a) placing {HEAD ~ an aliquot} of {TAIL ~ sample} onto a test element comprising, in overlying relation, 
of
a ) placing { HEAD ~ an aliquot } of { TAIL ~ sample } onto a test element comprising , in overlying relation ,
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH