Coulometric microtitration of arsenic(III) and isoniazid using a vitreous carbon generating electrode

A small-scale coulometric titration cell and apparatus is described in which a vitreous carbon rod anode is used to generate bromine. The amount of the latter required to titrate from 3 to 15 µg of arsenic(III) or isoniazid with a precision of 2 per cent. is found by using an integrating digital milliammeter. The titration end-points were obtained by use of a form of differential electrolytic potentiometry.