Search results
Results from the WOW.Com Content Network
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.
Due to the non-linearity of the equation, numerical techniques such as the non-linear least-squares method can be used to solve the van Genuchten parameters. [4] [5] The accuracy of the estimated parameters will depend on the quality of the acquired dataset (and ). Structural overestimation or underestimation can occur when water retention ...
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 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.
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.
Chemical equation Stoichiometry. Law of definite proportions ... Van Deemter equation; Phase separations ... Van der Waals force; Thermodynamics
The Kovats index applies to organic compounds.The method interpolates peaks between bracketing n-alkanes.The Kovats index of n-alkanes is 100 times their carbon number, e.g. the Kovats index of n-butane is 400.