Apparatus and method for the determination of substances in solution suspension or emulsion by differential pH measurement

摘要

Analyzers determine the concentration of a test substance by measuring the change of pH in a sample liquid after reaction of the test substance with a reactant. The analyzers have a tube connected between first and second microcapillary pH electrodes. In a first embodiment, the tube functions as a reaction chamber by having a reactant immobilized on a wall of the tubing or confined within the tubing. In a second embodiment, the reactant and test substance are mixed upstream relative to the first and second microcapillary pH electrodes, with the tubing serving as a delay circuit for a kinetic measurement. Output signals of the microcapillary flow-through electrodes are used to determine a change in pH, the change in pH being indicative of the concentration of the test substance.