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