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The van Deemter equation is a hyperbolic function that predicts that there is an optimum velocity at which there will be the minimum variance per unit column length and, thence, a maximum efficiency. The van Deemter equation was the result of the first application of rate theory to the chromatography elution process.
Jan Jozef van Deemter (31 March 1918 – 10 October 2004) was a Dutch physicist and engineer known for the Van Deemter equation in chromatography. [1] [2] [3]He obtained his doctorate in physics from the University of Amsterdam in June of 1950.
A faster flow rate of the eluent minimizes the time required to run a column and thereby minimizes diffusion, resulting in a better separation. However, the maximum flow rate is limited because a finite time is required for the analyte to equilibrate between the stationary phase and mobile phase, see Van Deemter's equation.
The main application of size-exclusion chromatography is the fractionation of proteins and other water-soluble polymers, while gel permeation chromatography is used to analyze the molecular weight distribution of organic-soluble polymers.
The same equation applies in chromatography processes as for the packed bed processes, namely: = In packed column chromatography, the HETP may also be calculated with the Van Deemter equation. In capillary column chromatography HETP is given by the Golay equation.
The parameters are largely derived from two sets of chromatographic theory: plate theory (as part of partition chromatography), and the rate theory of chromatography / Van Deemter equation. Of course, they can be put in practice through analysis of HPLC chromatograms, although rate theory is considered the more accurate theory.
Van Deemter equation; W. Weak affinity chromatography This page was last edited on 6 August 2019, at 13:49 (UTC). Text is available under the Creative Commons ...
Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. [1]It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. [2]