Method of isotopic perturbation

{
  "id": "MLC-T-CHM-007277",
  "term": "Method of isotopic perturbation",
  "field": "Chemistry",
  "definition": "An NMR method for deciding whether a species is one symmetric structure or a rapidly equilibrating pair of equivalent asymmetric ones. Isotopic substitution, such as deuterium at one site, makes the two forms of the equilibrium unequal, so the time-averaged chemical shifts split. A split signal indicates an equilibrating mixture, whereas an unsplit signal indicates a single symmetric structure.",
  "subject": "Organic and Biomolecular Chemistry",
  "see_also": [
    "isotope effect"
  ],
  "references": [
    "PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1132 (https://doi.org/10.1351/pac199466051077)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/method-of-isotopic-perturbation/"
}