Statistical methods, preparative chromatography

Statistical process control methods are applied to preparative chromatography for the case where cut points for the effluent fractions are determined by on-line species-specific detection (e.g., analytical chromatography). A simple, practical method is developed to maximize the yield of a desired component while maintaining a required level of product purity in the presence of measurement error and external disturbances. Relations are developed for determining tuning parameters such as the regulatory system gain. 

Statistical process control methods are applied to preparative chromatography for the case where effluent cut points are determined by online species-specific detection. In particular, Equation 14 (with the quantity in... 

Cross-validation is conducted when two validated bioanalytical methods are used within the same study or submission, for example, ELISA assay to Biacore and ELISA to a liquid chromatography/mass spectrometry. It is recommended that test samples (spiked and/or pooled incurred samples) be used to cross-validate the bioanalytical methods. Data should be evaluated using an appropriate predefined acceptance criteria or statistical method [12,13]. It should be cautioned that many times the methods that are being cross-validated may not have the same range of quantification. In these situations, it is necessary to prepare spiked samples within the range that are common to both methods for comparison. 

The important difference between the statistical mixture design and the PRISMA method is that the former yields a computer-assisted optimum solvent composition whereas the latter relies on structured trial and error. In TLC, the PRISMA method is a viable alternative because the time to prepare and evaluate each solvent composition is small and several different compositions can be evaluated simultaneously with several development systems. The PRISMA is also very powerful for the selection of mobile phase in over-pressured layer chromatography. 

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