Test device for an optical determination of cations, anions or electrically neutral ionogenic species, and test method using said device

摘要

A test device is described, by means of which the presence or concentration or activity of cations, anions or electrically neutral ionogenic species can be determined by a variation of the optical properties of this test device. The device includes at least one cation-selective lipophilic ionophore, combined with at least one anion-selective lipophilic ionophore or a component which acts as cation exchanger or at least one anion-selective ionophore in combination with a cation-selective lipophilic ionophore or a component which acts as an anion exchanger, in each case at least one of these components varying its optical properties as soon as the test device comes into contact with the cation or anion or the neutral ionogenic species to be determined. In an appropriate test, anions and cations pass simultaneously from the substantially aqueous test solution into the organic phase of the test device, or an ion exchange takes place between cations of the test solution and cations of the test device, or anions of the test solution and anions of the test device, and at least one of the ions entering the test device is complexed there by the corresponding ion- selective lipophilic ionophore. The extent of the variation of the optical properties of the test device is equivalent to the concentration of the ion to be determined, an ion competing with it or a counter-ion formally forming a salt with the ion in question.