Multielement analysis of unweighed oil samples by x-ray fluorescence spectrometry with two excitation sources

Sanders, Ronald W.; Olsen, K.B.; Weimer, W.C.; Nielson, K.K.

doi:10.1021/ac00262a018

Cited by 23 publications

(8 citation statements)

References 6 publications

(8 reference statements)

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“…The energy dispersive XRF used a combination of titanium and zirconium excitation sources . A dual-spectrum backscatter parameter matrix correction method was used in the analyses to provide increased sensitivities over a wider range of elements (Sanders et al 1983). With this dual source system, the suite of elements measured extended from aluminum to strontium (excluding germanium, scandium, and the noble gases) and also included mercury and lead.…”

Section: Elemental Analysismentioning

confidence: 99%

Low-temperature conversion of high-moisture biomass: Topical report, January 1984--January 1988

Sealock¹,

Elliott²,

Butner³

et al. 1988

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Pacific Northwest Laboratory (PNL) is developing a low-temperature, catalytic process that converts high-moisture biomass feedstocks and other wet organic substances to useful gaseous and liquid fuels. The advantage of this • process is that it works without the need for drying or dewatering the feedstock. Conventional thermal gasification processes, which require temperatures above 750'C and air or oxygen for combustion to supply reaction heat, generally cannot utilize feedstocks with moisture contents above 50 wt%, as the conversion efficiency is greatly reduced as a result of the drying step. For this reason, anaerobic digestion or other bioconversion processes traditionally have been used for gasification of high-moisture feedstocks. However, these processes suffer from slow reaction rates and incomplete carbon conversion. • The PNL high-moisture gasification system, in which thermocatalytic conversion takes place in an aqueous environment, was designed to overcome the problems usually encountered with high-water-content feedstocks. The process uses a reduced nickel catalyst at temperatures as low as 3Sooc and pressures ranging from 2000 to 4000 psig-conditions favoring the formation of methane gas rather than hydrogen and carbon oxides. Tests have produced gases containing up to 55% methane. By comparison, gases produced by conventional thermal gasifiers typically contain only 5% to 15% methane. When compared with anaerobic digestion, the PNL-produced gases contain similar amounts of methane, but the reaction rate is 300 to 400 times faster. Furthermore, carbon conversion is nearly complete, whereas with anaerobic digestion it is only about 50% to 80%. Over 180 tests have been conducted to evaluate the effectiveness of the process on feedstocks defined as high-moisture biomass. These tests also included 11 experiments at liquefaction conditions to determine oil product compositions and yields. All experiments were conducted batchwise in a 1-L, bolted-closure, highpressure autoclave (reactor), with a magnetically coupled stirrer. The reactor and associated sample lines were made of stainless steel to minimize i i i corrosion. The entire system, except for certain valves and the instrumentation, was housed in a 0.25-in.-thick plate steel barricade. Many other safety features were built into the system, including remotely controlled monitoring and sampling procedures.

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Section: Elemental Analysismentioning

confidence: 99%

Low-temperature conversion of high-moisture biomass: Topical report, January 1984--January 1988

Sealock¹,

Elliott²,

Butner³

et al. 1988

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“…The samples were analyzed with a Kevex spectrometer, model 810a, using Zr and Ag secondary sources. The procedure followed was that described by Sanders et al (1983).…”

Section: Characterization Of Sample Componentsmentioning

confidence: 99%

Photodegradation of mutagens in solvent-refined coal liquids

Kalkwarf¹,

Stewart²,

Pelroy³

et al. 1984

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SUMMARYThe purpose of this investigation was to evaluate any changes in the chemical composition and microbial mutagenicities of two representative solventrefined coal (SRC) liquids as a function of exposure time to sunlight and air. This information was desired to assess potential health hazards arising from ground spills of these liquids during production, transport and use. Results of microbial mutagenicity assays using Salmonella typhimurium TA98, conducted after exposure, showed that the mutagenicities of both an SRC-II fuel oil blend and an SRC-1 process solvent decreased continuously with exposure time to air and that the decrease was accelerated by simultaneous exposure to simulated sunlight. The liquids were exposed as thin layers supported on surfaces of glass, paper, clay or aluminum; but the type of support had little effect on the results. The contrast between these results and the reported increases of mutagenesis in organisms exposed simultaneously to coal liquids and nearultraviolet light suggested that short-lived mutagenic intermediates, e.g., organic free radicals, were formed in the liquids during exposure to light.The highest activities of microbial mutagenicity in the SRC liquids were found in fractions rich in amino polycyclic aromatic hydrocarbons (amino PAH). After a 36-hour exposure of the fuel oil blend to air in the dark, the mutagenicity of its amine-rich fraction was reduced by 65%; whereas a 36-hour exposure in the light reduced the mutagenicity of this fraction by 92%. Similar rates of reduction in mutagenicity were achieved in exposures of the process solvent. The mutagenicities of other chemical fractions remained low during exposure. Analyses showed that most of the amine components of both liquids contained less than four aromatic rings and that their concentrations generally decreased with exposure time. These results indicate that the microbial mutagenicities of the two SRC liquids may be expected to gradually decrease if they are spilled out of doors, with the rate of decrease dependent on their access to air and sunlight. However, one cannot be sure that all of the potential health hazards of these materials are reduced by such exposures si nee the _i. typhimurium TA98 test system has been reported to be relatively insensitive to potential mutagens in fractions of SRC liquids rich in neutral aromatic compounds.Electron spin resonance (ESR) measurements on the liquids showed free radical concentrations on the order of 5xlo 16 unpaired spins per gram before exposure. In darkness, this concentration decreased continuously during exposure to air, paralleling the decrease in mutagenicities of the samples. In simulated sunlight, the concentration of paramagnetic species rapidly increased within the first few minutes of illumination and then decreased with continued exposure. This behavior suggested that organic free radicals were the major paramagnetic species, although charge-transfer complexes may have also been present. The ESR spectra were not sufficiently resolved to identi...

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“…A comprehensive review of studies based on the use of the Compton scattering, especially for monochromatic (secondary and radioactive) sources, is given by Nielson [43]. A detailed analyses for matrix absorption and scattering effects for fundamental parameter (FP) analysis of a variety of materials from low Z substrates such as petroleum to plant, mineral, and metal substrates using single (Zr) [44] and double (Zr and Ti) secondary X-ray sources [45] is described by Nielsen using an iterative analysis procedure [35].…”

Section: Fundamental Parameters Analysismentioning

confidence: 99%

High Definition X‐Ray Fluorescence: Principles and Techniques

Chen¹,

Gibson²,

Huang³

2008

X-Ray Optics and Instrumentation

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Energy dispersive X-ray fluorescence (EDXRF) is a well-established and powerful tool for nondestructive elemental analysis of virtually any material. It is widely used for environmental, industrial, pharmaceutical, forensic, and scientific research applications to measure the concentration of elemental constituents or contaminants. The fluorescing atoms can be excited by energetic electrons, ions, or photons. A particular EDXRF method, monochromatic microfocus X-ray fluorescence (MμEDXRF), has proven to be remarkably powerful in measurement of trace element concentrations and distributions in a large variety of important medical, environmental, and industrial applications. When used with state-of-the-art doubly curved crystal (DCC) X-ray optics, this technique enables high-sensitivity, compact, low-power, safe, reliable, and rugged analyzers for insitu, online measurements in industrial process, clinical, and field settings. This new optic-enabled MμEDXRF technique, called high definition X-ray fluorescence (HD XRF), is described in this paper.

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Multielement analysis of unweighed oil samples by x-ray fluorescence spectrometry with two excitation sources

Cited by 23 publications

References 6 publications

Low-temperature conversion of high-moisture biomass: Topical report, January 1984--January 1988

Low-temperature conversion of high-moisture biomass: Topical report, January 1984--January 1988

Photodegradation of mutagens in solvent-refined coal liquids

High Definition X‐Ray Fluorescence: Principles and Techniques

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