Abstract: An optical method for quantitative determination of human serum albumin (HSA) in biological liquids such as urine is based on the observation that the absorption and fluorescence of certain anionic cyanine dyes possessing a terminal cyano group and having the general formula ##STR1## are strongly affected by HSA. This approach is distinctly more sensitive than existing techniques, allowing the detection and quantization of micro-albuminuria (i.e. detection of HSA in the 1-10 mg per liter concentration range) at costs which are distinctly lower than those for existing immunological assays. It is also much more specific for HSA than existing assays based on dye binding. Because the dyes has long wave absorptions and emissions, use can be made of electro-optical components based on semiconductor technology.

Abstract: Due to the size of the devices used for the excitation and measuring of light, conventional sensor elements for optically determining the concentrations of substances contained in gaseous and liquid samples, featuring an indicator layer with one or more indicator substances, are not well suited for use with microanalysis equipment, nor are they easy to mass-produce. These disadvantages are eliminated by integrating on the carrier layer (1) at least one photosensitive element (3) and its electric contact leads in planar arrangement, and by establishing optical contact between the indicator substance (7, 7') of the indicator layer (6) stimulated by the excitation radiation (11), and the photosensitive elements (3).

Abstract: In order to improve the response behavior of an optical sensor for determining at least one parameter in a liquid or gaseous sample, the sensor including a substrate which is provided with carrier particles and a fluorescent indicator immobilized thereon, the substrate is configured as a polymer film transparent to both excitation and emission radiation, and the individual carrier particles carrying the fluorescent indicator in immobilized form are bonded with only part of their surface to a thin layer of a thermoplastic material adhering to the polymer film and assume thermosetting properties after the carrier particles have been pressed in, whereas the other part of the surface of the carrier particles extend into an optically transparent hydrogel layer which covers the thermoplastic layer and in which the carrier particles are anchored mechanically. Such sensors may easily be attached to the end of an optical waveguide and may be made in any size by a simple punching operation.

Abstract: For the simultaneous measurement of two parameters of a liquid or gaseous sample, in a fluorescence measuring device in which the influence of the aging processes of the indicator substance and the fluctuations in the light intensity of the excitation light source are to be avoided, it is proposed that the change in the first parameter to be measured is obtained from the change in the ratio of two intensity values, determined for different wavelengths of the excitation and emission spectrum of the indicator substance, and the change of a second parameter is obtained from the change in the decay time t of the fluorescence radiation of the same indicator substance from the group of aromatic hydrocarbons, the aromatic heterocycles and the metal organic complexes.

Abstract: In order to improve a one-way measuring element, which may be inserted into an analyzer for analyzing gaseous or liquid samples and which comprises a measuring channel with a measuring zone and one or more sensors located therein, the proposal is put forward that the one-way measuring element be provided with a sensor part whose measuring channel has seals on both ends, and with a sample-taking part, and that a coupling element be placed at the inlet end of the measuring channel for direct coupling of the sample-taking part containing the gaseous or liquid sample, and that the measuring channel be filled with a calibrating and storage medium prior to the measuring process, and that the calibrating and storage medium contained in the measuring channel be displaced by the sample flowing in after the sample-taking part has been coupled to the sensor part. The one-way measuring elements obtained in this way are characterized by great simplicity of design and ease of handling.

Abstract: Due to the size of the devices used for the excitation and measuring of light, conventional sensor elements for optically determining the concentrations of substances contained in gaseous and liquid samples, featuring an indicator layer with one or more indicator substances, are not well suited for use with microanalysis equipment, nor are they easy to mass-produce. These disadvantages are eliminated by using a unitary sensor element having a carrier layer, at least one photosensitive element with electric contact leads in contact with the carrier layer, and an indicator layer containing an indicator substance.

Abstract: An ion-selective electrode for determining an electrolyte concentration in an aqueous solution includes an ion-selective layer and a potential-sensitive fluorescent indicator in the ion-selective layer, the fluorescence intensity of the potential-sensitive fluorescent indicator being measured to provide an indication of the electrolyte concentration.

Abstract: In order to obtain a higher measuring accuracy and better selectivity in the optical quantitative analysis of sulphur dioxide in gaseous or liquid media, it is proposed that the medium to be analyzed be brought into contact with a fluorescent indicator which emits fluorescent light upon excitation and which is from the group of triphenylmethane dyes, and that the extent to which fluorescence is quenched by the SO.sub.2 quencher be used as a measurable variable for quantitative determination of the content of sulphur dioxide in the medium.

Abstract: Compounds of formula ##STR1## wherein X is long-chain alkyloxy, long-chain alkylamino or long-chain dialkylamino,M is alkali metal, pyridinium or ammonium,Y is hydroxy or long-chain alkyloxy,which are especially useful in photometric and fluorimetric investigations of lipids and lipid-water interactions and of cationic biomolecules such as nicotine adenine dinucleotide.

Abstract: One measurement each is obtained from two optical sensors of ion concentration, following which the measured values are used for empirical determination of the ionic strength of an electrolytic solution. The sensors contain the same indicator substance but differ with regard to surface modification, thus ensuring different responses to ionic strength in spite of identical excitation and fluorescence wavelengths and the resulting simplicity of the optical system.

Abstract: Compounds of the formula ##STR1## wherein Y is ##STR2## M is hydrogen, or an alkali metal or ammonium ion, X is --O-- or an amino group,R is H, Cl, Br, CN or carbamoyl,R.sup.1 is H or --SO.sub.3 H, andA is one of several particular organic radicals,are especially useful in the photometric or fluorimetric determination of phosphatase or sulphatase activity in a liquid sample.

Abstract: For the simultaneous measurement of the concentrations of several substances a number of fluorescence measurements corresponding to the number of substances to be tested are performed using at least one fluorescent indicator which is non-specific relative to at least one of the substances to be tested, each fluorescent indicator having different quenching constants with regard to the individual substances quenching its intensities.From the known, unquenched fluorescence intensities of the fluorescent indicators employed, the quenched fluroescence intensities obtained by measuring, and from the quenching constants that are known, or rather, have been determined beforehand by graphical methods or calculation, the concentrations and/or concentration ratios of the individual substances are obtained.