SELECTIVE FLUOROMETRIC-DETERMINATION OF INDIUM(III) BY HIGHPERFORMANCE LIQUID-CHROMATOGRAPHY WITH 2-METHYL-8-QUINOLINOL BASED ON A LIGAND-EXCHANGE REACTION OF SILANOL GROUPS

The decomposition of metal chelates due to silanol groups in the high- performance liquid chromatography (HPLC) column was applied for the se lective determination of indium(III) by HPLC. The decomposition of met al chelates developed with the ligand-exchange reaction between metal chelates and silanol groups. Among seventeen elements [Bi(III), Ca(II) , Cd(LI), Co(II), Cr(III), Cu(II), Fe(III), Ga(III), In(III), Mg(II), Ni(II), Pd(II), Pb(II), Sc(III), V(V), Y(III) and Zn(II)], only indium (III) and zinc(II) were detected with 2-methyl-8-quinolinol as a pre-c olumn derivatizing agent with fluorometric detection by using the deco mposition reaction. The fluorescent 2-methyl-8-quinolinol chelates of Cd(II), Ga(III), Mn(II), Pb(II), Sc(III) and Y(III) were decomposed by silanol groups in the HPLC column. The baseline separation between in dium(III)- and zinc(II)-2-methyl-8-quinolinol chelates were performed on a TSK gel ODS-80 column (250 mmX4.6 mm I.D.) with an eluent consist ing of 4.10(-3) mol dm(-3) 2-methyl-8-quinolinol and 2.10(-3) mol dm(- 3) hexamethylenetetramine in aqueous (20%, v/v) methanol solution. The detection limit (S/N=3) of indium(III) was 1.4.10(-8) mol dm(-3). The thermodynamic studies on the coordinating function of the silanol gro up were also discussed. (C) 1997 Elsevier Science B.V.