Use of a Hanging Mercury Drop Electrode in the Alternating Current Polarographic Analysis of Thallium(I)

Abstract
The use of a hanging mercury drop electrode (HMDE) in the a.c. polarographic determination of thallium was studied systematically. Analysis was carried out by scanning anodically the potential of HMDE from the limiting-current potential region at a constant scanning rate and by measuring the a.c. peak-height for the anodic stripping process of thallium. Thallium could be concentrated effectively on the HMDE at the initial stage of this procedure and then stripped anodically. By employing this technique, a marked increase in sensitivity could be obtained and 1.0×10−6 m thallium(I) in an EDTA solution was determined accurately. The interference effects of lead, cadmium, zinc, and indium on the determination of thallium were also investigated. When the electrolysis was initiated in the limiting-current potential region of lead(II), the peak-height of thallium was found to be enhanced markedly.