Abstract
This investigation was undertaken to develop coulometric titration with externally generated reagents. Determination of niobium with externally generated manganese(III) ion was studied.
The electrolyte composed of 0.4N manganese sulfate and 6N sulfuric acid, was introduced into an externally generating cell, manganese(III) ion being gnerated with constant current electrolysis. Niobium which had been reduced with zinc amalgam was titrated, using potentiometric end point detection. The maximum anodic current density was 5 mA/cm. Micro quantities of niobium from about 0.3 mg to 2 mg were determined with an average error of about 1%.
The method was applied to the determination of niobium in stainless steel.
