Separation of amino acids by recycling free flow electrophoresis

The recycling free-flow electrophoretic separation of amino acids has been investigated experimentally and theoretically. An electrophoretic apparatus with dimensions of 200 x 120 x 1mm and 20 fraction collectors has been constructed. Experiments in separation of p-amino benzoic acid and histidine have been performed to test the behavior of the apparatus in the isoelectric focusing mode. The experimental results have shown that amino acids can be effectively separated under some acceptable operating conditions. Simultaneously, a mathematical model under an assumption of the quasi-steady state has been presented and solved numerically. The theoretical analysis enables us to describe the concentration change of each species in the fraction collectors quantitatively and to select reasonable operating conditions.