Determination of Tritium and C¹⁴ in Biological Samples by Rapid Combustion Techniques

Abstract

An important factor contributing to the increased use of tritium, and C¹⁴ as well, has been the availability of reliable and convenientto-operate commercial equipment that measures radioactivity by the liquid scintillation technique. This technique offers advantages of simplicity, sensitivity, and routine use that cannot be matched by alternative methods. However, inherent in liquid scintillation technique are two difficulties which make direct application to biological samples impractical. First, organic solvents are necessary for liquid scintillation counting. These are often immiscible with aqueous biological systems and are poor solvents for the polar constituents of biological samples. Second, liquid scintillation technique requires a relatively colorless sample so that the light resulting from the interaction of the beta particle with the phosphor in solution may reach the phototube. Any absorption of light manifests itself as a quenching, thus resulting in lowered counting efficiency.

Presented at the Fifth Symposium on Advances in Tracer Methodology, 1961.