X射线荧光光谱法测定红土镍矿中多种元素

分别研究了采用压片、熔片两种制样方法,用X射线荧光光谱法(XRF)测定了红土镍矿中的9种元素。压片法重点研究了基体效应校正,经散射线作内标和经验系数法校正后,可准确测定除二氧化硅、氧化镁外的7种元素,方法简便、快速;而熔片法着重研究了熔剂和熔样温度的选择,经基体效应校正,各分析元素的结果准确度完全可与化学法相媲美,其相对标准偏差(RSD)在0.50%～3.00%间。     

Analyse quantitative des hydrocarbures aromatiques polynucleaires par spectrofluorimetrie shpol'skii a 10 k: utilisation de la raie de mercure excitatrice diffusee par la matrice comme intensite lumineuse de reference

(Quantitative analysis by Shpol'skii spectrofluorimetry of polynuclear aromatic hydrocarbons at 10 K with the mercury excitation line scattered by the matrix used as a standard intensity.)High-resolution Shpol'skii spectrometry in a matrix is particularly suitable for the determination of trace polynuclear aromatic hydrocarbons in complex mixtures. In the usual technique, the method of standard additions is backed up by internal calibration, which is tedious. A direct calibration technique is proposed in which the mercury excitation line, scattered by the polycrystalline matrix, serves as the standard intensity. Detection limits vary from 0.3 ng ml^?1 for benzo(a)pyrene to 48 ng ml^?1 for pyrene, with linear response over about 2 orders of magnitude. The dynamics and a statistical analysis of the confidence interval for the results are discussed.     

Contributions to accuracy improvement of simultaneous ICP atomic emission spectrometry using multi-line measurements of analyte and internal standard elements Applications for the analysis of permalloy

For successful application of simultaneous ICP atomic emission spectrometry for major component determinations in multi-component materials the accuracy of the method has to be improved. As a contribution to solve this problem a combined procedure for multi-component standard sample preparation, optimum calibration and different variations of internal standard corrections is described. Variance-weighted multi-line calibrations give most accurate results. Internal standard corrections are effective, if the time-dependent spectral line intensity fluctuations of the standard and the analyte elements are well correlated. Their sensitivities against some responsible device parameter variations are investigated. On the basis of multi-line measurements of the analyte and internal standard elements a “group-selected internal standard correction” (GS-ISC) method is applied and results in relative errors of less than 1% even for extreme fluctuations of the raw intensities. For rapid routine determination methods of materials with variable element compositions the added line intensities of the internal standard element can be used to correct the added analyte line raw intensities (“intensity addition internal standard correction” (IA-ISC) method). These accuracy optimization procedures are applied for the analysis of the soft magnetic material permalloy using the internal standard element In.     

Real-time internal standardization with an axially-viewed inductively coupled plasma for optical emission spectrometry

An evaluation of precision improvements using real-time internal standardization with an axially-viewed inductively coupled plasma (ICP) is presented. New findings are presented with respect to the nature of the noise in the analytical signals from the axial ICP. It is observed that a high degree of correlation exists in the line signals from the axial ICP. Using the yttrium ion line at 371.030 nm as the internal standard, the analytical precision after the application of real-time internal standardization is maintained between 0.1 and 0.2% relative standard deviation (RSD) for ion lines. Precision improvement factors of 3 to 4 are obtained by comparison with the uncorrected results. With atomic lines, real-time internal standardization using the yttrium ion line is less effective, yielding precision values between 0.2 and 0.7% RSD. The precision improvement factors for atomic lines are between 1.5 and 3. Thus, real-time internal standardization provides significant improvements in the RSDs of the line signals. The limits of these improvements are explored and an equation is presented which yields the fundamental shot noise limit for precision. Shot noise limited precision is demonstrated. However, this is not possible for all elements using a single internal standard signal. The effectiveness of real-time internal standardization is shown to be dependent on the nature of the specific spectral line. With the axially-viewed ICP, the dominant phenomenon preventing the full benefit of internal standardization from being obtained is the amplitude of the noise in the line signals and not the degree of correlation between analyte and internal standard signals. A trend is observed for atomic transitions in which lower excitation energy is correlated with higher relative noise amplitudes. This finding is in contrast with previously published work on the radially-viewed ICP. An explanation of this result is proposed which takes into account the influence of vaporizing sample droplets in the observation volume.     

X射线荧光光谱法测定黏土中的主次组分

采用熔融玻璃片制样,选用标准样品,以经验α系数和散射线内标法校正元素谱线重叠干扰和基体效应,使用ZSX Primus Ⅱ X射线荧光光谱仪对黏土样品中的Al₂O₃、SiO₂、Fe₂O₃、CaO、MgO、K₂O、Na₂O、MnO、P₂O₅、TiO₂、Cu、Cr等组分进行测定,分析结果与标准值和化学值相吻合,12次测定的相对标准偏差小于10%.     

高压覆膜制样X射线荧光光谱法测定多金属矿中的多种元素

采用新的制样技术——高压(1800 kN)覆膜(3.6μm Polyester Film)制样,波长色散X射线荧光光谱测定多金属矿中19种组分。该制样技术对高硅锌矿石GBW07237(SiO282.95%),不加黏结剂,也能制出理想的样片。测定结果显示1800 kN制备样品多数组分的灵敏度、精密度和检出限较400 kN制备的样品有所改善。15个多金属矿标准物质建立校准曲线,使用Rh Kα的瑞利散射线作内标测定Cu、Pb、Zn、As和Rh Kα的康普顿散射线作内标测定Sb、Ag、Sn、Bi、Mo及经验系数法校正基体效应。Cu、Pb、Zn、Mn、As、Sb、Ag、Sn、Bi、Mo的测定结果与化学法相符,可同时分析其中的Cd、S、Fe、SiO2、Al2O3、MgO、CaO、Na2O、K2O等成分。实现了固体直接进样测定多金属矿中的多种元素。高压覆膜制样技术是制样技术的突破,国内外尚未见报道。     

Determination of several trace elements in silicate rocks by an XRF method with background and matrix corrections

An X-ray fluorescence method for determining trace elements in silicate rock samples was studied. The procedure focused on the application of the pertinent matrix corrections. Either the Compton peak or the reciprocal of the mass absorption coefficient of the sample was used as internal standard for this purpose. X-ray tubes with W or Cr anodes were employed, and the W Lβ and Cr K Compton intensities scattered by the sample were measured. The mass absorption coefficients at both sides of the absorption edge for Fe (1.658 and 1.936 Å) were calculated. The elements Zr, Y, Rb, Zn, Ni, Cr and V were determined in 15 international reference rocks covering wide ranges of concentration. Relative mean errors were in many cases less than 10%.     

A method of locating dried residue on a semiconductor wafer in vapor phase decomposition-total-reflection X-ray fluorescence spectrometry by monitoring scattered X-rays

Vapor phase decomposition-total-reflection X-ray fluorescence spectrometry (VPD-TXRF) is used in the analysis of whole-surface trace metal contamination on silicon wafers at a very high sensitivity. In VPD-TXRF, locating the exact position of dried residue is critical for obtaining a reliable analysis. To locate the residue, the fluorescence from the internal element added as standard reference for quantification is most commonly used as a search marker. However, the added internal standard reference sometimes interferes with the determination of analytes. To avoid such interference, we introduce a new method of locating the residue that utilizes the scattered X-rays from it. Basic experiments have shown that scattered X-rays can be used as markers of residue position instead of the fluorescence from an internal standard reference. An x–y–θ-controlled stage has been proven to be preferable in the application of this locating method than an r–θ-controlled stage. The repeatability of our method is the same as that of the conventional internal standard reference method. There are many advantages in our new method: no interference with analytes of interest, speed, and ease of application. In addition, the method is compatible with the conventional internal standard reference method.     

Determination of trace elements in unfused rock and mineral samples by x-ray fluorescence

The wavelength range in which trace elements are commonly determined by X-ray fluorescence has been divided into three major regions: wavelengths longer than 1.9 Å, between 1.9 and 0.6 Å, and shorter than 0.6 Å. The factors controlling matrix effects differ somewhat in each of these regions; the methods that can be applied to compensate for these effects also differ. The least laborious correction method is the internal standard technique involving scattered X-ray tube spectra. The results are discussed in the light of trace element determinations carried out on geochemical standards.     

X射线荧光光谱法同时快速测定锑矿石中伴生及有害元素

采用粉末压片制样,波长色散型X射线荧光光谱法测定锑矿石中9个次量伴生及有害元素Cu、Pb、Zn、As、Co、Ni、W、Ba、S.选用国家标准物质和人工合成标准参考物质建立校准工作曲线,采用经验系数法和散射线内标法校正基体效应和元素重叠干扰.方法的检出限低、精密度(RSD,n=12)小于5%,测定结果与参考值或化学值一致性良好.与化学法相比,操作简单、快速、准确度高,精密度好,有效解决化学法在锑矿石伴生、有害等微量组分分析中过程烦琐、干扰严重等问题.