CONTRIBUTIONS TO THE THEORY OF LINEAR MULTIPHASE CHROMATOGRAPHY

An isothermal one-dimensional reactor of infinite length is considered where an arbitrary number of co-current phases flow at different rates, containing also a solute (or tracer). Interfacial reactions between the single tracer components as well as axial diffusion with generally different diffusivities in the phases are supposed to take place ("multiphase chromatography"). Defining the overall flux (at a given place in the tube) as the response of the system, the impulse response is, as a rule, equal to the density of the residence time distribution of the tracer particles. A straightforward algorithm to determine the asymptotic semi-invariants of the impulse response for large values of the axial coordinates is given. In the case of "chromatography" (in the literal sense), the first three semi-invariants (mean, variance, and skewness) are given explicitly. The concept of "generalized chromatography" has been introduced, and the respective moments have been calculated.