Adsorption Behaviour of Ester and Ketone Homologues in the Electric Field Applied Liquid Crystal Column

Abstract

Previously we had reported an adsorption phenomenon which occured in the electric field applied liquid crystal (EF-LC) columns. However, any clear elucidation of the adsorption mechanism could not have been provided. Here, in order to study the mechanism further, the adsorption behaviour of series of ester and ketone homologues was investigated by using separation column-EF-LC column connecting modes. For all homologues, the relationships between carbon numbers and the adsorption amount showed U-shaped curves: The adsorption amount decreased first and showed minima, then it increased with increasing in the carbon numbers of solutes. The phenomena were discussed on the basis of the relation of the properties of liquid crystal with the structure of solute adsorbed. Then, the adsorption behaviour among the isomers of ketones and aldehydes was also studied. Their behaviour was compared with isomers of butanol, pentanol and butyl acetate which were described elsewhere. It was concluded that structural contribution, especially that from carbon skeleton, to the adsorption was independent of other factors such as types of functional group, the structure of liquid crystal molecule and so on. Therefore, if the carbon skeleton except functional group of the solute was the same, similar trends on the adsorption resulted.