The use of computer simulation software for high-performance liquid chromatographic (HPLC) method development is considered. In particular, gradient elution data entered into DryLab G/plus are used to predict isocratic retention times. The motivation was to establish whether data generated in a research-grade, gradient environment might be used to simulate accurately isocratic HPLC conditions applicable to a process monitoring operation. Good agreement between experimentally obtained and computer-predicted retention times for a homologous series of alkylketones was found for the conversion from gradient to isocratic elution conditions.

DryLab G software was used for the optimization of gradient elution programs in reversed-phase high-performance liquid chromatography applied to the chromatographic analysis of flavonoids present in marsh-mallow (Althaea officinalis). The optimization experiments were carried out for a mixture of eight standard solutes (isolated previously from the plant) and then applied to an extract from the flowers of marsh-mallow. Computer simulation experiments allowed convenient analytical conditions to be chosen. The use of two modifiers, methanol and acetonitrile, made the identification of separated components more certain. Good agreement between simulated and experimental chromatograms was obtained.

Rapid development of robust and reliable high-performance liquid chromatographic methods for routine quality control of Ginkgo biloba is possible with computer simulation. The goal is to reduce method development time and to increase transparency of the complex composition of plant extracts. With only two basic experiments and a peak tracking process based on the total area ratio compared to the individual peak-area ratios a robust method with more than 50 simulated experiments was completed in 8 h. The best method has been verified experimentally. The correlation between the best simulated run and the final experiment was satisfactory.

The use of computer simulation for developing optimized gas chromatographic (GC) separations is illustrated for several samples. Resolution maps (plots of Rsvs. heating rate r) for different starting temperatures provide a means for the rapid exploration of separation as a function of the temperature program in the case of programmed-temperature GC. Isothermal separations are easily developed by trial and error, because of the speed of computer simulation. More complex samples may require multi-ramp temperature programs, t

Computer-simulation with commercially available software (DryLab GC) allows the prediction of isothermal or temperature-programmed gas chromatographic (GC) separation as a function of experimental conditions. In either case, two experimental runs are carried out initially, using a linear temperature program (heating rate different, all other conditions the same). Data from these two runs are entered into the computer, and separation can then be predicted for other conditions: different temperatures in the case of isothermal runs, or any kind of temperature program for programmed runs.

The reliability of resulting predictions was evaluated in the present study for several samples and a wide ranger in separation conditions. Retention time predictions were usually accurate within a few percent, and sample resolution was predicted within about ± 10%. The use of computer simulation should be a considerable help for the rapid development of superior GC methods.

Several different samples and three stationary phases of varying polarity have been examined for changes in band spacing as a function of temperature. The results of these studies have been expressed as a relative variability in the temperature coefficients of retention (S) for adjacent bands. A theoretical analysis suggests that useful changes in band spacing vs. temperature (or heating rate) can be expected when the difference in S values (ΔS) for two bands is larger than 1 to 2%. The samples studied exhibited variations in average values of ΔS of 0.6–6%. This suggests that optimizing the (isothermal) temperature or (programmed) heating rate of a gas chromatographic separation will often be advantageous.