Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

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Forschungszentrum Julich Gmbh

Gerd Boling

Ernst Steudle

Josef Zillikens

In an osmometric measurement device and a method for determining the content of an analyte in a solution of a mixture of substances including the analyte, the mixture solution is admitted to a conduit of an osmotic cell structure having inner and outer cells filled with an osmoticum and divided by an inner membrane which is impermeable for an analyte in the outer cell and the outer cell is separated from the conduit by an outer membrane which is permeable for the analyte but not for other substances in the solution so that the pressure generated in the inner cell is only the result of the amount of analyte permeated into the outer cell and the pressure in the inner cell is determined by a pressure measuring device in pressure transmitting communication with the inner cell and is utilized for determining the content of the analyte in the solution of substances.

Osmometric device and process for determining the analyte content of a

This invention relates to an apparatus for the selective determination of e concentration of a substance dissolved in a solvent by means of an osmosis cell. The osmosis cell according to the invention contains a substance not contained in the solution to be tested, which is either practically insoluble or is impermeable for the membrane. This substance reacts chemically with the substance permeating into the osmosis cell, with a product resulting from it in the cell or with a product resulting from the substance in the solution to be tested and permeating into the cell. Reaction products are thereby formed which produce a pressure in the osmosis cell, which is different from the osmotic pressure of the chemically converted portion of the substance. A pressure increase thereby occurs in the cell, from which the concentration of the substance in the solution to be tested can be determined on the basis of standard values.

Apparatus for the selective determination of the concentration of a

This invention relates to a process for the selective determination of the oncentration of a substance dissolved in a solvent by means of an osmosis cell. The osmosis cell according to the invention contains a substance not contained in the solution to be tested, which is either practically insoluble or is impermeable for the membrane. This substance reacts chemically with the substance permeating into the osmosis cell, with a product resulting from it in the cell or with a product resulting from the substance in the solution to be tested and permeating into the cell. Reaction products are thereby formed which produce a pressure in the osmosis cell, which is different from the osmotic pressure of the chemically converted portion of the substance. A pressure increase thereby occurs in the cell, from which the concentration of the substance in the solution to be tested can be determined on the basis of standard values.

Process for the selective determination of the concentration of a

This invention relates to a process and apparatus for the determination of he concentration of substances dissolved in a solvent. For this purpose, an osmotic cell is used, in which first, by means of an (external) reference solution, a working pressure is established, and after replacement of the reference solution by the solution to be tested, the pressure curve established in the cell is determined. The object is also to determine the concentrations of substance present in high concentration with very great absolute precision. For this purpose, an osmometer solution is selected which contains an excess of not more than 80 mOsm more than the reference solution, and in which the substances to be measured are contained in such a concentration that the difference of the concentrations of the substances in the solution to be tested and in the osmometer solution is not more than 70 mOsm. The total concentration of the substances is then determined taking into consideration the concentration of the substances in the osmometer solution. For the determination of very small deviations of the substances (less than 20 mOsm), the temperature of the solutions at the measurement point is kept constant, for which purpose there is provided an appropriate device.

Process for the determination of the concentration of substances

The invention relates to methods for the determination of the concentration of substances dissolved in a solution by means of an osmotic cell, using a pressure measurement device, and an apparatus incorporating the aforesaid osmotic cell with pressure measurement device. According to a first method, the concentrations of the substances are determined by the formation of the differences between a final pressure which is established after contact with the solution and an original and minimum pressure. According to a second method, the pressure/time course of biphasic response curves is analyzed in the vicinity of the minimum pressure, along with the rate constant for the exponential pressure increase which takes place after the minimum pressure, and the concentrations of the substances are then computed. According to a third method, simultaneous with one another, the initial slopes of the pressure/time curve of the pressure decrease in two osmotic cells are determined, and from these data, two results are determined, which are functions of the concentrations of the substances, and the concentrations of the substances are calculated from them. The reflection coefficients of both osmotic cells must thereby differ sufficiently.

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Inden-Pier, Germany

Gerd Boling