Experimental evaluation of commercially available semi-permeable membranes for use with parallel-plate dialysers in flow injection systems

Abstract

Mass transfer in on-line analytical parallel-plate dialysers was studied in the continuous and flow injection (FI) modes in order to characterise the nature of the dialysis process and its dependence on experimental variables. A number of different semi-permeable membrane surfaces were evaluated in the laminar-flow and plug-flow configurations. The fraction of analyte transferred from the donor to the acceptor stream depends on parameters such as type of membrane used, membrane surface, membrane line-length, membrane porosity, concentration of analyte in the donor stream, the use of concurrent and countercurrent flow between the donor and acceptor streams, and flow-rates of the donor and acceptor streams. The dialysis of calcium and chloride ions, in the absence of protein, was studied with different membrane types and dialysers with different dimensions in continuous flow and FI, and the influence of the above mentioned parameters on the dynamic dialysis process of these ions is described.