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September 2022


Journal/Book: Reprinted from Nature Vol. 205 No. 4977 pp. 1190-1191 March 20 1965. 1965;

Abstract: By DR. URSULA LÜTHI and PROF. P. G. WASER Institute of Pharmacology University of Zurich A UTORADIOGRAPHIC methods have not yet found application to thin-layer chromatography of 3Hlabelled compounds because of the low tritium energy (Emax = 18·5 keV; Emean = 5·7 keV). The tritium range in a layor of sodium-o-(carboxymethyl) cellulose and in sodium alginate has been determined by Isbell Frush and Peterson1 to be 0·28 mg/cm2. The surface density of a 250-µ thin layer of silica-gel G or cellulose is 5·5 mg/cm² or 7·5 mg/cm2 respectively. This is about 20 times the tritium range which means a self-absorption loss of radiation of more than 95 per cent. If the thin-layer material is mixed with an adequate scintillator the tritium radiation can be made visible by the fluorescence induced in the scintillator provided the scintillator molecules are within the range of the tritium -particles and the thin layer is transparent for the fluorescence radiation. We therefore prefer the term 'fluorography' to the misleading name 'autoradiography'. The maximum range of a tritium -particle expressed in microns in a silica-gel layer of 250µ can be calculated from its surface density and its thickness: 250 x 0·28/5·5 = 12·7µ. Two methods of using scintillators for fluorograms ... schö

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