Abstract
Chemical vapor generation (CVG) producing volatile species of zinc was carried out in a custom made generator with high-resolution continuum-source atomic absorption detection. The influence of composition of the reaction medium and various reaction modifiers was studied.
The optimum conditions included neutral to basic pH of the reaction mixture, i.e., 0.1 M HCl and 0.5% (m/v) NaBH4 prepared in 0.1 M NaOH. Substantial improvement of generation efficiency (approx.18-times) was achieved with 8-hydroxyquinoline and a LOD of 4 ng mL(-1) was obtained.
The overall CVG efficiency of 2.7% was determined by comparison of sensitivity obtained with CVG and conventional solution nebulization (both coupled to inductively coupled plasma mass spectrometry) and 2.5% was determined by employing a radioactive isotope (65)Zn. The described method is reasonably resistant to interferences, the greatest interference effect was observed with Bi(III) and Fe(III), other transition and noble metals interfered at a 100-times surplus over Zn and their effects decreased in the order Co(II) > Ni(II) > Cd(II) > Mn(II) > Ag(I) > Cr(III) > Cu(II).
The accuracy of the method was verified by determination of zinc in the certified reference materials NIST 1643f (fresh water) and ERM CA713 (waste water).