Eric Schram

Determination of tritium and carbon-14 in aqueous solution with anthracene powder

Abstract A method is described for the counting or recording of carbon-14 and tritum activities in aqueous solutions by means of an anthracene powder cell. Efficiencies of 44 and 2%, respectively, are obtained for an effective volume of 1 ml and with a background of about 60 counts/min at ordinary temperature.

Determination continue du carbone-14 et du soufre-35 en milieu aqueux par un dispositif a scintillation. Application aux effluents chromatographiques

A recording apparatus is described for determining soft radiation (C/sup 14/, S/sup 35/) in aqueous medium, especially adapted for continuous analysis of chromatographic effluents. It is based upon the spreading of the liquid in a thin layer in contact with a plastic scintillator coupled to a coincidence circuit. The efficiency is comparable to that of a thin endwindow GM counter in the absence of auto-absorption. (auth)

Application of Scintillation Counters to the Assay of Bioluminescence

Publisher Summary The use of bioluminescence as an analytical tool has opened a new field of application for scintillation counters although all the capabilities of these instruments are not fully exploited. The method offers numerous advantages: high sensitivity and specificity, absence of fractionation procedures, digital response and possibility of flow-measurements. The liquid scintillation counters have proved useful as quantum counters for the bioluminescence assays to the measurement of adenosine triphosphate (ATP) by means of firefly extracts, reduced flavine–mononucleotide (FMN), nicotinamide–adenine–dinucleotide (NAD), and nicotinamide–adenine–dinucleotide–phosphate (NADP). The time-course of bioluminescent reactions is characterized by a very sharp initial increase followed by a slower decrease of the light emission. The method of firefly luciferase is applied to the study of photophosphorylation processes in acetabularia mediterranea, under different conditions of illumination, study of the activation of amino acids, and the assay of ATP and adenosine diphosphate in blood. Since Warburg, the spectrophotometric or fluorimetric determination of NAD has become one of the most widespread methods for the assay of an impressive number of biological substrates and enzymes as well as for the study of enzyme kinetics.