Extended thermodynamic retention model

The first effort to use LSERs in IPC relied on a retention equation based on a mixture of stoichiometric and electrostatic models. Several approximations were made [1-3]. First, ion-pairing in the eluent was neglected, but this is at variance with clear qualitative and quantitative experimental results [4-13]. In Chapter 3 (Section 3.1.1), the detrimental consequences of this assumption were clarified and danonstiated that extensive experimental evidence cannot be rationalized if pairing interactions in the eluent are not taken into account. Furthermore, in the modeling of A as a function of the analyte nature, the presence of the IPR in the eluent was assumed not to influence the retention of neutral analytes. This assumption is only occasionally true [14,15] and the extended thermodynamic retention model of IPC suggests the quantitative relationship between neutral analytes retention and IPC concentration in the eluent [16]. 

Starting from this idea, Cecchi and co-workers snbmitted an extended thermodynamic theoretical treatment of the retention behavior that covers and comprehends both stoichiometric and gennine electrostatic models bnt surpasses them [20,26,27,50-64]. The subject is not difficnlt and a tutorial description is given below. More detailed and comprehensive descriptions of the model can be found elsewhere [20,63],... 

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