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Theoretical Models of Ion Pair Chromatography: A Close Up of Recent Literature Production

The use of ionic additives to dramatically extend the range of solute polarity amenable to RP-HPLC began to be exploited in the 1970s. Ion pair chromatography has readily become an intriguing separation strategy: it makes use of ionic Ion Pair Reagents to increase retention of oppositely charged analytes, under RP-HPLC conditions. It is also well recognized that these additives have a significant influence on the peak shape of ionogenic analytes and on the figures of merit of their chromatographic separations. As evidenced by the studies described in this review, retention modeling may offer much potential to help chromatographers perform educated guesses and shorten the optimization process of separations. Although the last years have seen many application of IPC in routine analyses, there is a minimal amount of published work concerning retention modeling in IPC. The purpose of the current review is to bridge the past with the future, with regard to the theoretical facets of this technique, and to provide a critical and comparative survey of the latest theoretical advances in IPC.