X-ray spectrometric determination of major elements in silicate rock samples, using a thin film technique based on ion exchange dissolution

1973 ◽  
Vol 2 (2) ◽  
pp. 57-62 ◽  
Author(s):  
K. Govindaraju
1980 ◽  
Vol 63 (4) ◽  
pp. 709-712
Author(s):  
Henry B S Conacher ◽  
Rajinder K Chadha ◽  
Gladys Lacroix

Abstract Three sample preparation techniques—thin-film, solution, and cellulose pellet—were applied to the determination of bromide in brominated lipids by X-ray fluorescence spectroscopy. Using brominated vegetable oils of known bromide content it was demonstrated that the thin-film technique could result in erroneously high bromide contents, which could also vary with the amount of oil applied, depending on the solvent used. As solutions in hexane, slightly high bromide contents were observed at high concentrations. With the cellulose pellets, bromide contents similar to known values were observed. It was concluded that the cellulose pellet procedure, although more time consuming, and less convenient for ready recovery of sample, was the most suitable for organic bromide determination. Similar results were indicated for chlorinated oils.


Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.


Author(s):  
J N Chapman ◽  
W A P Nicholson

Energy dispersive x-ray microanalysis (EDX) is widely used for the quantitative determination of local composition in thin film specimens. Extraction of quantitative data is usually accomplished by relating the ratio of the number of atoms of two species A and B in the volume excited by the electron beam (nA/nB) to the corresponding ratio of detected characteristic photons (NA/NB) through the use of a k-factor. This leads to an expression of the form nA/nB = kAB NA/NB where kAB is a measure of the relative efficiency with which x-rays are generated and detected from the two species.Errors in thin film x-ray quantification can arise from uncertainties in both NA/NB and kAB. In addition to the inevitable statistical errors, particularly severe problems arise in accurately determining the former if (i) mass loss occurs during spectrum acquisition so that the composition changes as irradiation proceeds, (ii) the characteristic peak from one of the minority components of interest is overlapped by the much larger peak from a majority component, (iii) the measured ratio varies significantly with specimen thickness as a result of electron channeling, or (iv) varying absorption corrections are required due to photons generated at different points having to traverse different path lengths through specimens of irregular and unknown topography on their way to the detector.


1989 ◽  
Vol 33 ◽  
pp. 521-529
Author(s):  
Tomoya Arai ◽  
Takashi Shoji

In the spectroscopic analysis of composite elements by x-ray fluorescence (XRF), it is the fundamental feature of this method that the background x-ray intensity is lower than that with electron excitation. However, the background x-rays of this method, which consist of Thomson (Rayleigh) and Compton scattered x-rays from the primary radiation, impair the analytical performance at the ppm level. In order toinvestigate the intensity of the background x-rays precisely,the study was conducted in two parts. The first part compared the measured and theoretically calculated x-ray intensities for Rh Kα and Rh Kβ peaks from various materials. The second part examined the determination of low concentrations of lead,arsenic and colonium in steel samples. The variation in the background x-ray intensities of the analyzed elements was found to be caused by the variation of the major elements and a correction equation for it is derived.


1998 ◽  
Vol 84 (3) ◽  
pp. 1703-1705 ◽  
Author(s):  
A. Kazimirov ◽  
G. Scherb ◽  
J. Zegenhagen ◽  
T.-L. Lee ◽  
M. J. Bedzyk ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document