Retention Times and Band Profiles in Linear Chromatography

1 Retention Times and Band Profiles in Linear Chromatography 

Two important solutions have been derived for gradient elution in linear chromatography one pertaining merely to analytical applications, the other addressing the wider problem of the periodic injection of pulses of any width in a gradient of any profile. 

The behavior of chromatographic columns operated in gradient elution, under linear conditions i.e., assuming linear isotherms for all the solutes) has been studied theoretically by numerous authors [2,4-10]. The most comprehensive treatment is that based on the linear solvent strength (LSS) theory of Snyder et al. [5,6]. This theory has formd widespread acceptance [7,8] and has been extended to include the contributions of the various mass transfer resistances to band broadening [9-11]. It assumes the injection of infinitesimal pulses of a feed and a linear gradient of the volume fraction of a mobile phase modifier, cf). 

Assuming that Eq. 15.3 is locally valid in gradient elution, the elution time of a component at any position, z, along the column is given by 

Gradient Elution Chromatography under Nonlinear Conditior  

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