Macro elemental analysis of food samples by nuclear analytical technique

Carcinogenic N-nitroso compounds are found ubiquitously in the human environment and their isolation and identification in food samples constitutes an important step tcwards successful cancer prophylaxis. This study is concerned with the origin of volatile N-nitrosamines in some food samples. An attempt has been made to elucidate the mechanism of N-nitrosopyrrolidine formation in cooked bacon. The precursors and conditions that influence N-nitrosopyrrolidine f o r m t ion in bacon are discussed with special errphasis on manipulations that can reduce or eliminate the N-nitr osami ne content of bacon, such as cooking by microwave radiation. Based on model system studies a pathway for Nnitrosopyrrolidine formation is proposed. The presence of volatile Nnitrosamines in Ouzo and other anise-based distilled spirits (Raki, Pernod) which are consumed widely in Greece and around the Mediterranean was also investigated. Analytical aspects concerning the extraction and estimation of Nnitroso compounds in food samples were also considered. An analytical technique for the extraction of volatile N-nitrosamines from alcoholic beverages was devised, based cn liquid-liquid extraction cn a column packed with anhydrous Na2S04 , Celite and acid washed Celite. Finally, a method for the sequential determination of both volatile and non-volatile N-nitroso compounds in cured neats was developed. This is based cn a digestion-centrifugation technique by which volatile and nonvolatile N-nitroso compounds are extracted in the aqueous phase. Subsequently, the volatiles are extracted first into dichloromethane followed by the extraction of non-volatiles into ethyl acetate.

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Sample Preparation Using Graphene-Oxide-Derived Nanomaterials for the Extraction of Metals

Molecules ◽

10.3390/molecules25102411 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2411 ◽

Cited By ~ 4

Author(s):

Natalia Manousi ◽

Erwin Rosenberg ◽

Eleni A. Deliyanni ◽

George A. Zachariadis

Keyword(s):

Graphene Oxide ◽

Metal Ions ◽

Environmental Remediation ◽

Deep Eutectic Solvents ◽

Food Samples ◽

Single Atom ◽

Functionalized Graphene Oxide ◽

Heterogenous Catalysis ◽

Analytical Technique ◽

Atom Layer

Graphene oxide is a compound with a form similar to graphene, composed of carbon atoms in a sp2 single-atom layer of a hybrid connection. Due to its significant surface area and its good mechanical and thermal stability, graphene oxide has a plethora of applications in various scientific fields including heterogenous catalysis, gas storage, environmental remediation, etc. In analytical chemistry, graphene oxide has been successfully employed for the extraction and preconcentration of organic compounds, metal ions, and proteins. Since graphene oxide sheets are negatively charged in aqueous solutions, the material and its derivatives are ideal sorbents to bind with metal ions. To date, various graphene oxide nanocomposites have been successfully synthesized and evaluated for the extraction and preconcentration of metal ions from biological, environmental, agricultural, and food samples. In this review article, we aim to discuss the application of graphene oxide and functionalized graphene oxide nanocomposites for the extraction of metal ions prior to their determination via an instrumental analytical technique. Applications of ionic liquids and deep eutectic solvents for the modification of graphene oxide and its functionalized derivatives are also discussed.

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X-Ray Fluorescence Critical Sample Thickness and Volume of Material Excited in Catalysts

Advances in X-ray Analysis ◽

10.1154/s0376030800018747 ◽

1992 ◽

Vol 36 ◽

pp. 145-154

Author(s):

Frank Kunz ◽

Ronald Belitz

Keyword(s):

Elemental Analysis ◽

Precious Metals ◽

Sample Thickness ◽

Depth Of Penetration ◽

X Ray ◽

Analytical Technique ◽

Elemental Concentrations ◽

The Past ◽

Quantitative Elemental Analysis ◽

Beam Depth

During the past fifteen years wavelength dispersive x-ray fluorescence (WDXRF) spectrometry has been the primary analytical technique for quantitative elemental analysis of automotive catalyst precious metals, contaminants, and substrate materials. While extensive work has been devoted to improving the accuracy of WDXRF quantitative procedures, minimal attention has been given to the calculation of critical sample thickness (primary x-ray beam depth of penetration) and total volume of material excited for each element in the catalyst. However, with the increasing use of WDXRF for measuring and comparing elemental concentrations at the inlet, middle, and outlet surfaces of catalysts, critical sample thickness and volume of material excited becomes very important for accurate interpretation of results.

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Trends in Electron Energy Loss Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078675 ◽

1977 ◽

Vol 35 ◽

pp. 228-229

Author(s):

C. Colliex ◽

P. Trebbia

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Electron Energy Loss Spectroscopy ◽

Materials Science ◽

Analytical Technique ◽

Recent Developments ◽

Quantitative Results ◽

Electron Microscopes ◽

Electron Energy Loss ◽

Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

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