Radioactivity ether-extractable

Figure 8. Plasma levels of A -THC, ether-extractable radioactivity, and total radioactivity after iv injection of -tx -THC (5.G-7.9 ng/kg) in three human...

Of the total radioactivity in fish, ether extracted 78.26, petroleum ether 10.79, and methanol 10.95%. Percent composition of each of these fractions is shown in vertical column. 

Figure S. TLC of the fish and soil extractable radioactivity and water from the 14C-DDT experiment. Solvent system used was petroleum etheridiethyl ether...

Samples of the day 0 and day 10 homogenates were extracted and partitioned as shown schematically in Fig. 10.2. The petroleum ether and Sep-Pak acetonitrile fractions were analysed by HPLC (Fig. 10.3). The HPLC analyses showed a similar metabolite profile, with a lower percentage of PBO in the day 10 sample (24.4 of TRR) than in the day 0 sample (49-3% of TRR). The HPLC profile of the petroleum ether extracts showed that the predominant radioactivity extracted into the petroleum ether was parent compound (6.3 ppm for day 10). Numerous metabolites were observed in (he HPLC profile of the Sep-Pak... 

Radioiododeboronation. A solution of 11-cholesterylundec-l-en-l-yl boronic acid (20 pi of a 0.5 M solution in 50 aqueous THF), THF (85 pi), and Na I (5 pi) was mixed in a vial. Chloramine-T (25 pi of a 0.5 M solution in 50% aqueous THF) was added and the reaction mixture capped and allowed to stand at room temperature for 1 h. The product was extracted into ether (4x1 ml) and concentrated with a stream of nitrogen. The concentrate was spotted equally on two TLC plates and developed with 4% ether/petroleum ether. The radioactive bands corresponding to the product were scraped and extracted with ether (4x1 ml). The radiochemical yield was 17%. 

The uranium was further purified by preolpltatlon as dluranate, sodium uranyl acetate, and peroxide and by a final ether extraction. Throughout this final series of purifications there was no detectable decrease In P-actlvlty this Indicates that the uranium was radioactive pure. 

Cesium isotopes can be recovered from fission products by digestion in nitric acid, and after filtration of waste the radioactive cesium phosphotungstate is precipitated using phosphotungstic acid. This technique can be used to prepare radioactive cesium metal or compounds. Various processes for removal of Cs isotopes from radioactive waste have been developed including solvent extraction using macrocycHc polyethers (62) or crown ethers (63) and coprecipitation with sodium tetraphenylboron (64). 

In a way related are the complexes formed by Hg salts and multicrown dendrimers of different generations (dendrimers with a polypropylene amine interior of different volume and benzo[15]-crown-5 ether periphery), studied by extraction methods using radioactive 203Hg2+.210 Up to 12 Hg2+ ions were found to be bound per dendrimer molecule, obviously in the amine-dominated interior, not in the crown-ether periphery. 

Butex A process for separating the radioactive components of spent nuclear fuel by solvent extraction from nitric acid solution, using diethylene glycol dibutyl ether (also called Butex, or dibutyl carbitol) as the solvent. Developed by the Ministry of Supply (later the UK Atomic Energy Authority) in the late 1940s. Operated at Windscale from 1952 until 1964 when it was superseded by the Purex process. 

The most widely used technique for the separation of large quantities of radioactive material is that of solvent extraction. The principle of the method is that ideally the partition coefficient of a compound between two solvents does not depend on concentration in a given set of conditions. This was shown in an early paper of Graham and Sea-borg (35) who demonstrated that the partition coefficients of gallium and cobalt chlorides between ether and aqueous hydrochloric acid were the same for concentrations of lCTli molar (i. e. no added carrier) as for 1-6xl0 s molar. 

Crown ethers and cryptands, either alone or fixed on a polymer support [2.89], have been used in many processes, including selective extraction of metal ions, solubilization, isotope separation [2.90], decorporation of radioactive or toxic metals [2.17, 2.49], and cation-selective analytical methods [2.89, 2.91, 2.92] (see also Sect. 8.2.2 and 8.4.5). A number of patents have been granted for such applications. 

Method. 1 mmole of compound is added to 1 ml of anhydrous pyridine in a S-ml flask. 2 mmoles of [I4C]acetic anhydride are then added for each expected reactive group (e.g., hydroxyl). The resulting mixture is heated at 12S °C for 4 h, cooled and poured into SO ml of cold water. This solution is transferred to a separating funnel and extracted with SO ml of diethyl ether. The diethyl ether is then washed three times with dilute hydrochloric acid, and once with each of dilute sodium hydroxide, water and saturated sodium chloride. The diethyl ether is dried with anhydrous sodium sulfate and evaporated to dryness for radioactive counting (using a proportional-flow counter or a scintillation counter). 

Dozol, J.F., Bohmer, V., McKervey, A. et al. 1997. New macrocyclic extractants for radioactive waste treatment Ionizable crown ethers and functionalized calixarenes. Report EUR-17615. 

Delmau, L.H., Bonnesen, P.V., Moyer, B.A. 2004. A solution to stripping problems caused by organophilic anion impurities in crown-ether based solvent extraction systems A case study of cesium removal from radioactive wastes. Hydrometallurgy 72 (1-2) 9-19. 

J.-F. Dozol, V. Bohmer, M. A. McKervey, F. Lopez-Calahorra, D. N. Reinhoudt, M. J. Schwing, R. Ungaro and G. Wipff, New macrocyclic extractants for radioactive waste treatment Ionizable crown ethers and functionalized calixarenes, EUR-OP Reference CG-NA-17615-EN-C (EUR-17615), European Commission, Nuclear Science and Technology, Luxembourg, 1997. 

Delmau, L. H., Bonnesen, P. V., and Moyer, B. A. A Solution to Stripping Problems Caused by Organophilic Anion Impurities in Crown-Ether Based Solvent Extraction Systems, A Case Study of Cesium Removal from Radioactive Wastes, Hydrometallurgy 72(1,2) (2004), 9-19. 

The most significant information in the present study arises from a radically different approach to these metabolite investigations. Four years ago, we reported that an appreciable proportion of the total radioactivity in Rhesus monkey urine could be extracted with ether, even without prior hydrolysis (13). This excretion was highly pH-dependent -- with the curve s inflection point being near pH 4 (Figure 12) — indicating that the materials being extracted were probably carboxylic acids. 

Crown ethers are also used to remove radioactive elements from radioactive waste. For example, radioactive cesium and strontium can be extracted using specialized derivatives of 18-crown-6. 

The tren-based heteroditopic receptor 22, featuring a tripodal tetrahedral amide hydrogen-bond anion-recognition site in combination with benzo-15-crown-5 ether cation-binding moieties, has been found to cooperatively bind chloride, iodide, and perrhenate anions via co-bound crown ether-complexed sodium cations. It also can efficiently extract the radioactive sodium pertechnetate from simulated aqueous nuclear waste streams. The anion-binding affinity of 22 is considerably reduced in the absence of a co-bound cation <1999CC1253>... 

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