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