While many studies report CMC values for a specific LLE system, it is important to note that it is a resource-intensive endeavor that requires the examination of extractant or other key variables across a range of concentrations. Interfacial tension is a common method of determining the CMC, where the CMC can be readily identified as a kink delineating two linear regimes within in concentration dependent studies. Sometimes multiple linear regimes can be identified, with multiple CMC's indicating changes in the structural form or shapes of the aggregates. Other direct methods of measuring the CMC, include sharp transitions in vapour pressure osmometry, spectrophotometry, fluorometry, and conductivity. Advanced techniques such as small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) also provide direct evidence of micellization, but are time-consuming and required data post-processing instead of direct reading. Although some analytical and numerical predictions of the CMC exist, and there are correlations with enhancement of the extraction of solutes like metal ions, in general the changes to the speciation before and after the CMC are not well-understood.