Methods for radiochemical and radionuclidic purity determination of some99mTc and113mIn radiopharmaceuticals

In order to determine the radiochemical impurities in pertechnetate solution as well as that of unbound^99mTc in its colloid and complex compounds, in indium chloride solution and related compounds, paper chromatography on Whatman No. 1, thin-layer chromatography on silica gel plates, and paper electrophoresis were applied. A simple method for the determination of radionuclidic purity was developed.     

Analytical procedures for radiochemical control of water-soluble99mTc-labelled radiopharmaceuticals

In this paper chromatographic systems for the accurate and reliable determination of the percentage of different species (free pertechnetate, particulate^99mTc and labelled^99mTc) in^99mTc-labelled radiopharmaceuticals are described. The procedures are based on the simultaneous run of two different chromatograms, one in 85% CH₃OH and the other in 15% H₃PO₄. Also, 0.9% NaCl can be used instead of 15% H₃PO₄ for the second chromatogram. Alternative procedures applying two dimensional chromatography on Whatman No. 1 paper or silica G plates with 85% CH₃OH for the first run and 15% H₃PO₄ for the second are given. The applicability of these procedures is limited to water-soluble radiopharmaceuticals.     

13C N.M.R. and 14N N.Q.R. in ferroelectric liquid crystals Polar versus quadrupolar ordering

Abstract

¹³C nuclear magnetic resonance and ¹⁴N nuclear quadrupole resonance spectra of ferroelectric smectic C?liquid crystals and their non-chiral analogues allow for a microscopic determination of the polar and quadrupolar (or bipolar) biasing of rotation around the long molecular axis as well as for a determination of the anisotropy in the fluctuations of this axis. The results show that the microscopic origin of the biquadratic coupling between the polarization and the tilt, which has been recently introduced into the extended Landau model of the S_A–S?_C transition, is the quadrupolar (or bipolar) rotational bias induced by the anisotropy in the fluctuations of the long molecular axis. The tilt induced anisotropy in the fluctuations is practically identical in chiral and non-chiral smectic C phases.     

13C N.M.R. and 14N N.Q.R. in ferroelectric liquid crystals Polar versus quadrupolar ordering

¹³C nuclear magnetic resonance and ¹⁴N nuclear quadrupole resonance spectra of ferroelectric smectic C*liquid crystals and their non-chiral analogues allow for a microscopic determination of the polar and quadrupolar (or bipolar) biasing of rotation around the long molecular axis as well as for a determination of the anisotropy in the fluctuations of this axis. The results show that the microscopic origin of the biquadratic coupling between the polarization and the tilt, which has been recently introduced into the extended Landau model of the S_A-S*_C transition, is the quadrupolar (or bipolar) rotational bias induced by the anisotropy in the fluctuations of the long molecular axis. The tilt induced anisotropy in the fluctuations is practically identical in chiral and non-chiral smectic C phases.     

Some radiochemical separations employed at the Institute of Nuclear and Energy Research-Brazilian Nuclear Energy Commission

Several radiochemical separations have been employed at the Radiochemistry Division of the Institute of Nuclear and Energy Research-Brazilian Nuclear Energy Commision, for the analysis of a number of elements in different kinds of matrices. In the present paper some of these separations applied to the analysis of geological samples, geological and biological reference materials and Brazilian foodstuffs are described. The separation procedures utilized are mainly ion exchange, retention in inorganic exchangers like HAP, TDO and HMD and solvent extraction.     

Some considerations on semiemperical estimation of 13C-proton N.M.R. coupling constants

The well known relation between the ¹J_CH coupling constant and the (%S) is reviewed in order to introduce the influence of the charge distribution on the CH bond. The direct influence turns out to be small for ordinary molecules, but it might be such more important for charged species.     

Some N.M.R. experiments using lyotropic nematic liquid crystals

A series of lyotropic nematic liquid crystals based on aniso-dimensional micelles can be subdivided according to micelle shape and diamagnetic susceptibility anisotropy. The proton magnetic resonance spectra of benzene dissolved in dilute solution in several of these phases have been analysed. The signs of the partially averaged dipole-dipole coupling give information about the relative alignment of the six-fold symmetry axis of benzene, the director and the magnetic field. The system caesium perfluorooctanoate/water is unusual in two respects. The system forms a nematic phase with only a binary mixture and the disk micelles align in a perpendicular plane to the magnetic field. As a result the binary system has been studied previously in some detail (see N. Boden, S. A. Come and K. W. Jolley, 1987, J. phys. Chem.91, 4092). New measurements on the interesting phase diagram have been accomplished using caesium-133 and deuterium magnetic resonance measurements at various temperatures. Some dilatometric measurements have been made to complement the N.M.R. studies.     

Some N.M.R. experiments using lyotropic nematic liquid crystals

Abstract

A series of lyotropic nematic liquid crystals based on aniso-dimensional micelles can be subdivided according to micelle shape and diamagnetic susceptibility anisotropy. The proton magnetic resonance spectra of benzene dissolved in dilute solution in several of these phases have been analysed. The signs of the partially averaged dipole–dipole coupling give information about the relative alignment of the six-fold symmetry axis of benzene, the director and the magnetic field. The system caesium perfluorooctanoate/water is unusual in two respects. The system forms a nematic phase with only a binary mixture and the disk micelles align in a perpendicular plane to the magnetic field. As a result the binary system has been studied previously in some detail (see N. Boden, S. A. Come and K. W. Jolley, 1987, J. phys. Chem. 91, 4092). New measurements on the interesting phase diagram have been accomplished using caesium-133 and deuterium magnetic resonance measurements at various temperatures. Some dilatometric measurements have been made to complement the N.M.R. studies.     

Cyclotron isotopes and radiopharmaceuticals XXXI. Improvements in77Br production and radiochemical separation from enriched78Se+

An improved method for production of >100 mCi of⁷⁷Br with the⁷⁸Se(p, 2n)⁷⁷Br nuclear reaction and a 4π water-cooled target containing encapsulated metallic⁷⁸Se or a Pb⁷⁸Se alloy has been developed. The⁷⁷Br was separated with ∼98% radiochemical yield and a radionuclidic purity of 98.9%. The time required to isolate carrier-free⁷⁷Br free of metallic impurities was less than 4hrs. Isotopically enriched⁷⁸Se was quantitatively recovered. This research was partially supported by NIH Grant No. Ro1 H1 18487-01, and Performed at Brookhaven National Laboratory under contract with the U.S. Department of Energy and supported by its Division of Basic Energy Sciences.     

Le Groupe de Recherche du C.R.N.S. Application des Reactions Nucleaires a l'Analyse Chimique G.A.R.N.A.C.

In this article the research topics dealt with at Research Group for Applications of Nuclear Reactions to Chemical Analysis (GARNAC) are described. Particular emphasis is laid on the main contribution of the GARNAC to the development and the evolution of charged particle activation analysis, evolving with the analytical studies performed and with the scientific and technical progress realized in material and semiconductors science.      

Some observations on the inner layer at the mercury—Electrolyte interface

A simple model is developed to account for the inner layer entropy of formation of the Hg—electrolyte interface. It is shown that this two-state model, based on the orientational behaviour of the water molecules within the inner layer, cannot be used to describe simultaneously both the inner layer entropy and the differential capacity. The relationship of this model to those developed by previous investigators for the differential capacity is discussed.     

Radioanalytical quality control of11C,18F and123I-labelled compounds and radiopharmaceuticals

Radiochemical quality control using high performance high pressure liquid chromatography and, to some extent, gas chromatography is described for a variety of carrier-free¹¹C-,¹⁸F-and¹²³I-labelled compounds and radiopharmaceuticals. The particular problems associated with the handling of carrier-free compounds labelled with short-lived radionuclides are outlined, and chromatographic data are given for the separation and purification of such products.     

The use of liquid scintillation spectrometry for the determination of radionuclidic purity of 90Y from a radiochemical 90Y/90Srgenerator

Summary An extraction technique for the separation of ⁹⁰Sr from a high excess of⁹⁰Y has been developed. This procedure can be used for the determination of trace amounts of⁹⁰Sr in⁹⁰Y prepared by a radiochemical⁹⁰Y/⁹⁰Sr generator by liquid scintillation.     

Radio TLC in quality control and development of radiopharmaceuticals

Radio TLC has been used for determining the radiochemical purity and composition of two^99mTc-radiopharmaceuticals, available as kits and commonly used for diagnostic imaging. Moreover, the same technique has been applied to detect impurities which decrease the specific activity of¹³¹I-derivatized dermatan sulfate, a new potential radiopharmaceutical, and for establishing the best labeling conditions.