X-射线荧光光谱法(XRF)测定钼精矿中多种元素

详细论述了压片法及熔融片法测定钼精矿的分析条件。其中压片法通过大量采用同一矿区的生产样品经化学定值后作为校准样品建立校准曲线,因此粒度效应和矿物效应基本上可忽略。详细地讨论了元素之间谱线干扰、背景和脉冲高度选择。使用经验系数法校正基体效应,可准确测定钼精矿中的钼、硫、铁、铜、铅、锌等11种元素。在熔融片法中主要讨论了元素谱线的选择及其相互之间的干扰,经理论α系数校正后,可准确测定不同钼矿中的多种元素,其适用范围更广。     

X-射线荧光光谱法测定白云石中主次量组分

采用粉末压片x-射线荧光光谱法测定白云石中氧化镁、氧化钙、二氧化硅、三氧化二铝、三氧化二铁和二氧化钛含量。采用校正曲线和基体校准一体的回归方程进行谱线重叠干扰校正和基体效应校正。将白云石样品进行磨细处理,在压片机上制成样片,直接在X-射线荧光光谱仪上按照选定的分析条件,以标准样品做工作曲线,利用工作曲线测定样品含量。通过与国家标准化学法以及熔片法对照,分析结果与标准值、熔片法结果吻合,主含量元素测定结果相对误差不超过10％,同一样品12次测定结果相对标准偏差不超过10％。该方法简便、快速、准确、重现性好。     

XRF准确测定钼精矿中多种元素分析方法研究

本文详细论述了压片法及熔融片法测定钼精矿的分析条件。其中压片法通过大量采用同一矿区的生产样品经化学定值后作为校准样品建立校准曲线,因此粒度效应和矿物效应基本上可可忽视。文章详细地讨论了元素之间谱线干扰、背景和脉冲高度选择。使用经验系数法校正基体效应,可准确测定钼精矿中的钼、硫、铁、铜、铅、锌等11个元素。在熔融片法主要讨论了元素谱线的选择及其相互之间的干扰。     

经验系数法X射线荧光光谱测定硅酸盐中微量元素

利用粉末样品直接压片,以峰背(包括X光管靶线的康普顿散射线)比法校正基体效应,X射线荧光光谱测定硅酸盐中微量元素,方法简便快速,检出限通常可达到数个ppm。然而,若单纯采用峰背比法校正基体效应,硅酸盐样品中主元素铁的含量在较大范围内变化时,会造成较大的测定误差。本文在峰背比法的基础上,同时采用经验系数法校正由铁含量变化造成的基体及背景的影响,提高了方法的准确度。     

X-射线荧光光谱法测定锆矿石中锆硅铁钛铝钙

采用熔片法制样,建立了X-射线荧光测定锆矿石中锆、硅、铁、钛、铝、钙的分析方法。使用国家一级标准物质与二氧化锆混合配制的混合标准物质,解决了锆矿石标准物质不足的问题。试样:硼酸锂混合熔剂为1:20,在熔样机中熔成玻璃片,采用经验系数法和散射线内标法校正元素间的谱线重叠效应和基体效应,对标准物质和混配的标准样品进行了分析,标准物质测定结果与推荐值一致,相对标准偏差（RSD%）均小于3.6%。方法能满足高含量锆矿石中主、次量元素的测定。     

X射线荧光光谱法测定锰矿中主元素和微量元素

应用X射线荧光光谱法测定了锰矿中主元素锰、铁、硅、钙和微量元素镁、铝、磷、硫、钛、钾、钠等11种元素.试样用四硼酸锂和碳酸锂混合熔剂融熔制成玻璃状熔片并加入碘化铵溶液作为脱模剂.以17个标准样品并结合6个自制标准样品建立校准工作曲线,用理论a系数校正基体效应.对该方法的精密度进行了考核,结果表明以上11种元素测定结果的相对标准偏差均小于4%.用3种标准样品对该方法的准确度进行验证,测定值与标准值相吻合.     

地质试样中多种痕量元素的X射线荧光光谱分析

本文采用粉末压片的制样方法直接测定地质试样中26个痕量元素。采用散射内标及影响系数相结合的方法校正基体效应,方法操作简便,结果准确,可用于常规分析和化探测试工作.     

X射线荧光光谱法测定石油焦中主量元素硫和痕量元素的含量

提出了粉末压片制样-X射线荧光光谱法测定石油焦样品中硫、钠、镁、铝、硅、磷、氯、钾、钙、钡、钛、钒、铬、锰、铁、镍、铜和锌等18种元素含量的方法。将粒径小于0.076mm的石油焦粉末经105℃烘干后置于模具中,以160MPa压力制成厚度小于4mm的样品。以经验系数法和康普顿散射线内标法校正基体效应和元素间的谱线重叠干扰。对石油焦样品连续11次测定,各元素测定值的相对标准偏差均小于8%。方法用于标准样品的分析,测定结果与认定值相符。     

X射线荧光光谱法测定煤灰成分的改进

样品以四硼酸锂和偏硼酸锂为熔剂,硝酸铵为氧化剂,溴化锂为脱模剂,采用玻璃状熔片法制样。选用标准样品及其标准样品间相混合配制的混合样品制作工作曲线,并以α系数和经验系数法校正元素谱线干扰和基体效应,用X射线荧光光谱法对煤灰中的二氧化硅、氧化铝、氧化铁、氧化钙、氧化镁、五氧化二磷、氧化钾、氧化钠、氧化钛、五氧化二钒、氧化锰和三氧化硫等12种主次组分进行测定。方法分析结果与化学法和电感耦合等离子体原子发射光谱法测定值相符;对同一样品按所建方法分别熔融制备10个熔片进行测定,各组分测定值的相对标准偏差(n=10)在0.06%～2.4%之间。     

X射线荧光光谱法分析电解质中氧化铝

采用粉末压片法建立了X射线荧光光谱法测定铝电解质中氧元素含量的方法,通过测定氧元素来计算三氧化二铝的含量;重点讨论了样品前处理、粉料颗粒度、保压时间、压片压力等对于超轻元素的粉末压片制样的影响因素,同时采用二点法对氧元素进行背景扣除,运用固定α系数法校正基体效应;方法的相对标准偏差RSD低于2.00%,方法的检出限为163mg/kg,相对分析误差控制在3%以下,误差控制在电解质中氧化铝质量控制允许的范围之内。方法用来分析铝电解质中氧化铝组分含量,结果准确,符合生产要求。方法简单、快速、灵敏,能够作为铝电解质中氧化铝的有效检测手段。     

Fused glass sample preparation for quantitative laser-induced breakdown spectroscopy of geologic materials

Laser-induced breakdown spectroscopy is a powerful analytical method, but LIBS is subject to a matrix effect which can limit its ability to produce quantitative results in complex materials such as geologic samples. Various methods of sample preparation, calibration, and data processing have been attempted to compensate for the matrix effect and improve LIBS precision. This study focuses on sample preparation by comparing fused glass as a preparation for powdered material to the more commonly used method of pressing powder into pellets for LIBS analysis of major elements in complex geologic materials. Pelletizing powdered material is a common and convenient method for preparing samples but problems with the physical matrix brought on by inconsistencies in the homogeneity, density, and laser absorption, coupled with the chemical matrix problem lead to spectral peak responses that are not always consistent with the absolute concentration of representative elements. Twenty-two mineral and rock samples were analyzed for eight major oxide elements. Samples were prepared under both glass and pellet methods and compared for internal precision and overall accuracy. Fused glass provided a more consistent physical matrix and yielded more reliable peak responses in the LIBS analysis than did the pressed pellet preparation. Statistical comparisons demonstrated that the glass samples expressed stronger separability between different mineral species based on the eight elements than for the pressed pellets and showed better spot-to-spot repeatability. Regression models showed substantially better correlations and predictive ability among the elements for the glass preparation than did those for the pressed pellets.     

Application of RF GDMS for trace element analysis of nonconducting La0.65Sr0.3MnO3 ceramic layers

Radio-frequency glow discharge mass spectrometry (RF GDMS) has been applied to the determination of trace elements in ceramic perovskite layers (La_0.65Sr_0.3MnO₃) using synthetic standards. For the preparation of these standards high-purity powder of the basic material (La_0.65Sr_0.3MnO₃) was doped with trace elements in concentrations from 20 to 500 μg/g and the mixture was pressed to compact samples. The resulting calibration curves and the calculated relative sensitivity factors (RSF) differed only from 0.4 to 2 for different elements. For nearly all elements the standard deviations in the determination of trace elements in La_0.65Sr_0.3MnO₃ were better than 15% and detection limits (using the 3σ-criterion) were below 10 μg/g. Changes of the discharge parameters (RF power, pressure of the discharge gas (Ar) in the RF glow discharge) have no significant influence on the sensitivity to elements.     

X射线荧光光谱法测定灰岩中14种主次量元素

采用X射线荧光光谱法对灰岩中的Ca,Mg,Si,K,Na,Fe,Al,Ti,P,S,Mn,Sr,Ba,Cl等14种元素进行同时测定,采用硼酸镶边垫底的粉末压样法,优化了测量条件。对比较轻的元素,采用经验影响系数法校正基体效应,对于较重的元素,采用理论α影响系数法校正基体效应。分析标准参考物质GBW 07132,各元素的精密度(RSD)为0.1%~5.9%,分析标准参考物质GBW 07130,各元素的测定值与标准值相符,该方法对各元素的测定范围宽、速度快。     

粉末压饼LA-ICP-MS测定土壤样品中微量元素

研究了采用粉末压饼制样LA-ICP-MS测定土壤样品中多元素的分析方法.在土壤样品中事先加入已知含量的In,并以聚四氟乙烯(PTFE)为粘合剂,在200 KN的压力下制备用于激光剥蚀的压饼.详细讨论了粉末压饼样品中元素的均一性及元素相对信号响应.所建立的方法用于土壤标准参考物质固体样品的直接分析,测定值与参考值具有较好的一致性.     

Influence of paint components on photoactivity of P25 titania toward NO abatement

The present work studies the interference of paint components on the photoactivity of P25 photocatalyst toward NO abatement. Paint components are divided in two major groups: powder inorganic components and organic components. Two types of films were prepared, powder pressed films and films made of pseudo-paints, and their photoactivity assessed following approximately standard ISO 22197-1:2007(E). Powder pressed films were obtained by stepwise mixing powder components of the base paint; pseudo-paint films involved mixing the powder components stepwise with families of organic components present in the original photocatalytic paint formulation.It was concluded that the morphology of powder pressed films influences the photoactivity while CaCO₃ and silicates, which are extenders, have a smaller impact on P25 photoactivity compared to pigmentary TiO₂.Pseudo-paint films containing the same proportion of powder components as powder pressed films displayed different transient behaviors but similar steady-state photo-activities, regardless the presence of organic components such as the binder. This was assigned to the photo-erosion of a significant fraction of the organic paint components during the transient period. Therefore, after reaching steady-state, NO photooxidation could proceed freely as if only inorganic paint components were present. An average of ca. 25 wt.% of organic phase erosion was observed but more severe erosion should occur closer to the top of the paint film.     

Laser-induced breakdown spectroscopy for quantitative spectrochemical analysis of geological materials: effects of the matrix and simultaneous determination

A microscopic laser-induced breakdown spectrometer was used to evaluate the analytical matrix effect commonly observed in the analysis of geological materials. Samples were analyzed in either the powder or pressed pellet forms. Calibration curves of a number of iron and aluminum compounds showed a linear relationship between the elemental concentration and peak intensity. A direct determination of elemental content can thus be made from extrapolation on these calibration curves. To investigate matrix effects, synthetic model samples were prepared from various iron and aluminum compounds spiked with SiO₂ and CaCO₃. The addition of these matrices had a pronounced analytical effect on those compounds prepared as pressed pellets. However, results indicated the absence of matrix effects when the samples were presented to the laser as loose powders on tape and results were compared to certified values, indicating the reliability of this approach for accurate analysis, provided the sample particle diameters are greater than ≈100 μm. Finally, the simultaneous analysis of two different elements was demonstrated using powders on tape.     

Quantitative analysis of elements (C, N, O, Al, Si and Fe) in polyamide with wavelength dispersive X-ray fluorescence spectrometry

A wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry combined with calibration curve method was established for simultaneously analyzing low-Z elements (C,N,O) and Al,Si,Fe in polyamide.To investigate the origin of plastic material causing deposition and blocking in instrument engines and pipelines,polyamide 6 (PA 6,an engineering plastic) was chosen as the study object on account of its common use in industry.The sample preparation with pressed powder disk has been developed for determination of six elements in PA 6.Pure Cu metal was used as the matrix and PA 6 was regarded as standard sample for C,N,O elements.PA 6 particles were firstly smashed to uniform powder in liquid nitrogen,and then mixed with inorganic standard powders (Fe2O3,Al2O3,SiO2,and Na 2 SiO 3).The mixture was ground to obtain homogeneous calibration materials for WD-XRF analysis.The quantitative property of the calibration curve method for each element was reliable.The limits of detection (S/N≤3) of C,N,O,Al,Si and Fe using WD-XRF were 249,120,101,6.2,3.3,and 1.8 μg/g,respectively.To confirm the accuracy of the proposed WD-XRF calibration curve method,inductively coupled plasma optical emission spectroscopy (ICP-OES) detection for Al,Si,Fe and elemental analyzer (EA) analysis for C,N,O were utilized.A good correlation of the WD-XRF results with the measurements of ICP-OES and EA was observed.