Radioanalysis

Three healthy male beagles receive an intravenous dose into a jugular vein or into the vena cephalica antebrachii (typically 1-5 mg/kg b.w.). After a wash out period dependent on the duration of excretion of the drug/metabolites (typically 4 weeks at minimum), the same animals are dosed orally by using a stomach tube (typical dose 10 mg/kg b.w.). Normally, 5-10 MBq/animal is a sufficient radioactive dose for a 14C-label, in case of 3H about 50 MBq/animal could be used. Up to 168 h after administration, blood, urine and feces are collected. At each collection time about 3.5 mL of blood are taken for radioanalysis (2-3 aliquots) and for processing plasma for subsequent radio- and bioanalysis in plasma (also 2-3 aliquots each). The plasma is aliquoted immediately after centrifugation without warm-up. At a few preselected time points additional blood is collected for metabolite investigations (about 5 mL). 

Radioanalysis is performed by the liquid scintillation procedure either directly after addition of a scintillator (urine, cage washing) or following combustion and addition of a scintillator (blood, plasma, feces). 

The urine is collected according to the preinstructed collection intervals directly from the urine collection container of the metabolism cage. The samples are weight and directly after stirring and homogenizing the urine, aliquots are taken for radioanalysis. The remainder is bottled and frozen for additional investigations planned (metabolite profile and identification and/or bioanalysis). 

The pooled bile is intensively homogenized, the homogenicity and the exact concentration proven by radioanalysis of serveral aliquots. The amount... 

Addition of radioactive tracers for analytical purposes offers additional possibilities of radioanalysis. By isotopic dilution not only elements, but also compounds, can be determined quantitatively, provided that these compounds are available in labelled form. Radiometric methods comprise application of isotopic exchange, release of radionuclides and radiometric titration. 

Radioactivity (activity) Property of matter exhibiting (radioactive) decay or isomeric transition of atomic nuclei and emission of nuclear radiation [Bq = s ] Radioanalysis Analysis by means of radioactive atoms (radionuclides) Radiocolloids Colloids (i.e. matter in the colloidal state) consisting of the radioactive matter considered (intrinsic colloids) or containing microamounts of radioactive matter (carrier colloids)... 

Applications include the use of radionuclides in geo- and cosmochemistry, dating by nuclear methods, radioanalysis, the use of radiotracers in chemical research, Mossbauer spectrometry and related methods, the use of radionuclides in the life sciences, in particular in medicine, technical and industrial applications and investigations of the behaviour of natural and man-made radionuclides, in particular actinides and fission products, in the environment (geosphere and biosphere). Dosimetry and radiation protection are considered in the last chapter of the book. 

The concentration of natural lithium (tritium-precursor) in un-irradiated Magnox RPV steel has been estimated directly using SIMS-MS and SEM-EDX and indirectly from measuring tritium induced by neutron activation of mainly Li. Tritium was measured in surveillance specimens irradiated during the 26 year operational life of a Magnox reactor followed by radioactive decay of approximately 15 years. For comparison purposes, inactive archive RPV steel was also irradiated in the CONSORT reactor followed immediately by radioanalysis for tritium. In this way, the possibility of diffusive transfer of tritium into or out of the steel during residence in the reactor could be evaluated. 

The Environment Agency and Food Standards Agency funded this work as part of their respective radiological surveillance programmes. The authors would also like to express their sincere thanks to our colleagues at Cefas and Harwell Scientifics for their contributions to the collection, distribution, preparation and radioanalysis of samples. 

Besides a number of special techniques, in principle, the following analytical methods are applicable for the qualitative and quantitative determination of isotopes emission and absorption spectrometry, NMR and ESR spectrometry, mass spectrometry and radioanalysis. 

Two studies discuss the acute absorption of radiolabeled maneb in rodents. The first study (Brocker and Schlatter 1979) used unfasted adult female rats dosed with [ " Mnjmaneb at a dose of 4-10 mg/kg. The rats were kept in metabolism cages which allowed the collection of respired air, urine, and feces for several hours post-dosing. The maneb was given alone or in conjunction with different metal compounds. Radioanalysis of excreta and selected tissues revealed that at 72 hours post-dosing, only 4-6% of the radioactivity was retained in the body with the majority of the label located within the liver and kidney. For 2 different chemical preparations of maneb, the recovery of label in feces was 94-96%, with the remainder in the urine. The respired air of two rats contained only 0.24 and 0.60% of the label, respectively. When molar excesses of the chloride salts of zinc, copper, iron, and mercury were added with the maneb. 

Atmospheric Pollution 1982 edited by M.M. Benarie Air Pollution by Nitrogen Oxides edited by T. Schneider and L. Grant Environmental Radioanalysis by H.A. Das, A. Faanhof and H.A. van der Sloot Chemistry for Protection of the Environment edited by L. Pawlowski, A.J. Verdier and W.J. Lacy... 

Das, H.. Faanhof, A., van der Sloot, H., 1983. Environmental Radioanalysis. Elsevier, Amsterdam, pp. 296. Davies, B., 1994. Chemistry and bioavailability with special reference to trace elements In Farago, M. (Ed.), Plants and the Chemical Elements. VCH Publishers, Weinheim, pp. 1-30. 

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