Synthesis of spherical macroporous epoxy-dicyandiamide chelating resin andproperties of concentration and separation of trace metal ions from samples

A novel spherical macroporous epoxy-dicyandiamide chelating resin is synthe sized simply and rapidly from epoxy resin and use for the preconcentration and separation of trace Ga(III), In(III), Bi(II), Sn(IV), Pb(II), V(V) and TI(IV) ions from solution samples. The analyzed ions can be quantitatively concentrated by the resin at flow rate of 3.0 mi min(-1) at pH 3, and can a lso be desorbed with 10 ml of 4 M HCl + 0.2 g thiourea from the resin colum n with recoveries of 97-100%. The chelating resin is reused for eight times , the recoveries of these ions are still over 92%, and a 100-1000 times of excess of Fe(III), AI(III),Ca(II), Mg(III), Ni(II), Mn(II), Co(II), Cu(II), Zn(II) and Cd(II) cause no interference in the determination of these ions by inductively-coupled plasma atomic emission spectrometry. The capacities of the resin for the analytes are in the range of 0.66-4.20 mmol g(-1). Th e results show the relative standard deviation for the determination of 50. 0 ng ml(-1) Ga(III), In(III), Bi(III), Sn(IV) and Pb(II); 5.0 ng ml(-1) V(V ) and Ti(IV) are in the range of 1.2-4.0%. The recoveries of a standard add ed in real solution samples are between 96 and 100%, and the concentration of each ion in mineral sample detected by the method is in good agreement w ith the certified value. (C) 2000 Elsevier Science B.V. All rights reserved .