Analysis x-ray fluorescence

X-ray fluorescence analysis is used for qualitative analysis of water 

In X-ray fluorescence spectrometry, primary X-ray radiation is produced by means of an X-ray tube, exciting the sample located in this beam to emit fluorescence. This secondary radiation is rendered parallel by a collimator and diffracted and reflected by a movable analyzer crystal. The intensity of the radiation is measured in the receiver, e.g. a geiger, proportional or scintillation counter, at a wavelength specific to the element. 

In water analysis, a dry residue of the water sample is most commonly used for X-ray fluorescence analysis. The polychromatic radiation emitted by X-ray tubes excites the heavy elements in the dry residue to emit corresponding radiation. 

This secondary radiation is diffracted in an analyzer crystal, thereby breaking it down into the various wavelengths. By measuring the angle of deflection it is possible to calculate the wavelength of the diffracted radiation. 

Disregarding higher-order reflections only one value of the angle of deflection exists for a given wavelength. The spectra emitted by an element consist of a small number of characteristic lines. If the ionization of the element to be determined takes place in the K shell of the atom, it is mainly the K- (X line that is produced. The K- a line is always accompanied by the weaker K-B line. 

FIGURE 6.6 X-ray fluorescence measuring station with an X-RAY-Fischerscope 

During X-ray fluorescence analysis the sample is irradiated with X-rays. The sample then replies by emitting a secondary X-ray radiation. It is divided into wavelengths using the kind of grating provided by a natural crystal. Even in this case, the jxisi-tions of the lines indicate which elements are present and their intensities the concentrations. 

This technique has been applied to determining the identity of oxygen absorbers in polymers [108] also to determine traces of metals in polymers. 

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Mineral and Chemical Composition. X-ray diffraction is used to determine the mineral composition of an Mg(OH)2 sample. Induced coupled plasma (icp) spectrophotometry is used to measure the atomic concentrations present in a sample. X-ray fluorescence analysis is another comparative instmmental method of determining chemical composition. 

Spectroscopic methods for the deterrnination of impurities in niobium include the older arc and spark emission procedures (53) along with newer inductively coupled plasma source optical emission methods (54). Some work has been done using inductively coupled mass spectroscopy to determine impurities in niobium (55,56). X-ray fluorescence analysis, a widely used method for niobium analysis, is used for routine work by niobium concentrates producers (57,58). Paying careful attention to matrix effects, precision and accuracy of x-ray fluorescence analyses are at least equal to those of the gravimetric and ion-exchange methods. 

At X-ray fluorescence analysis (XRF) of samples of the limited weight is perspective to prepare for specimens as polymeric films on a basis of methylcellulose [1]. By the example of definition of heavy metals in film specimens have studied dependence of intensity of X-ray radiation from their chemical compound, surface density (P ) and the size (D) particles of the powder introduced to polymer. Have theoretically established, that the basic source of an error of results XRF is dependence of intensity (F) analytical lines of determined elements from a specimen. Thus the best account of variations P provides a method of the internal standard at change P from 2 up to 6 mg/sm the coefficient of variation describing an error of definition Mo, Zn, Cu, Co, Fe and Mn in a method of the direct external standard, reaches 40 %, and at use of a method of the internal standard (an element of comparison Ga) value does not exceed 2,2 %. Experiment within the limits of a casual error (V changes from 2,9 up to 7,4 %) has confirmed theoretical conclusions. 

If the colloidal systems are considered as objects of X-ray fluorescence analysis, some special features are to be mentioned. 

The goal of our investigation was to develop the X-ray fluorescence analysis procedure for the determination of heavy metals in the paint-and-lacquer materials. 

The procedure of determination of metals in the thin layer without elimination of the non-volatile organic components for different paints containing inorganic pigments was developed. Several techniques of sampling from paint-and-lacquer materials for X-ray fluorescence analysis were proposed. For the study of nonhomogenity of metal distribution in the thin layer we used additionally the local method of X-ray fluorescence analysis. 

In this work the results of reseai ch common sorbtion-X-Ray-fluorescence analysis of Pb(II), Cd(II), Zn(II) and Mo(VI) with preconcentration on complexing chemical silica gel modified with mercaptane groups and modified with 8-hydroxyquinoline were described. The conditions and limits of determination of the X-Ray-fluorescence method in the thin lawyers ai e discussion. 

FEASIBILITY TO APPLY THE PROCEDURE OF NONDESTRUCTIVE X-RAY FLUORESCENCE ANALYSIS OF PLANTS FOR MILK POWDER EXAMINATION... 

RESULTS OF STUDYING HOT PRESSING ADAPTABILITY FOR NONDESTRUCTIVE X-RAY FLUORESCENCE ANALYSIS... 

RESULTS OF EVALUATING NONDESTRUCTIVE X-RAY FLUORESCENCE ANALYSIS OF DRIED MILK SAMPLES OF LIMITED MASS... 

MODERN STATE AND PROSPECTS OF THE DEVELOPMENT OF X-RAY FLUORESCENCE ANALYSIS IN RUSSIA... 

X-RAY FLUORESCENCE ANALYSIS OE COAL CONCENTRATES USING QUASI-SOLID SPECIMENS... 

Among other methods the X-ray fluorescence analysis (XRF) has some advanlages, namely rapidily, seleclivily, accuracy and an opporlunily of aulomalion. Accuracy of Ihe analysis is caused by qualily of Ihe specimen oblained from analyzed sample. 

Over the last seventeen year s the Analytical center at our Institute amassed the actual material on the application of XRF method to the quantitative determination of some major (Mg, Al, P, S, Cl, K, Ti, Mn, Fe) and trace (V, Cr, Co, Ni, Zn, Rb, Sr, Y, Zr, Nb, Mo, Ba, La, Ce, Pb, Th, U) element contents [1, 2]. This paper presents the specific features of developed techniques for the determination of 25 element contents in different types of rocks using new Biaiker Pioneer automated spectrometer connected to Intel Pentium IV. The special features of X-ray fluorescence analysis application to the determination of analyzed elements in various types of rocks are presented. The softwai e of this new X-ray spectrometer allows to choose optimal calibration equations and the coefficients for accounting for line overlaps by Equant program and to make a mathematic processing of the calibration ai ray of CRMs measured by the Loader program. 

N.V. Polosmak and V.A. Tmnova. An analysis of Pazyryk hair (X-ray fluorescent analysis using synclirotron radiation) //Archaeology, Ethnology Anthnoropology of Eurasia, 1(17) 2004, p. 73-71. 

Dzubay, T. G., "X-Ray Fluorescence Analysis of Environmental Samples.". Ann Arbor Science Publishers, Ann Arbor, MI, 1977. 

In Total Reflection X-Ray Fluorescence Analysis (TXRF), the sutface of a solid specimen is exposed to an X-ray beam in grazing geometry. The angle of incidence is kept below the critical angle for total reflection, which is determined by the electron density in the specimen surface layer, and is on the order of mrad. With total reflection, only a few nm of the surface layer are penetrated by the X rays, and the surface is excited to emit characteristic X-ray fluorescence radiation. The energy spectrum recorded by the detector contains quantitative information about the elemental composition and, especially, the trace impurity content of the surface, e.g., semiconductor wafers. TXRF requires a specular surface of the specimen with regard to the primary X-ray light. 

X-Ray Fluorescence analysis (XRF) is a well-established instrumental technique for quantitative analysis of the composition of solids. It is basically a bulk evaluation method, its analytical depth being determined by the penetration depth of the impinging X-ray radiation and the escape depth of the characteristic fluorescence quanta. Sensitivities in the ppma range are obtained, and the analysis of the emitted radiation is mosdy performed using crystal spectrometers, i.e., by wavelength-dispersive spectroscopy. XRF is applied to a wide range of materials, among them metals, alloys, minerals, and ceramics. 

Vol. 140. Total Reflection X-Ray Fluorescence Analysis. By Reinhold Klockenkamper... 

Bulk compositions of altered andesite. Bulk compositions of altered andesite were obtained by XRF analysis (X-ray fluorescence analysis) (Shikazono et al., 2002). 

We prepared thin film Pt alloy electrodes by Ar-sputtering Pt and the second metal targets simultaneously onto a disk substrate at room temperature (thickness approximately 200 nm). The resulting alloy composition was determined by gravimetry and X-ray fluorescent analysis (EDX). Grazing incidence (i7= 1°) X-ray diffraction patterns of these alloys indicated the formation of a solid solution with a face-centered cubic (fee) crystal stmeture. 

K.H.A. Janssens, F.C.V. Adams and A. Rindby (eds), Microscopic X-Ray Fluorescence Analysis, John Wiley Sons, Ltd, Chichester (2000). 

B. Dziunikowski, Energy Dispersive X-Ray Fluorescence Analysis, Elsevier, Amsterdam (1989). 

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