A method in accordance 1, wherein {HEAD ~ the ion exchange column} is {TAIL ~ a cation exchange column} 
is
A method in accordance 1 , wherein { HEAD ~ the ion exchange column } is { TAIL ~ a cation exchange column }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL