Ion pair extraction titration
HOW TO DETERMINE THE ACTIVE INGREDIENT USING THE ION PAIR EXTRACTION METHOD
This ion pairing technique has been widely used in pharmaceutical control for many years.
The techniques were initially developed within the framework of liquid-liquid extraction methods to improve the extraction yield of certain ionic species. Subsequently, the notion of ion pair was quickly adapted to spectroscopic (especially colorimetry) and volumetric assays of a certain number of acids and bases of pharmaceutical interest.
The principle of ion-pair assay methods:
Ion pairs are Coulombic associations between two ions of opposite electrical charge. Electrical charges imply that the dielectric constant ε0, of a solvent, the distance between ions and the temperature will have an influence on the ion pairing.