Laminar Flow and Radial Mixing in FIA

The radial dispersion can be promoted by introducing turbulent flow or secondary flow, by diffusion alone, or by a combination of these effects. 

Secondary flow, combined with molecular diffusion promotes the radial transport in a powerful way. Its intensity increases with geometrical disorientation of the flow path. Thus, coiling of the tubes induces a gentle 

Molecular diffusion was identifled as the important factor influencing overall design of the flow channel already in the first theoretical paper on FIA [20]. Since then its role in FIA processes has been clarified and mathematically described in a number of detailed papers. Works of Van-derslice et al. [1061], Wada [1065] and Hungerford [3.4] focused attention on molecular diffusion as the sole tool for redistribution of sample elements in radial direction. Their results, observations, and conclusions are reviewed in the next section. 

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