Abstract
A water-in-oil type emulsion containing 7-dodecenyl-8-quinolinol (Kelex-100) was prepared from 1.0 mol dm-3 HCl and a (1+2) mixture of toluene and n-heptane using sorbitan monooleate (Span-80) as an emusifier. The resulting emulsion was gradually injected into the sample solution and dispersed by stirring for 10 min as numerous tiny globules. When an iron(III) matrix was converted into the colloidal hydroxides by adjusting the sample pH to 3.5, traces of Ti(IV), Cu(II), Ga(III), In(III), and Bi(III) were selectively transported into the internal aqueous phase of the emulsion, leaving the iron matrix in the sample solution. After collecting the dispersed emulsion globules, they were demulsified and the metals in the segregated aqueous phase were determined by inductively coupled plasma-mass spectrometry. The detection limits (in μg g-1) were 0.05 for Ti, 0.08 for Cu, 0.02 for Ga, 0.01 for In, and 0.02 for Bi. The proposed method was successfully applied to the analysis of high-purity iron.
