X-ray fluorescence wavelength-dispersive

A widely used procedure for determining trace amounts of selenium involves separating selenium from solution by reduction to elemental selenium using tellurium (as a carrier) and hypophosphorous acid as reductant. The precipitated selenium, together with the carrier, are collected by filtration and the filtered soflds examined directly in the wavelength-dispersive x-ray fluorescence spectrometer (70). Numerous spectrophotometric and other methods have been pubHshed for the deterruination of trace amounts of selenium (71—88). 

Wavelength dispersive x-ray fluorescence spectrometric (xrf) methods using the titanium line at 0.2570 nm may be employed for the determination of significant levels of titanium only by carefiil matrix-matching. However, xrf methods can also be used for semiquantitative determination of titanium in a variety of products, eg, plastics. Xrf is also widely used for the determination of minor components, such as those present in the surface coating, in titanium dioxide pigments. 

FCC feedstocks contain sulfur in the form of organic-sulfur compounds such as mercaptan, sulfide, and thiophenes. Frequently, as the residue content of crude oil increases, so does the sulfur content (Table 2-5). Total sulfur in FCC feed is determined by the wavelength dispersive x-ray fluorescence spectrometry method (ASTM D-2622), The results are expressed as elemental sulfur. 

Taggart JE Jr, Lindsay JR, Scott BA, Vivit DV, Bartel AJ, Stewart K C (1993) Analysis of geological materials by wavelength-dispersive X-ray fluorescence spectrometry. In Badecker PA, ed. U.S. Geological Survey Bulletin 1770. Methods for Geochemical Analysis, pp E1-E19. 

Table 8.38 Main features of wavelength-dispersive X-ray fluorescence spectrometry (WDXRF)...

Falcone, R., A. Renier, and M. Verita, M. (2002), Wavelength-dispersive X-ray fluorescence analysis of ancient glasses, Archaeometry 44(4), 531-542. 

Wavelength dispersive X-ray fluorescence spectrometric (xrf) methods, 25 60 Wavelength dispersive spectrometer (WDS), 76 488, 26 433-434 Wavelength dispersive X-ray fluorescence (WDXRF)... 

This non-destructive technique is a very suitable tool for rapid in-line analysis of inorganic additives in food products (Price and Major, 1990 Anon, 1995). It can be readily used by non-skilled operators, and dry materials can be pressed into a pellet or simply poured into a sample cup. The principles of this technique related to food analysis are described by Pomeranz and Meloan (1994). A useful Internet site is http //www.xraysite.com, which includes information about different XRF instruments from various companies. Wavelength dispersive X-ray fluorescence (WD-XRF) or bench-top energy dispersive (ED-XRF) instruments are available. XRF is a comparative technique, thus a calibration curve needs to be established using food products of the same type as those to be... 

D 4927 Elemental Analysis of Lubricant and Additive Components, Barium, Calcium, Phosphorus, Sulfur, and Zinc, by Wavelength Dispersive X-ray Fluorescence Spectroscopy... 

X-ray spectroscopy is nowadays applied mostly in the form of X-ray fluorescence, where scanning monochannel machines, sequence spectrometers and simultaneous spectrometers are used in wavelength dispersive X-ray fluorescence. The introduction of bent analyser-crystals extended the method to smaller samples, thus marking another step toward microprobe analysis. 

The determination of the compositions was carried out using a Philips PW 1480 wavelength dispersive X-ray fluorescence (XRF) spectrometer. All the chemical elements were analysed using a side window Sc-Mo target X-ray tube and under a vacuum path. 

The BET surface areas of the zeolite samples were determined by N2 adsorption-desorption at -196 C in a Micromeritics ASAP 2010 equipment. The adsorption data were treated with the full BET equation. The t-plot method was applied in order to obtain an estimation of the micropore volume. The determination of the compositions was carried out using a Philips PW 1480 wavelength dispersive X-ray fluorescence (XRF) spectrometer. The crystallinity and the unit cell size were established by a Philips PW 1710 X-ray diffractometer (XRD) with CuKa radiation (A.=1.5406A) and Ni filter. 

Nickel and vanadium along with iron and sodium (from the brine) are the major metallic constituents of crude oil. These metals can be determined by atomic absorption spectrophotometric methods (ASTM D-5863, IP 285, IP 288, IP 465), wavelength-dispersive X-ray fluorescence spectrometry (IP 433), and inductively coupled plasma emission spectrometry (ICPES). Several other analytical methods are available for the routine determination of trace elements in crude oU, some of which allow direct aspiration of the samples (diluted in a solvent) instead of time-consuming sample preparation procedures such as wet ashing (acid decomposition) or flame or dry ashing (removal of volatile/combustible constituents) (ASTM D-5863). Among the techniques used for trace element determinations are conductivity (IP 265), flameless and flame atomic absorption (AA) spectropho-... 

Selected neat-theoretical density samples were hot isostatically pressed to full density (1400°C, 180 MPa, 1 h). Compact purity at this stage of processing was assessed using wavelength-dispersive x-ray fluorescence a detection limit of <1 ppm for the impurities of interest is claimed. No loss of purity relative to the starting powder was detected for the undoped material. Chemical analysis of the Ti-doped material indicated a Ti level of =700 ppm, with a factor of two uncertainty. This su ests no substantial Ti loss occurs during firing. 

There are about 20 laboratory based ASTM standard test methods available for the determination of sulfur in various petroleum products and lubricant samples [6]. These utilize diverse analytical techniques and have applicability range sparming from m% to low mg/kg levels. However, at the very low end of sulfur analysis there are only three or four test methods which can adequately determine sulfur in such fuels. These lab-based standard test methods include ASTM D 2622 - wavelength dispersive X-ray fluorescence, D 3120 - oxidative microcoulometry, D 5453 - combustion UV-fluorescence, and D 6920 - oxidative combustion electrochemical detection methods. Without a doubt, the most widely used two methods out of these in oil industry laboratories are D 2622 and D 5453. Studies have shown that at truly ultra-low levels of sulfur only D 5453 can deliver accurate and precise results. This conclusion has... 

Maltenes, 51 Mercury, 181, 196, 207 volatile, 181 Microflow nebulizer, 51 Microwave digestion, 33 Monochromatic wavelength dispersive x-ray fluorescence, 116... 

Jenkins R. Wavelength-dispersive X-ray Fluorescence Analysis, in Encyclopedia of Analytical Chemistry, ed. R.A. Meyers, John Wiley Sons, Chichester 2000, 13422-13444. 

Potts P. Wavelength-dispersive X-ray Fluorescence, in Encylopedia of Aruily-tical Science, ed. A. Townshend, Academic Press, London 1995, Vol. 9, 5611-5622. 

The production laboratory at the Herculaneum smelter performs quality analytical work for all the processes. The laboratory equipment includes a spark emission spectrophotometer, inductively coupled plasma atomic emission spectrometer, wavelength dispersive X-ray fluorescence spectrometer, sulfur analysis equipment, and wet chemistry equipment. The laboratory conducts the analysis for all process materials, including sinter, blast furnace slag, lead bullion, all finished lead products, and environmental samples. 

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