The extractable material is removed by first dissolving it in {HEAD ~ a liquid} which is not {TAIL ~ a solvent} for the matrix forming material to form a solution 
is not
The extractable material is removed by first dissolving it in { HEAD ~ a liquid } which is not { TAIL ~ a solvent } for the matrix forming material to form a solution
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH