Acid–base partition cleanup is a liquid–liquid extraction procedure for the
separation of acid analytes, such as organic acids and phenols from base/
neutral analytes (amines, aromatic hydrocarbons, halogenated organic
compounds) using pH adjustment. This method is used for the cleanup of
petroleum waste prior to analysis or further cleanup. The extract from
the prior solvent extraction is shaken with water that is strongly basic. The
basic and neutral components stay in the organic solvent, whereas the acid
analytes partition into the aqueous phase. The organic phase is concentrated
and is ready for further cleanup or analysis. The aqueous phase is acidified
and extracted with an organic solvent, which is then concentrated (if
needed) and is ready for analysis of the acid analytes (Figure 1.8).