In order to separate amino acids whose isoelectric points (IP) are near to each other (taking proline and serine as example)

a multistage electrodialysis process was developed.In the experiment

the influences of number of stages

current intensity and concentration of NaOH on separation efficiency were investigated.The results showed that it was feasible to separate near IP amino acids by using multistage electrodialysis.Increasing the number of stages could obviously improve the purity of proline product

while have little effect on the purity of serine product，increasing current intensity could improve the purity of proline product

while have less effect on the purity of serine product.A proper amount of NaOH in the feed was helpful to the separation.