Peaks corresponding to the specified components in the chromatogram are identified, and presences and {HEAD ~ absences} of {TAIL ~ these specified components} in the sample are thereby determined 
of
Peaks corresponding to the specified components in the chromatogram are identified , and presences and { HEAD ~ absences } of { TAIL ~ these specified components } in the sample are thereby determined
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH