Plate height retention

Distribution constant Selectivity factor Resolution Number of plates Plate height Retention time... 

Elution volume, exclusion chromatography Flow rate, column Gas/liquid volume ratio Inner column volume Interstitial (outer) volume Kovats retention indices Matrix volume Net retention volume Obstruction factor Packing uniformity factor Particle diameter Partition coefficient Partition ratio Peak asymmetry factor Peak resolution Plate height Plate number Porosity, column Pressure, column inlet Presure, column outlet Pressure drop... 

Recovery factor Reduced column length Reduced plate height Reduced velocity Relative retention ratio Retardation factor d Retention time Retention volume Selectivity coefficient Separation factor... 

The column performance (efficiency) is measured either in terms of the plate height (H), the efficiency of the column per unit length, or the plate number (N), i.e. the nnmber of plates for the column. This number depends upon the column length (L), whereas the plate height does not. The mathematical relationships between the nnmber of plates, the retention time of the analyte and the width of the response is shown in the following equations ... 

H is the plate height (cm) u is linear velocity (cm/s) dp is particle diameter, and >ni is the diffusion coefficient of analyte (cm /s). By combining the relationships between retention time, U, and retention factor, k tt = to(l + k), the definition of dead time, to, to = L u where L is the length of the column, and H = LIN where N is chromatographic efficiency with Equations 9.2 and 9.3, a relationship (Equation 9.4) for retention time, tt, in terms of diffusion coefficient, efficiency, particle size, and reduced variables (h and v) and retention factor results. Equation 9.4 illustrates that mobile phases with large diffusion coefficients are preferred if short retention times are desired. 

Pio. 15. Graph illustrating the dependence of the reduced plate height on the carbon load of octadecyl silica uuionary phase, prepared Aom Fsitisil with octadecyltrichloro-silane. Ehieiit. methanol-water eiuite, polyey aromatic hydrocarbons retention foctor, 4. Prom the dM of Henman er of. (7 5). 

In pHPLC, there are numerous types of columns used. The comparison and characterization of these columns are often discussed in terms of thermodynamic properties and kinetic characteristics. The retention factor, k, selectivity, a, and the peak asymmetry are believed to be representative parameters for the thermodynamic properties, while the kinetic characteristics are often expressed in dimensionless magnitudes of reduced plate height, h, separation impedance, E, and flow resistance factor, ( ). 3... 

Separation Parameters Retention Ratio, Plate Height, Resolution,... 

Substances A and B were found to have retention times of 17-30 and 19-92 minutes respectively on a 25-0 cm column. The widths (at the base) for A and B were 1-10 and 1-22 minutes respectively. The average number of plates in the column and the plate height calculated resolutions. 

A solute with a retention time of 407 s has a width at the base of 13 s on a column 12.2 m long. Find the number of plates and plate height. 

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