Liquid Scintillation Counting of C14O2 in Aqueous Carbonate Solutions
Two methods of assaying C14O2 by liquid scintillation spectrometry have been published [1,2,4] and widely used. The homogeneous systems [1,4] obtained by absorbing dry gaseous C14O2 in a quaternary ammonium base, such as hydroxide of hyamine, are rapid and convenient where only small quantities of these expensive reagents are required. However, these systems become inconvenient when large samples of moist air containing low specific activity C14O2 must be assayed, as in animal metabolism studies. In these cases, the heterogeneous system of Nathan et al. , in which the C14O2 is precipitated as BaCO3 and counted as a suspension in liquid scintillator gel, has been the method of choice despite the fact that the BaCO3 precipitation, drying, grinding, and weighing procedures in this method require several laboratory man hours of preparation time for each sample.
KeywordsLiquid Scintillation Counting Efficiency Absolute Sensitivity Expensive Reagent Counting Vial
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