The immobilization of octamethyl-14-crown-4 onto crosslinked polymer supports is reported and the selectivity for Li(I) from aqueous solutions quantified. The amount of Li(I) complexed by the crown ether is affected by the polarity of the polymer matrix: Complexation increases with increasing matrix hydrophilicity. Poly(glycidyl methacrylate) is the preferred support matrix for the crown ether. (c) 2005 Elsevier Ltd. All rights reserved.