The ability to rapidly detect a trace amount of {HEAD ~ lead species} on {TAIL ~ site} is very desirable 
on
The ability to rapidly detect a trace amount of { HEAD ~ lead species } on { TAIL ~ site } is very desirable
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH