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620. SIMUL: A General Program for the Simulation of
Chromatograms Using the Theoretical Plate Model
by Martin Jung, Institute for Organic Chemistry,
University of Tübingen, W-7400 Tübingen, Germany
For all solutes, theoretical plate numbers and
retention times are input as a basis for the correct
simulation of peak widths and retention. The number of
solutes is not limited, and they may be injected in
different amounts and have different theoretical plate
numbers. The solutes are "injected" into the mobile
phase of the first plate, then equilibration between
mobile and stationary phase takes place, the solutes
are allowed to perform reactions among each other, and
finally the mobile phase is shifted forward to the next
plate and so on. Reactions during chromatography are
allowed and treated strictly separately from the rest
of the program in the subroutines REACT1 to REACT5. In
the program SIMUL, these subroutines simulate the
racemization of the enantiomers 1 and 2 during
chromatography with different rate constants for mobile
and stationary phase, but SIMUL can also be used for
the simulation of "normal" chromatograms if the rate
constants of racemization are entered as zero. By
modifying only the subroutines REACT1 to REACT5, the
program can easily be adapted to other problems
concerning reactions during chromatography.
This has been done in the program SIMULX which is
identical with SIMUL except for these subroutines.
Here, an example is presented as to how to describe a
more complicated system using the Runge-Kutta method
for the calculation of the reaction kinetics: The
enantiomers R and S undergo dimerization so that, in
addition to monomeric R and S, the (diastereomeric)
dimers RS, RR and SS may be present.
The chromatograms are output in a digitalized form.
The program REDUCE reduces the size of the output file
to a reasonable amount of data (about 20-100 Kb per
chromatogram), since the original output files may be
very large, depending on the theoretical plate numbers
entered.
At this point it is suggested that one transfer the
chromatogram files to a personal computer and use
commercial software for the plotting. Additional small
conversion programs will be needed to adapt the files
to the format of the particular program to be used. It
is, however, hardly possible to use the simulation
program itself on a PC, since the calculations would
take much too long. The CPU time needed greatly
depends on the theoretical plate numbers which
determine the number of loops needed.
NOTE:This program uses a feature which, while not
totally uncommon, is somewhat unusual. It
contains FORTRAN statements which are longer than
72 columns. This is important for two reasons:
* We can only distribute it in VAX COPY
(ANSI D) or TAR format.
* The user has to be aware of the above
feature and inform the FORTRAN compiler of
the use of the extended line in order to
obtain a successful compilation.
Lines of Code: 2332
FORTRAN (CONVEX)
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