A computer assisted method for the scale up of a column liquid chromatographic separation from the analytical to preparative scale is successfully proposed to make the up-scaling process easier and faster. The test sample consisting of six phenolic compounds was chromatographed on an analytical HPLC column using two different gradient runs. Based on the chromatographic data achieved from these initial analyses, elution behaviour of compounds could be simulated for alternative conditions using the DryLab program. A simulative replacement of the analytical column with a preparative scale medium pressure LC (MPLC) column allowed the determination of gradient profile to allow sufficient separation in the preparative scale. A test run carried out in suggested simulated conditions matched well with expected elution times. Furthermore, this upscaling procedure was successfully applied to a plant extract.

DryLab is used to optimize mobile phase and temperature after evaluating chromatograms of gradient elution separations performed automatically by column switching. The automated procedure was applied to more than three dozen substances (steroidal intermediates) with a time savings of more than a third.

DryLab is used in method development with the goal of enhancing separations through the exclusive use of gradient time and column temperature. The resulting method is simple, fast, demonstrates excellent transferability and is ideal for the quantitative analysis of pigments in dilute natural water samples.

Rational selection of optimized experimental conditions for chromatographic separation of analytes is realized nowadays by means of specialized method development software. Two such programs, DryLab (LC Resources, USA, in Europe: Molnár-Institut, Berlin) and ChromSword (Merck, Darmstadt), were compared in a few aspects in this paper. The aim was to make a comparison of the quality of the software packages in the separation of neutral compounds, performed isocratically in RP-HPLC systems. A discussion of the differences in predicted and experimental chromatographic retention parameters is reported. The conclusion reached is, that the two programs provide good predictions of retention data, when predictions are based on %B changes using two initial experimental runs. An additional option of ChromSword, employing the quantitative structure-retention relationship (QSRR), did not to provide precise predictions of the separation, because molecular structural data were used as inputs. Predictions based on molecular structure were unaccurate. The comparison of the performance was only done with ca. 5% of the funtional capabilities, which DryLab was offering. Gradient data were not compared at all.

Excellent description of the mathematical background and practical aspects of HPLC gradient elution technique as a fundamental of the DryLab-software .

Development of a method for a high performance liquid chromatography (HPLC) separation can be a major undertaking. Before the separation can be made, the sample must be in a suitable form to inject, and pretreatment steps are often required to remove major interferences or materials that might shorten the column life. After conditions for adequate separation are determined, some level of method validation is usually performed. Sample pretreatment and method validation are beyond the scope of the present discussion, which concentrates on achieving separation. This article describes only the major steps that are required for most samples. For additional information, the reader is urged to consult the reference by Snyder et al. (see Further Reading) which covers HPLC method development in detail. Additional method development information can be found in the other monographs listed.