Perfluorobutanesulfonic acid
Perfluorobutanesulfonic acid ( PFBS ) is a chemical compound with a four carbon fluorocarbon chain and a sulfonic acid functional group . 
<triplet> Perfluorobutanesulfonic acid <subj> chemical compound <obj> instance of <triplet> fluorocarbon <subj> carbon <obj> has part <triplet> sulfonic acid <subj> carbon <obj> has part