Spectrophotometric and amperometric determination of tellurium (IV) by allylthiourea

The interaction of tellurium (IV) with allylthiourea has been studied by means of spectrophotometric and amperometric titration methods. The optimal conditions for chemical and electrochemical process have been determined. Voltamperometric characteristics of the components in reactions – Te (IV), ATU have been studied against sulfuric and hydrochloric acid backgrounds to choose appropriate of the potential providing significant diffusion current. It is necessary to mention that the reagents give anodic oxidation waves at + 1.2 – 1.4 V potentials. Thus it is possible to carry out amperometric titration within + 0.2 – 0.4 V range by reducing of Te (IV), while at + 1.2 – 1.4 V by oxidation current of the reagents. Amperometric titration of Te (IV) by ATU has been carried out both in cathodic and anodic fields. The diffusion current values were established rapidly, molar ratios between the interacting components are as follows: Te (IV) : ATU = 1 : 4. The conformity with amperometry main law is adhered for 1,5·10^-3 – 2,0·10^-5 mol/l solutions of Te (IV). New experimental techniques of spectrophotometric and amperometric titration of Te (IV) by the above ATU have been elaborated on the basis of experimental data described. Allylthiourea has been applied for determination of tellurium (IV) in standard solutions. Relative deviation values do not exceed 4.32 percent