Improvement of Silica Gel Column Chromatography and Construction of Automated Analyzer for Nonionic Mixtures

A method for the separation of the components of a nonionic mixtures by adsorption column chromatography was developed.Some silica gels for size exclusion chromatography showed characteristic features when applied to adsorption chromatography. They hold high polar components very weakly and release them quite easily, thus making good recovery possible. Resolution, however, was not sufficient from a practical standpoint.A new separation system for nonionic mixtures was developed using two columns, one packed with Fractosil 1000 (silica gel for size exclusion chromatography; Merck) and the other with Silica Gel 60 (for adsorption chromatography; Merck). A mixture containing non-polar to very high polar components such as PEG # 6000 could be separated with good resolution and recovered quantitatively using 7 eluents, selected so as to optimize the system. Switching the column-connection order corresponding to the eluents also ensured good results.Furthermore, an automatic separator was constructed for rapidly separating nonionic mixture. Typical components separation could be achieved automatically, in 4.5 hours, by this separator, whereas a conventional method, for example, that proposed by Newburger et al., requires more than ten hours to complete the same separation.