Abstract: An improved 3-pole membrane electrode for polarographic measurements in which an auxiliary electrode is defined having an arc which is generated by rotation about the center point of a disc-shaped working electrode. A preferable liquid junction form of reference electrode is located in the sector defined by the arc of the auxiliary electrode and the center point of the working electrode; and an analyte permeable membrane is intimately conformed over the sensing face of the improved polarographic electrode.

Abstract: An apparatus and method are described for automatically correcting drift in automatic titrations, such as coulometric titrations of water. An endpoint detector provides a signal indicative of the state of the titration mixture and the detector signal is monitored by two comparators, responsive to titration mixture states on opposite sides of the endpoint and connected to means for controlling forward and back titration. At the end of a titration, the titration time and amount of titrant are stored in memory elements, and circuitry including an array of gates monitors the comparator signals during two post titration time periods to determine both the direction and rate of drift, and to correct the titration results for the amount of drift detected.