2. Addition of radioisotopes or stable isotopes

Methods based on the addition of radioisotopes or stable isotopes have a multitude of applications. They are a very convenient and often very safe way of marking an element in order to follow its movements, locate it or measure it. Only the latter is dealt with in this article. Table 4 shows the main radioisotopes used for marking. These and many other radioisotopes can easily be obtained by irradiating the natural element with reactor neutrons (exception ³ H, ¹⁴ C, ²¹⁰ Pb). Table 5 shows the main stable isotopes used to assay light elements. These isotopes are marketed in the form of 90-99% enriched labeled molecules. It is also possible...