Abstract: A method and apparatus for determining electrochemically active components in a process stream. The method comprises the steps of providing a sample in which the components are contained, and depositing the components onto a working electrode, altering the environment of the working electrode so that it is immersed in a supporting electrolyte by effecting a matrix exchange and stripping the deposited electrochemically active components from the working electrode into the supporting electrolyte. The method and apparatus utilize a measurement cell which comprises a vessel (10) for containing the supporting electrolyte and a mercury drop electrode (150).

Abstract: The invention pertains to a method and apparatus for the electrochemical analysis of solutions which comprises the measurement of an electric signal between a mercury column in a capillary and a reference electrode which are in contact with the analyzed solution sucked into the capillary. The mercury column in the capillary pulsates during the measurement. Current or voltage may be measured as the electric signal. An apparatus for the analysis of microliter volumes of solutions comprises a vessel for the analyzed solution provided with an inlet and outlet of the analyzed solution and a reference electrode, one end of a capillary is connected to the vessel for the analyzed solution and the other end of the capillary is connected to means for suction and ejection of mercury. A pulsator is attached to the capillary for moving the column of mercury and an electric contact is built into the capillary in contact with the mercury column.

Abstract: An analytical apparatus for determining the cryolite concentration in a cryolite-alumina electrolysis cell. The apparatus uses a reference electrode comprising a solid oxygen electrolyte tube containing a reference electrode of a cryolite melt supersaturated with alumina. A measuring electrode is combined with such a reference electrode to provide a potential representative of alumina concentration in the alumina electrolysis cell.

Abstract: The invention relates to an improved and highly sensitive method of electroanalytical determination of electrochemically active compounds in solution. The invention comprises a pulsating mercury drop to obtain polarographic, voltametric (coulometric), potentiometric, and anodic stripping measurements, and other measurements derived therefrom. According to the invention, a pulsating mercury drop is extruded from a capillary tube into an electrochemical solution to be evaluated, and its electrolytic current or potential is measured against a reference electrode. The method provides that mercury is extruded from the capillary (and the size of the drop is increased) and then it is withdrawn back into the capillary (and the drop is decreased to its original size), so that the drop pulsates at a frequency of 0.1 to 100 cycles/second.

Abstract: An electrochemical concentration cell adapted for immersion in a melt of aluminum-magnesium alloy for determining the concentration of the Mg on an ongoing basis (e.g., during demagging). The cell includes a first probe comprising a housing having a cavity therein containing a Mg-ion-rich molten salt electrolyte. An opening in the housing exposes the electrolyte to the melt via a porous ceramic frit wetted by the electrolyte. A hollow capsule containing a Mg-rich reference material is immersed in the electrolyte and the reference material electrically coupled to the melt via second probe immersed therein. Containment of the reference material within the capsule beneath the melt prevents attack of the housing by the reference material and evaporative loss thereof.

Abstract: A hanging mercury drop electrode is described which makes use of a capillary tube with an inverted-U shape, removably fastened to an air-tight pressure-resistant cylindrical mercury reservoir. The capillary tube has a sufficiently thin inner diameter (0.35.times.10.sup.-2 to 0.5.times.10.sup.-2 cm) and a sufficient length (40 to 50 cm) such that the viscous forces prevent mercury from flowing through the capillary tube, once a height of the mercury head is selected (1 to 2 cm) which roughly counterbalances the back-pressure acting on the drop surface. To increase the drop size, a pressure higher than the atmospheric pressure is transmitted to the mercury reservoir from a pressure generator via an electromechanical valve, which is controlled by a timer or a microprocessor. The drop becomes stationary as soon as the mercury reservoir is connected with the outer atmosphere via another electromechanical valve.

Abstract: The present invention relates to an automatic cell for polarographic analysis. According to the invention said cell comprises a vessel (14) containing a nebulizer (3) for deaerating the sample to be analyzed, the deaerated sample being accumulated into a collector (16) and conveyed to a polarographic cell (15) provided with means for the removal of the sample after its analysis. The automatic polarographic analyzer is characterized by the very short time required for its analysis.