Shows how a difference between the distribution coefficient of two components can lead
to separation in capillary gas chromatography. Students select column length, column
internal diameter, thickness of stationary phase, diffusion coefficient in mobile phase,
viscosity of carrier gas, flow rate, ambient temperature, and column temperature.
The simulation calculates the phase ratio, capacity factor, selectivity, linear velocity
of carrier, retention time of unretained peak, retention time of the two components, plate height,
efficiency (plate count), peak base width, and resolution. Displays plot of simulated
chromatogram showing two component peaks and an unretained peak.

Inputs:
column length, cm L
column internal diameter, cm id
thickness of stationary phase, cm df
diffusion coefficient in mobile phase, cm2/min Dm
viscosity of carrier gas, poise eta
volumetric flow rate, mL/min Fo
distribution coefficient of component a Kda
distribution coefficient of component b Kdb
ambient temperature, K Ta
column temperature, K Tc
ambient pressure, psi Pa
vapor pressure of water, psi Pwater
Outputs:
phase ratio ß =i d/(4*df)
capacity factor of component a ka = Kda/beta
capacity factor of component b kb = Kdb/beta
selectivity a = kb/ka
adjusted flow rate, mL/min Fc = Fo*(Tc/Ta)*(Pa-Pwater)/Pa
linear velocity of carrier, cm/min v = Fc/(3.14159*(id/2-df)^2)
retention time of unretained peak, min to = L/v
retention time of component a, min tra = (ka*to)+to
retention time of component b, min trb =( kb*to)+to
plate height, cm h = (2*Dm)/v+((id/2)^2*((1+6*kb+11*kb*kb)/(24*(1+kb)*(1+kb)))/Dm)*v
efficiency (plate count) N = L/h
peak base width a, min twa = tra/sqrt(N/16)
peak base width b, min twb = trb/sqrt(N/16)
resolution R = sqrt(N)*((alpha-1)/alpha)*(kb/(1+kb))/4

(c) 1991, 2000, Prof. Tom O'Haver , Professor Emeritus,
The University of Maryland at College Park.
Comments, suggestions and questions should be directed to
Prof. O'Haver at toh@umd.edu.
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