Radiocarbon evaluation of natural/synthetic ratio in citric acid samples

A method is described for the evaluation of the natural/synthetic ratio in citric acid samples. The method is based on measurements of the activity of carbon-14 present in citric acid of natural origin. The parameters that affect the radiocarbon counting (background emission, scintillation quenching and relative efficiency) are discussed. Two different procedures are described which can also be applied to the evaluation of the natural/synthetic origin of other carbon-containing compounds.