Countercurrent chromatography: Ito's solvent classification analysed with Boolean experimental designs

The setting up of an analytical Countercurrent Chromatography (CCC) instrum ent involves many variables. Experimental designs were used to study the re tention of the liquid stationary phase in the chromatographic column. The i nfluence of five factors was analysed, but no clear conclusions could be dr awn from the experimental results analysed with the classical regression mo del generally used with experimental deigns because several high-order inte ractions remain without explanation. In contrast, the same results analysed using a Boolean experimental design gave a good explanation of the behavio r of each of the three types (Ito's classification) of solvents. High-order interactions were explained and the right settings of the instrument has b een obtained to satisfy the running experimenter's needs. As an application of Boolean designs, a special setting of the instrument w as determined to obtain the highest possible retention with a particular ki nd of solvent. In this case, it has been found that there is one practical setting for low-density mobile phases and one another for high-density mobi le phases. (C) 2001 Elsevier Science B.V. All rights reserved.