ABSTRACT
Key factors in IPC separations are the kind and concentration of the ion-pairing reagent (IPR). The popularity of different classes of IPRs changes quickly and this in turn led to dynamic development of new IPC features. As a result, this versatile technique proved capable of tracking novel analytical needs. Figure 7.1 details the distribution of traditional and innovative IPRs in 2008. This chapter explains their attributes and uses. Clearly the major role for positively charged IPRs is still played by classical organic ammonium ions, whereas for negatively charged IPRs, perfluorinated carboxylic acids and chaotropic lipophilic salts are outperforming traditional sulfonium organic ions. The breakthrough of ionic liquids is also noteworthy and the simultaneous use of both positive and negative IPRs gained some interest. The essential role played by IPRs in IPC is described in Chapter 3.
