The measurement of isotope effects typically involves comparing the reaction rates of a substrate with the lighter isotope (e.g., hydrogen) to the same substrate with the heavier isotope (e.g., deuterium). This comparison yields a ratio known as the kinetic isotope effect (KIE).
The KIE is calculated using the formula: \[ \text{KIE} = \frac{k_{\text{H}}}{k_{\text{D}}} \] where \(k_{\text{H}}\) and \(k_{\text{D}}\) are the rate constants for the reactions involving hydrogen and deuterium, respectively.
