), 并从基本概念、总体结构及核心技术等方面对其进行了详细阐述.在该结构中, V层基于底层的虚拟化软硬件设备, 屏蔽不同计算机、不同网络、不同存储设备的异构特性, 为上层应用提供统一高效的运行环境; C层是海量地理信息数据、服务和资源管理与服务体系框架; T层面向政府、企业、公众等信息使用者, 提供标准访问接口, 搭建各类终端应用.可以说, T-C-V结构将改变地理信息服务模式、计算模式和商业模式, 可以更好的交互、更加透明化的创建面向大众和企业的应用.   相似文献   

15.
横波激发新技术   总被引:5,自引:0,他引:5  
横波地震是深入认识沉积岩性、岩相的具有发展前途的崭新方法和手段。根据国外资料,对横波激发新技术中的三孔法、水平重锤法、SHOVER法与横波振动器作了介绍与比较。  相似文献   

16.
17.
<正> 二次生烃作用是指烃源岩在地质历史过程中所受温度降低以后,导致生烃作用(一次生烃作用)停止,当所受温度再次升高,并达到合适的热动力学条件时,烃源岩再次生烃的过程。张有生等所做的热模拟实验结果表明,烃源岩二次生烃的演化轨迹不同于一次连续演化生烃,也不是沿着一次生烃的演化轨迹继续进行下去的,它有特定的规律性,主要体现在以下几个方面。(1)二次生烃高峰具有迟滞性。模拟结果表明,在沉积初始成熟度 R_o 小于2.0%以前,二次生烃存在一个生烃高峰,而且,初始成熟度在生烃高峰  相似文献   

18.
本文结合厦门海沧经济开发区路网规划工作,着重探讨了区域公路网规划的分区、原则、交通量预测、路网布局、实施方案等问题。  相似文献   

19.
A geotechnical problem that involves several spatially correlated parameters can be best described using multivariate cross-correlated random fields. The joint distribution of these random variables cannot be uniquely defined using their marginal distributions and correlation coefficients alone. This paper presents a generic methodology for generating multivariate cross-correlated random fields. The joint distribution is rigorously established using a copula function that describes the dependence structure among the individual variables. The cross-correlated random fields are generated through Cholesky decomposition and conditional sampling based on the joint distribution. The random fields are verified regarding the anisotropic scales of fluctuation and copula parameters.  相似文献   

20.
Fluorine-bearing fluids can be generated by breakdown of PdF2 in hydrothermal experiments. This promising technique allows addition of a fixed amount of F without affecting the composition of the rest of the system. The method is simpler, more flexible and potentially yields better results than most other techniques of F addition. Melting and crystallization experiments using natural starting materials are particularly well suited to application of this method.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号