Abstract: Electrode arrangement with liquid-metal electrode of controllable surface, comprising a liquid-metal reservoir, a capillary connected thereto through a controllable valve and contact means being in electric contact with the liquid-metal in the capillary. According to the invention at least one section of the capillary is formed within a metal body not reacting chemically with the liquid-metal, said metal body constituting the contact means. Preferably, the metal body is formed so that an elastic closing element of the valve fits to a surface of the metal body surrounding an opening of the capillary section formed therein.

Abstract: The invention relates to a capacitive measuring element intended for continuous measurements of conductance in streaming solutions. The essence of the measuring element is that in the measuring space the surfaces limiting it are covered by an electrically insulating material. A method for obtaining the dimensions of the measuring element has also been proposed. According to the measuring element of the invention the measurements of concentration from very low values with high accuracy and low noise level are possible. The life duration and the reliability of the measuring element are high, and it shows a high resistivity against corrosive media to be measured.

Abstract: The invention relates to a new process for the preparation of highly accurate and stable silver-silver salt reference electrode. According to the invention a homogeneous mixture is formed from silver powder and a powdered silver salt, then a paste is prepared by blending the mixture with a liquid binding agent capable of adhering to metals, applying the paste onto the surface of an electrode base, allowing the paste to harden and then subjecting the electrode to a heat treatment between 100.degree. C. and 250.degree. C. In this latter step a porous silver-silver salt layer is formed on the metal base, which renders the electrode highly accurate and stable.Ion selective measuring electrodes are prepared essentially in the same manner with the difference that silver is replaced partly or entirely by graphit.

Abstract: The invention relates to a process of and equipment for a selective, quick and accurate analysis of liquid samples. According to the process of the invention a liquid or a gas sample absorbed by a liquid is allowed to flow at a constant volume rate and overtitrated with an amount of a reagent adequate to the measurement in a definite time. Then the flow of the reagent is decreased to zero in a definite time, meanwhile continuously following, in a known way, the changes occurring in the reaction mixture. The determination of the concentration is carried out by comparing the time elapsed between the appearances of the two chemical equivalence points with calibration curves prepared with standard solutions, said time having a well defined functional relationship with the concentration of the sample.