in the flow through also the above process is continued for more than 30 minutes thus simultaneously it acted as a virus inactivation step after loading the column is washed with 9 cv of 73 mm sodium acetate buffer of ph 4 8 the desired product is obtained in the flow through of the wash step as well impurities bound to the column are subsequently eluted with 25 mm tris 500 mm nacl buffer of ph 7 1 the flow through fractions from example 4 are loaded onto a q sepharose column that has been pre equilibrated with buffer containing 25 mm tris 60 mm nacl ph 7 1 the column is washed with the same buffer desired product is bound to the column and is eluted with 40 mm phosphate 280 mm nacl buffered at ph 6 0 alternatively captoadhere a mixed mode chromatographic column can be used in place of q sepharose column in this case the column is pre equilibrated with 5 cv of 20 mm phosphate buffer of ph 6 0 and washed again with the same buffer 5 cv desired protein bound to the column is then eluted with 4 cv of buffer containing 40 mm phosphate and 280.