Abstract
C18-Bonded glass beads are applied to the preconcentration and spectrophotometric determination of traces of iron as the bathophenanthroline complex. Iron (II) is treated with bathophenanthroline at pH 3.0 and the solution is passed through the column packed with the glass beads. Next, a mixture of ethanol and dimethylsulfoxide is passed through the column to elute the adsorbed complex. 1.5 ml of the colored fraction in the eluate is collected and is made up to 2 ml with ethanol. And the absorbance is measured at 534 nm. Iron involved from 0.6 to 5μg in 150 ml of sample solutions is determined with satisfactory precision. Large amounts of Zn(II), Cr(III), Mg(II), Ca(II), Pb(II) and Mn(II) do not interfere with the determination. More than ten-fold of Cd(II), Ni(II), Co(II) and Cu(II) somewhat interfere for determining 3 μg of iron. Addition of thiourea is effective to eliminate the interference from large amounts of copper. Other popular adsorbents such as Amberlite XAD-2 and XAD-7 are tested for the same purpose. In the case of XAD-7, the adsorbed complex is not eluted at all. When XAD-2 is used, more than 2 ml of the eluent is needed for complete elution of the complex.
