{HEAD ~ A method} of use includes contacting {TAIL ~ an analyte} and a preconcentrator, allowing the analyte to adsorb to the preconcentrator and then desorbing the analyte 
includes contacting
{ HEAD ~ A method } of use includes contacting { TAIL ~ an analyte } and a preconcentrator , allowing the analyte to adsorb to the preconcentrator and then desorbing the analyte
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH