Study on Anodic Stripping Polarography with the Balanced Head Stationary Hanging Mercury Drop Electrode

Abstract

Fundamental studies for the application of anodic stripping method to practical analyses have been done by use of the balanced head stationary hanging mercury drop electrode (BHMDE). Dependence of stripping peak current (l_p^a) on the experimental variables satisfied the following relation : I_p^a.∝r₀²C_R∝D^2/3C⁰tr₀^-1ν^-1/6.ω². The relationship between l_p^a and pre-electrolysis potential has been examined for 1×10^-6M Cu, Bi, Pb, Cd, In and Zn in supporting electrolytes of several kinds.The effect of the surface active substance on the stripping polarogram has also been examined. As for practical application, Pb and Cd in zinc metal and Pb, Cd and Zn in potassium chloride reagent have been determined. Anodic stripping polarography has been recognized to be very useful in the determination of micro-amounts of metal ions in solution and a number of reports had appeared during the last decade, for instance, on the structure of electrode assembly, the processes of electrode reactions and basic problems for the application of this method to practical analyses.The author has previously reported a new type of the hanging mercury drop electrode, “Balanced head stationary hanging mercury drop electrode” (BHMDE), which has been proved to have excellent reproducibility of the mercury drop size . Further, it is easy with this electrode to control the size of the electrode by selecting the duration of mercury run-off. For the application of the BHMDE to the anodic stripping method, the author has examined the fundamentals in voltammetric analysis with the BHMDE, i.e., the dependence of anodic stripping current on the radius of the electrode, the stirring velocity during pre-electrolysis, the potential and the period of presence of surface-active substances. Experimental results and an example of the application is presented in this paper.