Automatic sample combustion methods for the determination of soft beta-emitting isotopes in dual labelled organic compounds and biological materials by liquid scintillation counting

Abstract

Automatic sample preparation methods for the determination of carbon–14 and/or tritium, and carbon–14 and/or sulfur–35 in dual labelled samples by liquid scintillation counting are presented. The sample is burnt in a stream of oxygen, and the combustion products carrying radioisotopes are subsequently separated and collected for radioactivity determination. Tritium is measured as water, carbon–14 as “carbamate” and sulfur–35 as sulfuric acid. The procedures run automatically, they are free of memory effect and cross contamination, and provide quantitative recovery.