Solid activation analysis

Although following similar nuclear reaction schemes, nuclear analytical methods (NAMs) comprise bulk analysing capability (neutron and photon activation analysis, NAA and PAA, respectively), as well as detection power in near-surface regions of solids (ion-beam analysis, IB A). NAMs aiming at the determination of elements are based on the interaction of nuclear particles with atomic nuclei. They are nuclide specific in most cases. As the electronic shell of the atom does not participate in the principal physical process, the chemical bonding status of the element is of no relevance. The general scheme of a nuclear interaction is ... 

Charged particle activation analysis (CPAA) is based on charged particle induced nuclear reactions producing radionuclides that are identified and quantified by their characteristic decay radiation. CPAA allows trace element determination in the bulk of a solid sample as well characterization of a thin surface layer. 

The Szilard-Chambers Reactions in Solids Garman Harbottle and Norman Sutin Activation Analysis D. N. F. Atkins and A. A. Smales... 

Chemically pure reagents were used. Cadmium was added as its sulfate salt in concentrations of about 50 ppm. Lanthanides were added as nitrates. For the experiments with other metal ions so-called "black acid from a Nissan-H process was used. In this acid a large number of metal ions were present. To achieve calcium sulfate precipitation two solutions, one consisting of calcium phosphate in phosphoric acid and the other of a phosphoric acid/sulfuric acid mixture, were fed simultaneously in the 1 liter MSMPR crystallizer. The power input by the turbine stirrer was 1 kW/m. The solid content was about 10%. Each experiment was conducted for at least 8 residence times to obtain a steady state. During the experiments lic iid and solid samples were taken for analysis by ICP (Inductively Coupled Plasma spectrometry, based on atomic emission) and/or INAA (Instrumental Neutron Activation Analysis). The solid samples were washed with saturated gypsum solution (3x) and with acetone (3x), and subsequently dried at 30 C. The details of the continuous crystallization experiments are given in ref. [5]. 

Cadmium in acidified aqueous solution may be analyzed at trace levels by various instrumental techniques such as flame and furnace atomic absorption, and ICP emission spectrophotometry. Cadmium in solid matrices is extracted into aqueous phase by digestion with nitric acid prior to analysis. A much lower detection level may be obtained by ICP-mass spectrometry. Other instrumental techniques to analyze this metal include neutron activation analysis and anodic stripping voltammetry. Cadmium also may be measured in aqueous matrices by colorimetry. Cadmium ions react with dithizone to form a pink-red color that can be extracted with chloroform. The absorbance of the solution is measured by a spectrophotometer and the concentration is determined from a standard calibration curve (APHA, AWWA and WEF. 1999. Standard Methods for the Examination of Water and Wastewater, 20th ed. Washington, DC American Public Health Association). The metal in the solid phase may be determined nondestructively by x-ray fluorescence or diffraction techniques. 

Chemical compound homogeneity is an important issue for pharmaceutical sohd forms. A classical spectrometer integrates the spatial information. In solid form analysis, use of a mean spectrum on a surface can be a drawback. For example, in the pharmaceutical industry it is important to map the distribution of active ingredients and excipients in a tablet so as to reveal physical interaction between the compounds and help to solve homogeneity issues. Spectroscopic imaging techniques that visualize chemical component distribution are thus of great interest to the pharmaceutical community. 

W.H. Barber, O.H. Dengel, R.H. Vogt C.V. Strain, Activation Analysis of Sodium and Potassium in Solid Propellants , NuclTechnol... 

Species distribution studies have shown that trace element (e.g. metals) concentrations in soils and sediments vary with physical location (e.g. depth below bed surface) and with particle size. In these speciation studies the total element content of each fraction was determined using a suitable trace element procedure, for example, solid sample analysis by X-ray emission spectroscopy or neutron activation analysis, or alternatively by dissolution of sample and analysis by ICPOES, AAS or ASV. The type of sample fraction analysed can vary, and a few... 

Recently, the development of extremely high resolution solid state Ge(Li) gamma-ray detectors, the application of gamma-gamma coincidence techniques, and the availability of low cost 14 MeV neutron generators have renewed interest in activation analysis as a means for routine rapid and non-destructive elemental abundance determinations of both major and trace elements. Some of these new techniques will be discussed in the sections that follow. 

The recent general availability of solid state Ge(Li) gamma-ray detectors has made possible new applications of activation analysis to multielement trace analysis. A simplified schematic representation of a Ge(Li) detector is given in Fig. 6. The principal advantage of these detectors is their excellent energy resolution for gamma-ray spectrometry 52>. While a typical 3 X 3" NaI(Tl) scintillation crystal may have a photopeak resolution of 50 KeV fwhm (/ull width at Aalf maximum) for the 137Cs... 

Voighl, A. F., D. E. Becknell, and Sr. L. Menapace Comparison of Solid State and Scintillation Gamma-Ray Spectrometry in Analysis. The 1968 International Conference Modern Trends in Activation Analysis, Gaithersburg, Maryland, October 7—11, 1968, Paper 106. 

Neutron activation analysis 30-45 Fast to slow depending on element Solids or liquids... 

Each spectroscopic method has a characteristic application. For example, flame photometry is still applicable to the direct determination of Ca and Sr, and to the determination of Li, Rb, Cs and Ba after preconcentration with ion-exchange resin. Fluorimetry provides better sensitivities for Al, Be, Ga and U, although it suffers from severe interference effects. Emission spectrometry, X-ray fluorescence spectrometry and neutron activation analysis allow multielement analysis of solid samples with pretty good sensitivity and precision, and have commonly been applied to the analysis of marine organisms and sediments. Recently, inductively-coupled plasma (ICP)... 

The same methods can be used for determining the chemical composition of the liquid phase as those used for the composition of the solid after digestion or extraction (absorption and emission spectroscopy, electroanalytical methods, ion-selective electrodes, neutron activation analysis, mass spectrometry, etc.). The humic substances of natural waters can also be analyzed. 

In activation analysis, as in all trace element determinations, care must be exercised to avoid contamination. One of the advantages of activation analysis is that the manipulation prior to irradiation of the sample is minimized. Contamination by inactive material after irradiation is unimportant, provided it does not take place in amounts sufficient to affect the chemical yield. The restrictions imposed on neutron activation by selfshielding mentioned above may necessitate the use of small samples and either liquid or solid dilutions of the pure standard material to overcome the difficulty. 

Activation analysis has been applied to some of the problems connected with the study of luminescent solids and phosphors. Grillot (50) determined 10 gm of copper in solids at different stages in the preparation of luminescent substances and Bancie-Grillot and Grillot (5) determined chlorine in zinc sulfide. The thallium content of potassium iodide crystals has been measured by Delbecq et al. SO), and an accuracy of 5% at the microgram level claimed. 

Schomburg A, Kirchner H, Atzpodien J Renal, metabolic, and hemodynamic side-effects of interleukin-2 and/or interferon alpha evidence of a risk/benefit advantage of subcutaneous therapy, J Cancer Res Clin Oncol 1993,119 745-755 Margolin KA, Rayner AA, Hawkins MJ, Atkins MB, Dutcher JP, Fisher Rl, Weiss GR, Doroshow JH, Jaffe HS, Roper M, et al. Inter-leukin-2 and lymphokine-activated killer cell therapy of solid tumors analysis of toxicity and management guidelines, J Clin Oncol 1989,7 486-498... 

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