Fluorescence analysis of iodinated acetophenone derivatives

2015 ◽  
Vol 139 ◽  
pp. 63-67 ◽  
Author(s):  
F. Crivelaro ◽  
M.R.S. Oliveira ◽  
S.M. Lima ◽  
L.H.C. Andrade ◽  
G.A. Casagrande ◽  
...  
Keyword(s):  
Fluorescence Analysis ◽  
Acetophenone Derivatives

An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement

1992 ◽  
Vol 50 (2) ◽  
pp. 1758-1759
Author(s):  
D. A. Carpenter ◽  
M. A. Taylor
Keyword(s):  
Imaging Techniques ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Specimen Preparation ◽  
X Rays ◽  
Glass Capillary ◽  
Close Coupling ◽  
X Ray ◽  
Point To Point ◽  
Beam Damage

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Sorption of Se (IV) from aqueous solutions with subsequent determination by X-ray fluorescence analysis

2020 ◽  
Vol 86 (10) ◽  
pp. 5-9
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
V. V. Es’kina ◽  
V. B. Baranovskaya ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluorescence Analysis ◽  
Standard Samples ◽  
Phase Contact Time ◽  
Sorbent Phase ◽  
X Ray ◽  
Fundamental Parameters ◽  
Inductively Coupled ◽  
Subsequent Determination

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

Quantitative Measurement of Fluorescent Layers with Respect to Spatial Thickness Variations and Substrate Properties

2020 ◽  
Vol 74 (4) ◽  
pp. 439-451
Author(s):  
Philipp Holz ◽  
Christoph Pönisch ◽  
Albrecht Brandenburg
Keyword(s):  
Manufacturing Industry ◽  
Quantitative Measurement ◽  
Fluorescence Emission ◽  
Fluorescence Analysis ◽  
Thin Layers ◽  
Fluorescence Signal ◽  
Functional Coatings ◽  
Custom Made ◽  
Substrate Properties ◽  
Thickness Variations

Imaging fluorescence spectroscopy proves to be a fast and sensitive method for measuring the thickness of thin coatings in the manufacturing industry. This encouraged us to systematically study, theoretically and experimentally, parameters that influence the fluorescence of thin layers. We analyzed the fluorescence signal as a function of the scattering and reflectance properties of the sample substrate. In addition, we investigated effects of the layer properties on fluorescence emission. A ray-tracing software is used to describe the influence of these parameters on the fluorescence emission of thin layers. Experiments using a custom-made system for imaging fluorescence analysis verify the simulations. This work shows a factor five variation of fluorescence intensity as a function of the reflectance of the sample substrate. Simulations show variations by a factor of up to eight for samples with different surface roughness. Results on tilted samples indicate a significant increase of the detected fluorescence signal, for fluorescent droplets on reflective substrates, if illuminated and coaxially observed at angles greater than 25°. These findings are of utmost relevance for all applications which utilize the fluorescence emission to quantify thin layers. These applications range from in-line lubricant monitoring in press plants to monitoring of functional coatings in medical technology and the detection of filmic contaminations.

l-Prolinal Dithioacetal: A Highly Effective Organocatalyst for the Direct Nitro-Michael Addition to Selected Cyclic and Aromatic Ketones

Synthesis ◽  
2019 ◽  
Vol 51 (17) ◽  
pp. 3356-3368
Author(s):  
Piotr Pomarański ◽  
Zbigniew Czarnocki
Keyword(s):  
Michael Addition ◽  
Ring Size ◽  
Cyclic Ketones ◽  
Asymmetric Syntheses ◽  
Aromatic Ketones ◽  
Ring Systems ◽  
Effective Catalyst ◽  
Acetophenone Derivatives ◽  
Highly Effective ◽  
Related Compounds

The synthesis of novel l-prolinal dithioacetal and its application as an organocatalyst for the direct Michael addition of cyclic ketones and acetophenone derivatives to trans-β-nitrostyrene and related compounds is described. The prolinal dithioacetal acts as effective catalyst in the case of cyclic ketones of different ring size, in particular five- and six-membered examples, as well as larger and smaller ring systems. High enantioselectivity and diastereoselectivity is observed for different substrates and trans-β-nitrostyrenes. Also, the first asymmetric syntheses of selected 2-methyl-4-nitro-1,3-diphenylbutan-1-one derivatives by application of the obtained organocatalyst is presented.

Energy-Dispersive X-ray Fluorescence Analysis as a Rapid Method for Identifying Tephras

1983 ◽  
Vol 19 (2) ◽  
pp. 201-211 ◽  
Author(s):  
A. B. Cormie ◽  
D. E. Nelson
Keyword(s):  
Reliable Method ◽  
Fluorescence Analysis ◽  
Energy Dispersive ◽  
Bulk Glass ◽  
X Ray ◽  
Additional Tool ◽  
White River ◽  
Routine Identification ◽  
Weathering Effects ◽  
Mount St Helens

AbstractThe use of energy-dispersive X-ray fluorescence analysis (XES) for the routine identification of three tephras (Mazama, Bridge River, Mount St. Helens Yn) commonly found in archeological sites in British Columbia has been investigated. Researchers have often assumed that chemical analysis of bulk samples of glass separates would be hampered by contamination and weathering effects. Our results indicate that XES of bulk glass separates provides a very reliable method for rapidly identifying the three tephras in question, even with a very simple sample preparation. This should enable persons not skilled in geology or in tephrochronology to collect and to identify samples of these tephras. Finally, as a part of the study, similar measurements were made on the separated glass portions of these three tephras and of three others (Glacier Peak B and G, White River) from northwest North America. The results suggest that this method may provide tephrochronologists with a useful additional tool for studying tephras in other regions.

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