Computer simulations chromatography

W. Markowski and K. L. Czapiriska, Computer simulation of the separation in one- and two-dimensional tliin-layer chromatography hy isocratic and stepwise gradient development ,/ Liq. Chromatogr. 18 1405-1427 (1995). 

Bier, M Mosher, RA Palusinski, OA, Computer Simulation and Experimental Validation of Isoelectric Focusing in Ampholine-Free Systems, Journal of Chromatography 211, 313, 1981. Bier, M Palusinski, OA Mosher, RA Saville, DA, Electrophoresis Mathematical Modeling and Computer Simulation, Science 219, 1281, 1983. 

Alternative Chromatographic Columns Commercial radial-flow chromatography (RFC) columns first appeared in the mid-1980s. RFC is an alternative to the conventional axial-flow chromatography for preparative- and large-scale applications. In a RFC column, the mobile phase flows in the radial direction rather than the axial direction. Computer simulation proves that RFC is somewhat equivalent to a pancakelike axial-flow column [Gu, in Flickinger and Drew (eds.). 

Jackson, C., Computer simulation study of multi-detector size-exclusion chromatography of branched molecular mass distributions, /. Chromatogr. A, 662,... 

Jackson, C. and Yau, W. W., Computer simulation study of multidetector size-exclusion chromatography. Flory-Schulz molecular weight distribution, in Chromatographic Characterization of Polymers, Hyphenated and Multidimensional Techniques, Provder, T., Barth, H. G., and Urban, M. W., Eds., American Chemical Society, Washington, D.C., 1995, chap. 6. 

Patapoff, T. W., Mrsny, R. J., and Lee, W. A., The application of size exclusion chromatography and computer simulation to study the thermodynamic and kinetic parameters for short-lived dissociable protein aggregates, Anal. Bio-chem., 212, 71, 1993. 

Beck, T.L. and Klatte, S.J., Computer simulations of interphases and solute transfer in liquid and size exclusion chromatography. Unified Chromatogr., 748, 67, 2000. 

Wikstroem, M. and Ohlson, S., Computer simulation of weak affinity chromatography, J. Chromatogr.,... 

Computer-aided experimentation in counter-current reaction chromatography and simulated countercurrent chromatography (with B.B. Fish and R.W. Carr). Chem. Eng. Sci. 43,1867-1873 (1988). 

The first [5] super-cyclodextrin whose nano-sized cyclo-pentameric array is held only by a mechanical bond was synthesized by the pentakis-azo coupling of a new hermaphrodite monomer with 2-naphthol as a stopper, isolated by chromatography, and characterized by MS, 2D NMR, and visible spectral methods with the help of computer simulation [60], Cyclic pentamer (as red film, 15% yield) accompanied with the corresponding monomer (20%) (Figure 22) was obtained. 

Free energies of activation for the enantiomerization of a series of iV-aryl-1,3,2-benzodithiazole 1-oxides 41 have been determined by dynamic high-performance liquid chromatography (DHPLC) on a chiral stationary phase <1999JOC1483>. From a comparison of experimental and computer-simulated chromatograms, the barriers to stereoinversion at sulfur were found to be around 80 kj mol 1 and relatively insensitive to effects from substituents in the iV-aryl group. 

Dimensions Electron microscopy intrinsic viscosity measurements size exclusion chromatography computer-assisted molecular simulations, comparison with CPK models atomic force microscopy electrophoresis neutron scattering. 

The basic principle of one-column process is identical to four-zone SMB. The performance of the process for the amino acids separation was compared with four-zone SMB by computer simulation using Aspen Chromatography. The system and operating parameters are listed in Table 1. It was set that T2, T3 and T4 are initially filled with desorbent and T1 is empty in the simulation. Liquid in each tank is ideally mixed. Liquid of the average solute concentration in a tank is introduced into the column. The simulated concentration profile of two amino acids in the one-column process is presented in Figure 3. 

Computer Simulation Study of Multidetector Size-Exclusion Chromatography... 

A computer simulation of size-exclusion chromatography-viscom-etry-light scattering is described. Data for polymers with a Flory-Schulz molecular weight distribution (MWD) are simulated, and the features of the different detector signals are related to the molecular weight and polydispersity of the distribution. The results are compared with previously reported simulated results using a Wesslau MWD. 

R I. Prougenes, D. Berek, and G. R. Meira, Size exclusion chromatography of polymers with molar mass detection. Computer simulation study on instrumental... 

C. Jackson and W. W. Yau, Computer simulation study of size exclusion chromatography with simultaneous viscometry and light scattering measurements, J. Chromatogr. 645 209 (1993). 

Automation allows batch chromatography to be run as a continuous process. Multiple injections using a separate pump and fraction collection provide an opportunity for continuous unattended operation. In iso-cratic separations, sample injection is often made before previously injected product elutes from the column, thus reducing cycle time and solvent consumption. Continuous and automated processes are always used with smaller columns and lower amounts of expensive enantioselective stationary phases. One of the future goals for modern PHPLC optimization would be the creation of software that would allow computer simulation modeling of nonlinear effects in preparative chromatography. 

We have recently developed a gas-phase ion chromatography technique and applied it to carbon cluster cations " " and anions""". A pulse of mass-selected cluster ions is injected into a high-pressure drift cell filled with 2-5 torr of helium. The ionic mobilities of different isomeric structures depend on their different collision cross-sections with He, and the isomers are therefore separated while drifting through the cell, under the influence of a weak electric field. The absolute value of the ionic mobility for a given cluster together with computer simulations often allows unambiguous determination of the cluster... 

To operate SMB chromatography a lot of parameters (column diameter, column length, total column number and number of columns per section, eluent, feed, raffinate, extract and recycle fluid flow and switch time interval) have to be chosen correctly. Therefore, design and process optimization should be done by computer simulations. It is much more difficult to optimize SMB during nonlinear conditions as compared to linear conditions. In fact, empirical approaches for optimization during overloaded and non-linear conditions are in most cases even impossible [96, 97], Computer-assisted optimization is therefore especially important for chiral separations since these CSPs have in general lower saturation capacities compared to non-chiral columns (see paper III). 

Computer Simulation of Elution Behavior of Probes in Inverse Gas Chromatography... 

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