A new and very simple procedure for the differential pulse polarographic determination of ultra trace quantities of tungsten using catalytic hydrogen wave and application to tobacco sample

ÜNAL Ü., Somer G.

JOURNAL OF ELECTROANALYTICAL CHEMISTRY, vol.687, pp.64-70, 2012 (SCI-Expanded) identifier identifier


In this work a new and very simple differential pulse polarographic method is established for the trace determination of tungsten using catalytic hydrogen peak. For its determination, polarograms have been taken in various electrolytes including Britton-Robinson buffer (pH = 2.0, pH = 4.0, pH = 5.0 and pH = 6.0), nitric acid, hydrochloric acid, perchloric acid and phosphoric acid. The highest peak was obtained in the presence of 0.01 M H3PO4 + 0.1 M KCl (pH = 2.0-2.5) which appeared at -1.1 V. The effects of pH, phosphate concentration, type of electrolyte on this peak have been studied. The height of the hydrogen catalytic peak was increasing with the addition of Mo(VI). Formation of a heteropoly acid was responsible of the catalytic hydrogen peak. The best condition for the determination of 5 x 10(-8) M W(VI) was found to be 1 x 10(-5) M Mo(VI) and 1 x 10(-2) M H3PO4 + 0.1 M KCl (pH = 2.0-2.5).