Liquid chromatography in which the mobile liquid phase contains an ionized additive (an ion-pair reagent) that can form an ion pair with an analyte molecule.
Note: Separations occur due to the difference in the ability to form ion pairs and/or in the distribution coefficients of the ion pairs between the mobile and stationary phases.
Source:
PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 187 (https://doi.org/10.1515/pac-2017-0111)