Extraction is effected by equilibrating homoionically saturated ion exchange resin beads with {TAIL ~ a sample} of {HEAD ~ the complex matrix} under study 
Extraction is effected by equilibrating homoionically saturated ion exchange resin beads with { TAIL ~ a sample } of { HEAD ~ the complex matrix } under study
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH