Semi-Quantitative XRD Analysis of Fly Ash Using Rutile as an Internal Standard

1988 ◽  
Vol 32 ◽  
pp. 569-576 ◽  
Author(s):  
A. Thedchanamoorthy ◽  
G.J. McCarthy
Keyword(s):  
Fly Ash ◽  
Error Analysis ◽  
North American ◽  
Intensity Ratio ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Xrd Analysis ◽  
X Rays ◽  
Fly Ashes ◽  
Crystalline Phases

AbstractXRD analysis of fly ash was quantitated using the Reference Intensity Ratio (RIR) method and rutile (TiO2) as an internal standard. Rutile RIR's for 15 of the crystalline phases commonly observed in North American fly ash were determined. Error analysis on the various steps in quantitation indicated that precision ranged from ±10% of the amount present for phases that diffract x-rays strongly to ±21% for weakly diffracting phases. Limit of detection in the mostly glassy fly ashes ranged from 0.2% for lime, the most strongly diffracting phase, to 3.5% for weakly diffracting mullite. Accuracy evaluated with a simulated fly ash was within the limits established by precision, but in actual fly ash samples, accuracy will be a function of the match between the crystallinity and composition of the analyte and the analyte standard. Overlaps among peaks of some of the important phases require intensity proportioning; for this reason, the method is best described as semi-quantitative.

X-ray Diffraction Analysis of Fly Ash. II. Results

1990 ◽  
Vol 34 ◽  
pp. 387-394 ◽  
Author(s):  
G. J. McCarthy ◽  
J. K. Solem
Keyword(s):  
Fly Ash ◽  
Diffraction Analysis ◽  
Chemical Constituents ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Power Station ◽  
Crystalline Phases ◽  
X Ray ◽  
High Calcium

AbstractA protocol for semi-quantitative XRD analysis of fly ash has been applied to 178 ashes in studies of the typical mineralogy of high-calcium and iow-calcium fly ash, the consistency of fly ash mineralogy from a typical power station, the partitioning of chemical constituents into crystalline phases, and the crystalline phases relevant to the use of fly ash in concrete.

Characterization of North American Lignite Fly Ashes I. Chemical Variation

1987 ◽  
Vol 113 ◽  
Author(s):  
Robert J. Stevenson ◽  
James C. Collier ◽  
John J. Crashell ◽  
Larry R. Quandt
Keyword(s):  
Fly Ash ◽  
North American ◽  
Direct Relationship ◽  
Bulk Sample ◽  
Geographic Region ◽  
Chemical Variation ◽  
Fly Ashes ◽  
Lignite Fly Ash ◽  
Chemical Variability ◽  
The Individual

ABSTRACTThe chemical variation of central North American lignite fly ash can be compared using the major and minor oxide analyses and the distribution pattern of the inter-grain chemistries of the individual fly ash particles. AAS and electron microprobe chemical analysis of nineteen fly ashes have been used to illustrate the variations in bulk sample and individual grain chemistry. This information documents the chemical variability of the lignite fly ashes by geographic region. There is a direct relationship between grains rich in SiO2 and Al2O3 and in the Na2O content of the grains in lignite derived fly ashes. There is also a direct relationship between grains rich in CaP and the MgO and SO3 content of the grains in lignite derived fly ashes.

Quantitative XRD Analysis of Advanced Coal Combustion Solid Residuals by the RIR Method

1992 ◽  
Vol 36 ◽  
pp. 343-353 ◽  
Author(s):  
J.A. Bender ◽  
J.K. Solem ◽  
G.J. McCarthy ◽  
M.C. Oseto ◽  
J.E. Knell
Keyword(s):  
Quantitative Analysis ◽  
Coal Combustion ◽  
Internal Standard ◽  
Xrd Analysis ◽  
Crystalline Phases ◽  
Intensity Ratios ◽  
Integrated Intensities ◽  
Solid Residuals

AbstractReference intensity ratios (RIRs) with zincite (ZnO) as the internal standard have been measured and calculated for key phases in coal combustion solid residuals. Detailed comparisons of measured and calculated corundum RIRs (converted from zincite RIRs), and literature I/Ic values led to the conclusion that for best results, laboratory measured values must be used. Using measured zincite RIRs and standard mixtures of important crystalline phases, a protocol for routine semi-quantitative analysis has been developed. The need to grind under ethanol to minimize decomposition of hydrated phases was demonstrated. An unusual procedure employing mixed peak and integrated intensities in the RIR of one key phase, ettringite (Ca6Al2(SO4)3(OH)12-26H2O), has been adopted for this protocol.

Use of a Database of Chemical, Mineralogical and Physical Properties of North American Fly Ash to Study the Nature of Fly Ashand Its Utilization as a Mineral Admixture in Concrete

1989 ◽  
Vol 178 ◽  
Author(s):  
G. J. Mccarthy ◽  
J. K. SOLEM ◽  
O. E. Manz ◽  
D. J. Hassett
Keyword(s):  
Fly Ash ◽  
North American ◽  
Chemical Constituents ◽  
Mineral Admixture ◽  
Test Results ◽  
Fly Ashes ◽  
Physical Test ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Bulk Chemical

AbstractA database of chemical, mineralogical and physical characteristics of North American fly ashes has been assembled by the Western Fly Ash Research, Development and Data Center. One-hundred and seventy-eight representative ashes were divided into three groups according to their analytical CaO content: low-calcium, <10%; intermediate-calcium, 10–20%; high-calcium, 20+%. Statistical analyses were performed within each of the three groups. Thirty-two plots relating chemical composition, mineralogy and physical test results are presented. Extensive discussions relating the chemistry and mineralogy of the ash to the source coal, the distribution of the chemical constituents among crystalline and glassy phases, and the reactions of these phases in concrete are given. The consistency of high-calcium fly ash generated at a Midwestern U.S. power station fired with Wyoming bituminous coal was studied using ninety-three ashes collected over a two year period. The availability of mineralogy for each ash leads to a more thorough understanding of the bulk chemical and physical test results used in evaluating fly ashes for utilization, and in modeling their behavior after disposal

Rietveld quantitative X-ray diffraction analysis of NIST fly ash standard reference materials

2000 ◽  
Vol 15 (3) ◽  
pp. 163-172 ◽  
Author(s):  
Ryan S. Winburn ◽  
Dean G. Grier ◽  
Gregory J. McCarthy ◽  
Renee B. Peterson
Keyword(s):  
Fly Ash ◽  
Diffraction Analysis ◽  
Reference Materials ◽  
Internal Standard ◽  
Standard Reference Materials ◽  
Ratio Method ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray ◽  
High Calcium

Rietveld quantitative X-ray diffraction analysis of the fly ash Standard Reference Materials (SRMs) issued by the National Institute of Standards and Technologies was performed. A rutile (TiO2) internal standard was used to enable quantitation of the glass content, which ranged from 65% to 78% by weight. TheGSASRietveld code was employed. Precision was obtained by performing six replicates of an analysis, and accuracy was estimated using mixtures of fly ash crystalline phases and an amorphous phase. The three low-calcium (ASTM Class F) fly ashes (SRM 1633b, 2689 and 2690) contained four crystalline phases: quartz, mullite, hematite, and magnetite. SRM 1633b also contained a detectable level of gypsum, which is not common for this type of fly ash. The high-calcium (ASTM Class C) fly ash, SRM 2691, had eleven crystalline phases and presented a challenge for the version ofGSASemployed, which permits refinement of only nine crystalline phases. A method of analyzing different groups of nine phases and averaging the results was developed, and tested satisfactorily with an eleven-phase simulated fly ash. The results were compared to reference intensity ratio method semiquantitative analyses reported for most of these SRMs a decade ago.

scholarly journals Quantification of plasma remdesivir and its metabolite GS-441524 using liquid chromatography coupled to tandem mass spectrometry. Application to a Covid-19 treated patient

2020 ◽  
Vol 58 (9) ◽  
pp. 1461-1468 ◽  
Author(s):  
Jean-Claude Alvarez ◽  
Pierre Moine ◽  
Isabelle Etting ◽  
Djillali Annane ◽  
Islam Amine Larabi
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Half Life ◽  
Limit Of Detection ◽  
Treated Patient ◽  
Internal Standard ◽  
Therapeutic Drug ◽  
Active Metabolites ◽  
Limit Of Quantification ◽  
Positive Mode

AbstractObjectivesA method based on liquid chromatography coupled to triple quadrupole mass spectrometry detection using 50 µL of plasma was developed and fully validated for quantification of remdesivir and its active metabolites GS-441524.MethodsA simple protein precipitation was carried out using 75 µL of methanol containing the internal standard (IS) remdesivir-13C6 and 5 µL ZnSO4 1 M. After separation on Kinetex® 2.6 µm Polar C18 100A LC column (100 × 2.1 mm i.d.), both compounds were detected by a mass spectrometer with electrospray ionization in positive mode. The ion transitions used were m/z 603.3 → m/z 200.0 and m/z 229.0 for remdesivir, m/z 292.2 → m/z 173.1 and m/z 147.1 for GS-441524 and m/z 609.3 → m/z 206.0 for remdesivir-13C6.ResultsCalibration curves were linear in the 1–5000 μg/L range for remdesivir and 5–2500 for GS-441524, with limit of detection set at 0.5 and 2 μg/L and limit of quantification at 1 and 5 μg/L, respectively. Precisions evaluated at 2.5, 400 and 4000 μg/L for remdesivir and 12.5, 125, 2000 μg/L for GS-441524 were lower than 14.7% and accuracy was in the [89.6–110.2%] range. A slight matrix effect was observed, compensated by IS. Higher stability of remdesivir and metabolite was observed on NaF-plasma. After 200 mg IV single administration, remdesivir concentration decrease rapidly with a half-life less than 1 h while GS-441524 appeared rapidly and decreased slowly until H24 with a half-life around 12 h.ConclusionsThis method would be useful for therapeutic drug monitoring of these compounds in Covid-19 pandemic.

Determination of Free Solanesol Levels in Cigarette Filters by Liquid Chromatography–Mass Spectrometry

2021 ◽  
Author(s):  
Roberto Bravo Cardenas ◽  
Phuong Ngac ◽  
Clifford Watson ◽  
Liza Valentin-Blasini
Keyword(s):  
Liquid Chromatography ◽  
Sample Preparation ◽  
Tobacco Smoke ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Filter Material ◽  
Previous Method ◽  
Tobacco Smoke Exposure ◽  
Triple Quadrupole Mass Spectrometer ◽  
Cigarette Butts

Abstract Solanesol, a naturally occurring constituent of tobacco, has been utilized as a good marker for environmental tobacco smoke particulate and as a noninvasive predictor of mainstream cigarette smoke tar and nicotine intake under naturalistic smoking conditions. A fast and accurate method for measuring free solanesol to assess tobacco smoke exposure is highly desirable. We have developed and validated a new environmentally friendly, high-throughput method for measuring solanesol content in discarded cigarette filter butts. The solanesol deposited in the used filters can be correlated with mainstream smoke deliveries of nicotine and total particle matter to estimate constituent delivery to smokers. A portion of filter material is removed from cigarette butts after machine smoking, spiked with internal standard solution, extracted and quantitatively analyzed using reverse-phase liquid chromatography coupled to a triple-quadrupole mass spectrometer. The new method incorporates a 48-well plate format for automated sample preparation that reduces sample preparation time and solvent use and increases sample throughput 10-fold compared to our previous method. Accuracy and precision were evaluated by spiking known amounts of solanesol on both clean and smoked cigarette butts. Recoveries exceeded 93% at both low and high spiking levels. Linear solanesol calibration curves ranged from 1.9 to 367 µg/butt with a 0.05 µg/butt limit of detection.

Influence of Radiopacity of Dental Composites on the Diagnosis of Secondary Caries: The Correlation Between Objective and Subjective Analyses

2014 ◽  
Vol 39 (1) ◽  
pp. 90-97 ◽  
Author(s):  
AD Cruz ◽  
RG Esteves ◽  
IAVP Poiate ◽  
PP Portero ◽  
SM Almeida
Keyword(s):  
Rating Scale ◽  
Pearson Correlation ◽  
Internal Standard ◽  
Dental Composites ◽  
Internal Diameter ◽  
X Rays ◽  
Human Teeth ◽  
Secondary Caries ◽  
Pixel Intensity ◽  
Dental Tissues

SUMMARY This study aimed to objectively evaluate the radiopacity of different dental composites and their subjective influence on diagnosing secondary caries–like lesions and how these results correlate. For objective analysis, three resin specimens (1 mm thick, with a 4-mm internal diameter) were made with four composites: 1) Charisma; 2) Filtek Z250; 3) Prisma AP.H; and 4) Glacier. Three human teeth were selected and then mesio-distally sectioned (1 mm thick) to make the dental specimens. An aluminum (Al) wedge (12 steps, 1 mm thick, 99.8% purity) was used as an internal standard to calculate the radiopacity. For subjective analysis, 20 human teeth were selected and then prepared with a mesio-occluso-distal (MOD) inlay cavity, with half the teeth receiving a round cavity to simulate the carious lesion. The MOD was restored using the composites at four different times. Standardized radiographs were acquired and then digitized (300 dpi and eight-bit TIFF) for both analyses. A histogram objectively measured the pixel intensity values of the images, which were converted into millimeters of Al using linear regressions. Eight observers subjectively evaluated the images using a five-point rating scale to diagnose the caries. The data were statistically analyzed using the Student t-test, the Kappa test, diagnostic testing, and the Pearson correlation coefficient (α=0.05). All materials showed radiopacity values compatible with dental tissues (p&gt;0.05); Glacier was similar to dentin and Prisma AP.H was similar to enamel, while the remaining materials showed a middle radiopacity. Prisma AP.H and Glacier differed (p&lt;0.05) in relation to their accuracy to caries diagnosis, with Glacier having greater accuracy. There was a correlation between objective and subjective analyses with negative linear dependence. An increase in the material's radiopacity could have a subjectively negative influence on the diagnosis of secondary caries; thus, an ideal radiopacity for a dental composite is closer to the dentin image and produces similar attenuation to X-rays than does dentin.

Influence of Different Mineral Precursors on the Properties of Fly Ash Based Alkali-Activated Mortars

2018 ◽  
Vol 761 ◽  
pp. 73-78 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Chemical Composition ◽  
Coal Combustion ◽  
Pure Aluminum ◽  
Partial Replacement ◽  
Black Coal ◽  
Fly Ashes ◽  
Final Composition ◽  
Alkali Activated

Alkali-activated materials based on fly ash are widely developed and also produced on the present. Some of fly ashes are not suitable for production of alkali-activated materials because of their inconvenient chemical composition. Alumina-silicates are the most important components that are needed to accomplish the successful reaction. The proper content of amorphous phase of alumina-silicates and its proportion as well should be provided for the final composition of alkali-activated materials. The influence of pure aluminum oxide powder as well as raw milled natural perlite on mechanical properties and durability of alkali-activated mortars was investigated. These minerals were used as partial replacement of fly ash coming from black coal combustion. In addition, the mortars were prepared by using different alkali activators.

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