In Silico investigation of a post liquid chromatographic membrane extractor

Recently, a vapor permeable membrane was coupled to ion exclusion chromatography for the selective removal of volatile fatty acids. The volatile components are isolated from the acidic chromatographic eluent flowing through the lumen of the membrane tube and isolated in the annular portion of a surrounding extractant jacket flow where they are measured conductometrically. The extractor dimensions and extractant flow rate must be balanced to maintain chromatographic efficiency and improve sensitivity. The extraction process has been simulated by a series of repeated transfers between two flowing streams using experimentally measured permeation rates. Five n-alkyl carboxylic acids (formic-pentanoic acid) separated by ion exclusion are used as the test suite for generating and validating the model. The dependence of the peak broadening and concentration factor upon the various parameters, particularly the length, have been reduced to simple empirical formulas which may be used for optimization.