Isotopmerking

Isotopmerking, also known as isotopic labeling, is a technique used in chemistry and biology where atoms of a specific element within a molecule are replaced by a different isotope of the same element. Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons. This difference in neutron number leads to a different atomic mass.

The most common isotopes used for labeling are stable isotopes, such as deuterium (²H) for hydrogen, carbon-13 (¹³C) for carbon, and nitrogen-15 (¹⁵N) for nitrogen. Radioactive isotopes can also be used, like carbon-14 (¹⁴C) or tritium (³H), although these require special handling due to their radioactivity.

The purpose of isotopmerking is to track the fate or transformation of a molecule within a system. By introducing a molecule with labeled atoms, researchers can follow its path using techniques like mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, or scintillation counting. This allows for the study of metabolic pathways, reaction mechanisms, and the distribution of substances in biological organisms. For example, in drug development, isotopmerking can help understand how a drug is absorbed, metabolized, and excreted by the body. In chemical synthesis, it can elucidate the step-by-step process of a reaction. The key principle is that the labeled atoms behave chemically identically to their natural counterparts, ensuring the labeled molecule follows the same pathways.