Heyrovsky circuit of derivative polarography

Abstract

In Heyrovsky circuit for derivative polarography, a current corresponding to ΔE always flows through the recording meter, and when the zero point of recording meter is adjusted, the value of ΔE is altered.
The Heyrovsky circuit was therefore improved as shown in Fig. 3. The experimental results obtained with the circuit of Fig. 3 were as follows.
(1) The recording meter does not remove its zero point on application of ΔE potential, after the bridge circuit is balanced.
(2) Under a satisfactory state of balance, the pulse current with dropping mercury electrode disappears, if the drops of two mercury electrodes are synchronized.
(3) The derivative polarogram recorded by this circuit shows a symmetrical curve against maximum potential. This maximum potential is in good agreement to the half wave potential, if IR drop and recording lag of the recorder are corrected.
(4) The values of peak current are generally reproducible to ±1.6% difference, and they are strictly linear function of the concentration.