A semi-automatic combustion method for the simultaneous determination of3H and35S in doubly labelled organic materials by liquid scintillation counting

A sample preparation method developed for the simultaneous liquid scintillation assay of tritium and³⁵S in doubly labelled organic materials is described. The sample is burnt in a stream of oxygen and the radioactive isotope carriers formed are collected separately for individual counting.³⁵S content of the sample is measured as a dilute sulfuric acid solution, while the tritium is counted as water. The procedure is free of cross-contamination and memory effect, provides quantitative analytical recovery, and the final solutions ready for counting are obtained in twelve minutes.