Turbulent-flow chromatography particle size

Turbulent flow chromatography is a direct-inject sample-preparation technique that is accomplished on a special chromatography column. The technique has some applicability toward plasma and serum. The special column combines large particle (50 lm) and frit size (20 lm) with high flow rate (5 to 10 mL/ min) to achieve eddies and nonlaminar flow. Under this arrangement, improved... 

A new on-line approach to SPE is the use of so-called turbulent flow chromatography which combines rapid mobile phase linear velocities with larger particle sizes this approach was discussed in Section 3.5.9 in the context of breakdown of the conventional (van Deemter) rate theory. Whether or not the flow can truly be described as turbulent (Ayrton 1998), there is no question that eddies are formed that enhance the interactions of smaller molecules with the stationary phase. In contrast the large proteins and other biopolymers have rates of mass transfer from the liquid to stationary phase (C term in the van Deemter equation) that are too... 

The term A is related to the flow profile of the mobile phase as it traverses the stationary phase. The size of the stationary phase particles, their dimensional distribution, and the uniformity of the packing are responsible for a preferential path and add mainly to the improper exchange of solute between the two phases. This phenomenon is the result of Eddy diffusion or turbulent diffusion, considered to be non-important in liquid chromatography or absent by definition in capillary columns, and WCOT (wall coated open tubular) in gas phase chromatography (Golay s equation without term A, cf. 2.5). 

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