Polarography with Slowly Forming Mercury Drops

Abstract

BY means of a capillary greatly restricted in the stem but with an orifice radius of 108 µ, it has been found possible to study current – time and current – voltage curves for single mercury drops with ordinary polarographic equipment—a Cambridge polarograph with photographic recording. Drop-times in a given solution could be varied between 16 sec. and 8 min. and were reproducible. The drop-weight in 0·1 N potassium chloride was about 28 mgm. The results show the change in character of current – time curves at constant voltage as the voltage is altered, give accurately measurable values for current – time relations during cathodic reduction, and indicate a new use for the polarograph in quantitative analysis by reason of the appearance of non-suppressible maxima on current – voltage curves.