The chemical analysis of hydrated uranium tetrafluoride is described. This product was obtained in a wet process. Several
methods were taken into account and applied to this product. In the case of uranium the following techniques were employed:
isotope dilution with mass spectrometry, X-ray fluorescence, volumetric measurements, spectrophotometry, Volkovs's method,
natural radioactivity measurements using the 185 keV235U peak and neuton activation analysis. In the case of fluoride determination, four methods gave good results. An explanation
is given for a discrepancy appearing in one case. Free water in the product was determined in the classical way at 105 °C,
with the Karl Fischer reagent and by thermogravimetric analysis. Hydration water was also estimated from thermogravimetric
determinations in nitrogen to avoid product oxidation. Thus the formula UF42·2H2O was found. Other impurities were determined by emission spectroscopy, mass spectrometry, neutron activation and chemical
Authors:H. Finston, E. Williams, S. Bauman, S. Jacobson, and A. Bond
The low energy particle accelerator at Brooklyn College is being applied to chemical analysis by studies of: charged particle
induced nuclear reactions, proton induced X-ray emission, and inelastic neutron scattering. Fluorine-containing gaseous compounds
in the atmosphere and fluorine in airborne particulates will be determined by detection of the prompt gamma-rays and/or alpha
particles emitted in the reaction19F(p,a)16O. The PIXE technique is being applied to analysis of a variety of environmental samples, and activation by inelastic neutron
scattering is being investigated for elements which are not amenable to thermal neutron activation.
Authors:E. Mackey, D. Anderson, H. Chen-Mayer, R. Downing, R. Greenberg, G. Lamaze, R. Lindstrom, D. Mildner, and R. Paul
At the National Institute of Standards and Technology, there are two techniques for chemical analysis that use neutron beams from the reactor for target irradiation: neutron depth profiling (NDP) and prompt -ray activation analysis (PGAA). There are two facilities for each technique, one equipped with a thermal neutron beam and the other, with a cold neutron beam. In addition, focused beams of cold neutrons will be used to measure the two-dimensional element distributions by PGAA and three-dimensional distributions by NDP. This paper includes a brief description of the facilities, the measurement capabilities of each, some recent applications of NDP and PGAA, and neutron focusing as applied to these techniques.
Authors:R. Hancock, W. Fox, T. Conway, and L. Pavlish
Since it is now possible, with some reliability, to separate native from European copper using chemical analysis, we now sort archaeological copper into geological (North American) or smelted (European) groups and thereby help address issues relating to the cultural impact of earliest aboriginal — European contact in northeastern Ontario. Twenty six metal samples from 11 archaeological sites, dating from the 17th to 19th centuries, were analyzed by INAA. The results were compared with reference data for native copper and European trade copper and indicate that of the 17 copper samples in the suite, an archaeologically-unexpected high number of 12 were made of native copper. The majority of these samples (7 of 8) derived from the post-contact early 17th century Providence Bay Odawa village. The remaining samples were made of brass (8) and zinc (1). Two of the brass samples, from Point Louise, have remarkably similar chemistries and probably came from the same object, or at least from the same batch of brass.
A procedure for the complete chemical analysis of magnesium or sodium diuranate (yellow cake) sample is reported. Uranium is determined gravimetrically after peroxide precipitation. Optimum parameters, such as pH, quantity of hydrogen peroxide, volume of sample, temperature and complexing agent for quantitave precipitation of uranium, and effective separation of other elements were studied. Aluminum, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn were determined by flame atomic absorption spectrometer and B, Mo, SO4, REEs and Y by inductively coupled plasma atomic emission spectrometer in the filtrates of hydroxide and peroxide precipitation separation. The proposed method is accurate and the precision is characterized by an RSD of ~0.2% for U; 2 to 6% for Mg, Na, K, Ca, Fe, SiO2, Al, Cd, Co, Cr, Fe, Mn, Ni, Pb, and Zn and 3 to7% for REEs, Y, Mo and B
Authors:J. Mufari, P. Miranda-Villa, A. Bergesse, N. Cervilla, and E. Calandri
, M. , Vega-Galvez , A. , Uribe , E. , López , J. , Martínez , E. , Rodríguez , M. , Quispe , I. & DI Scala , K. ( 2011 ): Physico-chemicalanalysis, antioxidant capacity and vitamins of six ecotypes of Chilean quinoa (Chenopodium
Authors:K. Graikou, K. S. Baranek, A. Pietrosiuk, H. Damianakos, M. Jeziorek, and I. Chinou
Four alkannins, isobutylalkannin (1), β,β-dimethylacrylalkannin (2), acetylalkannin (3) and β-hydroxyisovalerylalkannin (4), two shikonofurans: shikonofuran C (5), shikonofuran D (6), and a number of sterols as well as esterified acids, have been isolated and determined from the n-hexane extract of Lithospermum canescens transgenic roots. Pigments 1 and 4 are reported in the present work as novel metabolites within Lithospermum genus, while it is also the first detailed chemical analysis of transgenic roots from the studied species. All chemical structures were determined by modern chromatographic and spectral means as GC-MS, ESI-MS, and NMR.
An account is given of the principle of optical microanalysis of the surface of a metallic or insulating solid through atomic
ionoluminescence. Essentially, this method involves bombarding the surface to be studied with high-velocity positive ions,
and recording the local emission of light resulting from the de-excitation of the pulverized atoms on the surface of the target.
Two original and complementary instruments are described: an optical microanalyser and an ionprobe microanalyser; examples
of possible applications are given, followed by a discussion of the performances and potentials of these systems, which are
open to still further refinements.
The effect of short-term higher ambient temperature (HT) and continuous vibration (CV) treatment was comparatively characterized by sensory evaluation and chemical analysis. Results of quantitative descriptive analysis of modified frequency (MF) showed that HT causes both in red wine and white wine a decrease of fruity and floral characters, an unbalance of taste, and a shortness of aftertaste length. CV wine showed very close sensory characters to control in most terms evaluated. Seventy-four volatile compounds were quantitative analysed by solid phase microextractiongas chromatography-mass spectrometry, and the principal component analysis (PCA) was conducted on the 23 volatiles of highest odour activity value (OAV). The concentrations of potential fruity and floral aroma attributors like isoamyl acetate, ethyl butanoate, ethyl 2-methylbutanoate, ethyl hexanoate, ethyl octanoate, β-damascenone, and linalool were lower in HT wine than that in original wine and CV wine.