This construction also allows the use of {TAIL ~ filters} to remove particulates before the sample reaches {HEAD ~ the chromatographic medium} 
This construction also allows the use of { TAIL ~ filters } to remove particulates before the sample reaches { HEAD ~ the chromatographic medium }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD