Abstract: An ion concentration measuring apparatus for measuring the concentration of a measuring ion in a sample solution containing the measuring ion and an interfering ion having the same ionic charge number as that of the measuring ion. This apparatus comprises a first ion-selective electrode for generating a potential in response to the measuring ion, and a second ion-selective electrode in response to the interfering ion. The first ion-selective electrode is brought about in contact with a first, second and third standard solutions, each containing known concentrations of ions. A selectivity coefficient of the ion-selective electrode is calculated on the basis of the output potential of the first ion-selective electrode. The first and second ion-selective electrodes are brought about in contact with the sample solution.

Abstract: A universal standard chemical reagent for quantitative visual and spectrometric analysis of compounds having reactive functional groups, including mixtures and homologs of said compounds, said reagent comprising a compound of the general formula Q-B-f, wherein: Q stands for an organic moiety which can be measured quantitatively, visually by color, spectroscopically, or fluorometrically; B represents a non-reactive organic bridging unit linking the moiety Q to a reactive functional group f, said bridging unit being of sufficient length or size to prevent any possible interaction of Q that might alter its spectroscopic properties even upon derivatization; and f is a reactive group which can react with a compound to form covalently bonded derivatives.

Abstract: Selected polyvalent anions or cations are removed from a liquid sample stream as a pretreatment for the analysis of the liquid sample stream. A stream containing anions of interest, precipitable anions (e.g. sulfate ions) to be removed and an added displacing salt flow through a first cation exchange resin bed having precipitable exchangeable polyvalent ions (e.g. barium ions). Displacing polyvalent cation (e.g. calcium) displaces the exchangeable polyvalent ion from the cation exchange resin into the liquid sample at sufficient concentration to cause the precipitable anion and exchangeable cation to form a precipitate which remains in the resin bed and is thus is removed from the sample stream. Then the anions of interest in the soluble portion of the liquid sample stream are separated and detected. The invention is also applicable to the removal of precipitable cations (e.g. barium ions) by reversing the roles of the anions and cations.

Abstract: A reagent composition comprising (a) one or more pH buffers, (b) one or more pH indicators, and (c) one or more surfactants as a sensitizer, is suitable for measuring ionic strength or specific gravity of aqueous solution samples such as urine rapidly and precisely.

Abstract: The present method for evaluating the extent of a lithogenesis process intensity and for determining the composition of lithogenic urate salts in urolithiasis resides in adding an aqueous protein solution to a urine sample in a ratio of 9:1, 7:1 or 5:1, respectively; applying the mixture thus-prepared as a drop onto a smooth surface for drying for at least 24 hours; determining the nature of crystallization of urate salts in the marginal zone of the urine sample, the presence of separate, singly occurring crystals, conglomerates of crystals and a complete crystallization of this marginal zone being indicative, respectively, of a weak, moderate or a highly pronounced extent of a lithogenesis process intensity; the composition of crystalline formations is determined, while, simultaneously, establishing the constitution of urate salts in the central zone of that same urine sample, followed by carrying out a comparative analysis to said two compositions to determine the composition of lithogenic urate salts.

Abstract: The present invention relates to a group of organic chelators whose affinity for calcium ion in solution is decreased by electromagnetic radiation. Specifically, the chelators are related to fura-2 and utilize the addition of an azide group to the 3-position of the benzofuran ring of a fura-2 type structure. Photolysis of the azide group causes the calcium ion affinity to decrease 100 to 1000 fold. These chelators when incorporated into rat fibroblasts either by microinjection or by incubation as the membrane-permeable, enzymatically-labile esters and flash-photolyzed cause large increases in intracellular free calcium ion. These chelators are used to generate controlled fast elevation of intracellular free calcium ion concentration to mimic or modulate a number of important cellular responses, especially in nerve or muscle.

Abstract: A swab is impregnated with a test reagent such that a test for a specific substance can be effected by rubbing the impregnated swab over the surface to be tested and then viewing the swab for a reagent reaction. The swab may have a hollow stem, and within the hollow stem is a cartridge within another cartridge. An activator solution is in one of the cartridges and a reagent is in another of the cartridges. A method for testing for a substance includes impregnating a swab, and rubbing the swab over a surface suspected of containing the substance. If the substance is present in the surface, a reaction with the substance produces an easily detectable color on the swab tip.

Abstract: An improved method for diagnosing myofibrogranuloma (MFG) in walleye without harming the fish is described. Blood samples are drawn from walleye and creatinine and calcium levels are then determined along with the sex and length of the fish. These data are then analyzed and compared to data from healthy walleye using discriminant analysis. The process is effective for identifying approximately 88% of MFG-positive walleye.

Abstract: The invention provides method and kits for detecting a metallic cation in a sample of a body fluid. The preferred method and kits include the use of at least two different types of antibodies having different specificities. In the preferred method, the sample of body fluid can be contacted with an effective amount of a capture antibody specific for a naturally occurring polypeptide that can bind the metallic cation to form a first antigen-antibody complex. An effective amount of an antibody specific for an epitope on a metallic cation-naturally occurring polypeptide complex or an antibody specific for a metallic cation is added to the first antigen-antibody complex to form a second antigen-antibody complex. The amount of the metallic cation in the sample of body fluid is determined by detecting the amount of the second antigen-antibody complex.

Abstract: A device and method for testing for Cystic Fibrosis includes a sample cell having a capillary tube with a lumen that will hold approximately five microliters of sweat. The capillary tube has metallic rings around each end of the tube with an RF oscillator attached to one ring and a microprocessor attached to the other. An RF signal, which is transmitted from the RF oscillator through the sweat in the sample cell, is subsequently analyzed at the microprocessor by comparing the transmitted signal to a reference. In accordance with the comparison made by the microprocessor, the presence of Cystic Fibrosis may be detected.

Abstract: The invention disclosed relates to an agent capable of selectively binding lithium ions to form a lithium complex, employed in association with a biologically inert carrier or excipient. Typically, the agent is included in a novel graft polymer, such as a cross-linked polystyrene polymer. This invention may also be applied to sensing lithium ion concentrations in aqueous solution and to the selective removal of lithium ions from an aqueous solution, including biological fluids.

Abstract: Aqueous solutions containing buffers and electrolytes are adjusted to levels required for calibration of both blood gas analyzers and ion selective electrolyte analyzers. A control material, composed of similar matrix, is adjusted to three levels of blood gas and electrolyte conditions. These quality control materials are used to monitor blood gas/electrolyte laboratory instrumentation.

Abstract: A source of high frequency electromagnetic radiation is coupled to a specimen containing a target chemical whose presence and/or concentration is to be ascertained. Preferably the source radiation includes a plurality of high frequency spectra, at least one of which encourages energy transfer with the chemical of interest. The source radiation is coupled to the specimen via a probe pair that is also used to access a return signal representing an interaction between the source signal and the specimen. The return signal is processed to yield a spectral signature correlating to the target chemical and/or its concentration. Preferably signal processing compares frequency spectra within the source signal to spectra within a sampled return signal. The sampled return signal is a signal obtained by sampling a return signal at the probe pair and by sampling the response to the source signal of a circuit that electrically approximates the specimen.

Abstract: A system for cleaning a probe used in analytic equipment--for example, that used in analysis of body fluids--in order to reduce carry-over of materials from one sample to the next. A probe wash is provided in which the simultaneous introduction of pressurized air and water creates a turbulent flow including the use of a pressurized gas stream of short duration to blow the residue of the previous sample out of the probe prior to washing with additional diluent liquid. Also, a waste receptacle is provided which uses a filtered air vent and a liquid saturated material around the probe receiving opening to prevent the escape of aerosols from the receptacle.

Abstract: The indicator compounds of the present invention are substituted or unsubstituted BAPTA-type chelators that contain a benzazolyl-coumarin substructure, and the pharmaceutically acceptable non-toxic salts and esters thereof. These compounds are useful for the detection and quantification of polycationic metal ions, particularly Ca.sup.2+.The compounds of the invention have the core structure ##STR1## or the structure ##STR2## where m=2 or 3 and X can be S, O, or C(CH.sub.3).sub.2. The above core structures are optionally substituted by substituents that alter the binding affinity of the indicator, shift the spectral properties of the indicator, or act as a reactive site for the preparation of a variety of conjugates.

Abstract: A process and a reagent for the determination of ions in fluids, wherein the influence of these ions on the activity of an enzyme is measured. The ions for example are sodium, potassium, calcium, magnesium, manganese, lithium, lead, zinc, copper, iron or other heavy metals or non-metallic ions comprising chloride, bicarbonate, protons, ammonium and substances that give rise to ammonium. The enzymes which are used may be a transferase, a hydrolase, an oxidoreductase or a lyase. An essential feature is a method to exclude interferences by ions by masking the interfering ions with a binding agent.

Abstract: The present invention relates to chemical sensor and biosensor probes for measuring low concentration of metals and metal ions in complex samples such as biological fluids, living cells, and environmental samples. More particularly the present invention relates to a gel-based Indo-1 and Fura-2 chemical sensor probes for the measurement of low concentrations of calcium, cadmium, magnesium and the like. Also disclosed is a detector device using the sensors of the present invention.

Abstract: The present invention provides novel reagent compositions incorporating chlorophosphonazo III and a chelating agent and methods utilizing such compositions for the determination of magnesium and magnesium concurrently with calcium in an analytical sample as well as diagnostic test kits for such determinations.

Abstract: A luminescence-optical indicator for determining the activity of alkali metals based on decay time includes at least three components that are chemically bound to one another, i.e., a fluorophor, a functional group with which the luminescence decay time of the fluorophor can be influenced, and a ionophor binding the alkali metal ions to be measured in a selective and reversible manner, the effect of the functional group on the decay time of the fluorophor being altered in dependence on the activity of the alkali metal ions.

Abstract: The present invention provides a method for preparing and storing biological samples prior to measuring ionized Mg.sup.2+ concentrations in order to obtain accurate and reproducible readings. A novel method for accurately reading ionized magnesium ion concentrations in biological samples is provided. A method for monitoring ionized Mg.sup.2+ concentrations and ionized Ca.sup.2+ :Mg.sup.2+ ratios in a patient, useful in diagnosing and prognosing disease states including cardiopulmonary bypass surgery, hypertension, abnormal pregnancy, head trauma, and fetal abnormalities is provided as well as a composition and a method of treating a patient with ionized Mg.sup.2+ or ionized Ca.sup.2+ and Mg.sup.2+.

Abstract: Methods of assaying for the presence or amount of a metal ion in a sample suspected of containing such ions. In one aspect, an enzyme amplified sandwich assay is provided which relies upon the ability of the analyte (metal ion) to form a complex with two complexing agents (chelators). In this assay, the first sandwich chelator is immobilized on a solid support, while the second sandwich chelator is linked to a reporter group (e.g., an enzyme). This assay combines the specific recognition of the analyte by the first and second sandwich chelators with the great signal amplification offered by the reporter group (e.g., enzyme). In another aspect, a competitive assay is provided that relies on the competitive inhibition of complex formation between the coating ligand (i.e., the chelator attached to the solid support) and the organometallic compound attached to the reporter group (e.g., enzyme) by the metal ions of interest present in the sample.

Abstract: Novel fluorogenic and chromogenic three-dimensional ionophores are provided which selectively bond ions such as potassium, sodium, and lithium, even in neutral aqueous or alcohol media. The novel ionophores comprise an "ion-recognizing system" fused to a "signal-moiety" through one or more heteroatoms having a non-bonded electron pair. The signal-moieties are selected from the group consisting of fused ring heterocyclics, fused aromatics, and subsituted aromatics having at least one nitro or azo moiety. The ion-recognizing system is a three-dimensional cryptand. The ionophores are ideal for the selective and direct termination of ions in biological or environmental samples and the like.

Abstract: The invention is to continuously measure the contents of trace ingredients such as alkaline metal contained in combustion gas with high precision. An oxidizer and fuel are supplied into a flue line to form a flame, while a part of the combustion gas is introduced to the flame for inducing light emission. The contents of metal ingredients in the gas are calculated based on the intensity of the emitted light. Since a flame forming device is installed in the flue line without any additional equipment such as a sampling line, and such the contents of trace ingredients in the gas are calculated based on the intensity of the emitted light, the contents of the trace ingredients can be measured with high precision. Quickly responsive monitoring and control are assured.

Abstract: The present invention is a method for analyzing silicon for nonmetallic contaminants. The method comprises: (A) forming an alloy comprising silicon and a metal which promotes separation of nonmetallic contaminants present in the alloy, (B) separating the nonmetallic contaminants from the alloy, and (C) analyzing the separated nonmetallic contaminants for chemical content. The present invention is particularly useful for analyzing metallurgical grade silicon intended for use in the direct process for the production of organohalosilanes for the presence of oxides and carbides of calcium, aluminum, and silicon.

Abstract: An optical absorbance method for the quantitative determination of Lewis acid decomposition products in nonaqueous electrolytes.

Abstract: Diluents and methodologies for determining the concentration of total calcium in a clinical sample (e.g. whole blood, sera plasma urine cerebro spinal fluid) containing protein-bound calcium are disclosed. Methodologies include the steps of: (a) admixing the sample with a diluent, the diluent including effective amounts of a pH buffer and at least two agents capable of complexing free calcium in the sample, where the agent-calcium complex association constants ("log K" in base 10) each have a range from about 1.5 to about 7.0; and (b) contacting an aliquot of the diluted sample with a calcium-specific ion selective electrode. The response of the calcium-specific ion selective electrode is an indication of the concentration of total calcium in the sample.

Abstract: The present invention concerns a method of detecting hemolysis in a whole-blood sample, a method of determining an elevation in the potassium ion concentration of a whole-blood sample, an apparatus for detecting hemolysis and/or determining an elevation in the potassium ion concentration in a fluid sample, an apparatus for detecting hemolysis and/or determining an elevation in the potassium ion concentration in a whole-blood sample, and a single-use cartridge containing a plurality of microfabricated biosensors which further contains a hemolysis detection unit.

Abstract: A target-specie responsive regulation of water treatment agent feed is achieved by the monitoring of a subject target-specie indicator. A target specie in a sample taken from the system is selected as the subject target-specie indicator, or instead an incipient reagent is added to the system sample to form a subject target-specie indicator. Such a formed subject target-specie indicator comprises a combination of the incipient reagent and a target specie. The subject target-specie indicator might then monitored by fluorescence analysis of the sample to determine at least one fluorescence emission value that can be correlated to the in-system concentration of the target specie. In combination with an inert tracer, the system consumption for the target specie can be determined. A responsive adjustment of the in-system concentration of a water treatment agent can be made.

Abstract: Fluorescent, calcium-binding probe compounds having visible-light excitation and emission wavelengths, and a method of usage for these probe compounds in making wavelength-ratiometric or intensity-ratiometric measurements of calcium ion concentration in samples. The probe compounds generally relate to a heterocyclic part as bonded to a Ca.sup.2+ binding unit, namely, BAPTA, via an ethylenically unsaturated group; preferred examples of the heterocyclic group include benzothiazole, naphthothiazole, thiaflavin, indolenine, chloroindolenine, methoxybenzothiazole, and methoxyindolenine.

Abstract: A process for rapidly and conveniently measuring the magnesium concentration of a biological fluid, such as blood or urine, is carried out by fixing amounts of a chelatometric dye, metal cation masking agents, a chelating agent, an alkaline buffer, and a stabilizer on a bibulous material covered with a semipermeable membrane, adding the test specimen, and measuring the amount of color change of the dye at a selected wavelength. The amount of color change is proportional to the quantity of magnesium in the original specimen and can be measured by visual comparison to a standard color chart or with a dedicated reflectance photometer. Furthermore, a method is given for expanding the range of linearity. The method for making the dry indicator includes coating bibulous material with a reaction solution which is dried thereon, followed by coating this material with an organic solution which is dried thereon.

Abstract: A method of separating strontium from a sample of biomass potentially contaminated with various radionuclides. After the sample is reduced, dissociated, and carried on a first precipitate of actinides, the first precipitate is removed to leave a supernate. Next, oxalic acid is added to the supernate to cause a second precipitate of strontium and calcium. Then, after separating the second precipitate, nitric acid is added to the second precipitate to cause a third precipitate of strontium. The calcium remains in solution and is discarded to leave essentially the precipitate of strontium.

Abstract: A phenol derivative obtained by reacting a carboxylic acid anhydride with a phenol compound, followed by condensation with iminodiacetic acid and formaldehyde, or a salt thereof is effective as an agent for adjusting color forming sensitivity in a colorimetric analysis of metal ions in a fluid such as a living body fluid.

Abstract: A composition, method and test device for determining the divalent cation concentration or estimating the specific gravity of a test sample are disclosed. The method utilizes a test device comprising a test pad, wherein the test pad includes a carrier matrix incorporating a reagent composition capable of interacting with divalent cations present in the test sample to produce a detectable and measurable response that correlates to the divalent cation concentration or to the specific gravity of the test sample. The reagent composition, comprising a metal-sensitive triphenylmethane dye; a buffer; an optional chelating agent; and suitable carrier, is incorporated into a carrier matrix to provide a test pad of a device useful in a divalent cation assay or a specific gravity assay of a test sample.

Abstract: Assay methods are provided for determining the presence of lithium in high sodium content liquids such as serum, plasma, urine or other sample without deproteinization. The novel compounds are water soluble derivatives of TMC-crownformazans and provide signal enhancement by increased absorbance of the dye-lithium complex over the dye anion.

Abstract: A method, composition and test device for the semiquantitative determination of specific gravity of a test sample are disclosed. The method utilizes a reagent composition capable of producing a detectable and measurable response that correlates to the concentration of cations, and therefore the specific gravity, of the test sample. The reagent composition comprises: a) a polyvalent metal ion having a valence of at least two, like mercuric ion or calcium ion; b) an indicator capable of interacting with the polyvalent metal ion to provide a polyvalent metal ion-indicator complex having a first color; c) a buffer; and d) a suitable carrier. The reagent composition is used in a wet phase specific gravity assay or is incorporated into a carrier matrix, like filter paper, to provide a test pad useful in a dry phase specific gravity assay of a test sample, such as urine.

Abstract: Disclosed are arylazo chromoionophores characterized by the formula: ##STR1## wherein X is hydrogen or a monovalent cation, Y is H or methoxy and R is a ringed aromatic organic structure which affects the optical absorption properties of the compounds. Also disclosed is a method for the detection of calcium ion using these compounds.

Abstract: A method, composition and test device for the semiquantitative determination of specific gravity of a test sample are disclosed. The method utilizes a reagent composition capable of producing a detectable and measurable response that correlates to the concentration of cations, and therefore the specific gravity, of the test sample. The reagent composition, comprises: a) a complexing agent, like a polyelectrolyte, an ion exchange material or a chelating agent, such as a copolymer of maleic acid and methyl vinyl ether; b) a polyvalent metal ion having a valence of at least two, like ferrous ion or cobaltous ion; c) an indicator capable of interacting with the polyvalent metal ion to provide a color transition, like calmagite or gallocyanine; and d) a suitable carrier. The reagent composition is used in a wet phase specific gravity assay or is incorporated into a carrier matrix, like filter paper, to provide a test pad useful in a dry phase specific gravity assay of a test sample, such as urine.

Abstract: A test device and method of determining the presence or concentration of a predetermined ion, such as a cation of medical interest, like sodium, potassium, calcium, magnesium or lithium, in an aqueous test sample are disclosed. The test device includes a test pad comprising a hydrophilic indicator reagent composition capable of interacting with a predetermined ion, or electrolyte, to produce a detectable or measurable response. The hydrophilic indicator reagent composition consists essentially of a hydrophobic ion specific ionophore, a hydrophobic reporter substance, and a stabilizer polymer such as gelatin. The hydrophilic indicator reagent composition, either as a film or layer, or after incorporation into a suitable carrier matrix, provides a test pad of sufficient sensitivity to the predetermined ion to achieve an accurate and trustworthy electrolyte assay of an aqueous test sample, such as plasma or serum, by a dry phase test strip assay.

Abstract: An indirect potentiometric method and diluent for the analysis of lithium are disclosed. The diluent includes effective amounts of a pH buffer and a non-cationic surfactant comprising at least one hydrophobic group, at least one hydrophillic group and being substantially free of polyoxyethylene groups. Most preferably, the pH buffer is tris-(hydroxymethyl) aminomethane-phosphate, and the surfactant is 2, 4, 7, 9-tetramethyl-5-decyn-4,7 diol. An indirect potentiometric determination of lithium in a clinical sample comprises the steps of mixing the sample with a diluent, contacting an aliquot of the diluted sample with a lithium specific ion selective electrode and at least one ion selective elctrode specifically responsive to a monovalent interfering ion, and measuring both the response of the lithium specific ion selective electrode and the monovalent interfering ion specific ion selective electrode, the responses being an indication of the concentration of lithium in the sample.

Abstract: A process and apparatus are disclosed for the demineralization of ground bone particles or pieces of cancellous or cortical bone. The apparatus includes multiple solution reservoirs which supply solutions to be pumped into one or more columns filled with bone samples to be demineralized. Solvent outflowing from the column(s) can be monitored for pH, calcium ion concentration or conductivity as a basis for determining when demineralization is complete. During the delipidization phase of processing, lipid solute can be monitored by photometry, or a small assay of the eluent can be dropped into deionized water to see whether a precipitate develops. Flow through the apparatus, including the types and amounts of solutions to be flowed through the apparatus, can be manually or computer controlled.

Abstract: A chromogenic compound found to be especially selective in the determination of calcium in blood of the general formula (I): ##STR1## where: R is hydrogen or lower alkyl;X is CH.sub.2, CH.sub.2 CH.sub.2, CH.dbd.CH, O, S, SO.sub.2, S--S, or NR;X is CH, C--OH or N;M is p-nitrophenylazo, 2,4-dinitrophenylazo, 2,4,6-trinitrophenylazo, p-nitrostyryl, p-benzoquinoneimino, bis-(4-dimethylaminophenyl) hydroxymethyl, 3-phenylisothiazolyl-5-azo, thiazolyl-5-azo, or isothiazolyl-5-azo;k is 1;l is 0 or 1; andn is 0 or 1.

Abstract: A method for the quantitative determination of one or more chemical parameters of a sample medium employs a fluorescent agent which is not responsive to the parameter to be determined and which has an excitation spectrum and an emission spectrum, and a closely adjacent chromogenic agent which responds to the parameter of the sample medium to be determined by a change in its absorption spectrum the emission spectrum of the fluorescent agent at least partically overlapping the absorption spectrum of the chromogenic agent. The absorption maximum of chromogenic agent is shifted in accordance with the parameter to be determined, causing a reduction of fluorescence decay time t in the fluorescent agent, thereby enabling quantitative determination of the chemical parameter with improved long-term stability and infrequent calibrations.

Abstract: 1,5-Bis(2-hydroxyphenyl)-3-cyanoformazans substituted in at least one of the 3-, 4- and 5-positions of either phenyl moiety are useful for the determination of magnesium ions. The cyanoformazan substituents are chosen such that their cumulative Hammett-sigma value is greater than about 0.23. These cyanoformazans are useful in analytical compositions and methods for either wet or dry assay of magnesium ions.

Abstract: A colorimetric, particularly spectrophotometric, method and compositions for determining calcium levels in blood serum in the presence of magnesium and other serum ions is described. The method uses an aqueous composition with a pH between about 7.5 and 10 with arsenazo III to complex calcium and a hydroxyquinoline selected from the group consisting of 8-hydroxyquinoline and 8-hydroxyquinoline-5-sulfonate to complex magnesium. Lipase and a cyclodextrin can be used as reagents to clear triglycerides in the serum which can provide turbidity and false results in some instances. The method is particularly useful for human serum.

Abstract: (a) An alkanolamine solution containing anions, a conductance probe connected through a meter to a recorder and a stirrer are provided in a container, (b) the solution is stirred at a constant rate and metering and recording of the conductance of the alkanolamine solution are initiated, (c) an anion exchange resin in the OH.sup.- form is then introduced to the container in an amount in excess of that required to exchange all anions from the amine solution, (d) the conductance of the alkanolamine solution is monitored until steady state is reached, and (e) the total anion content and the sodium content (if present) are determined from the conductance trace.The process and apparatus may be used to display conductance changes with time and rate of conductance changes with time in order to determine which anions are present in the alkanolamine solution, whether or not sodium is present and the magnitude of conductance values at various time intervals.

Abstract: Novel compounds and assay methods are provided for determining the presence of lithium in serum, plasma, urine or other sample without deproteinization. The novel compounds are water soluble derivatives of TMC-crownformazans and provide signal enhancement by increased absorbance of the dye-lithium complex over the dye anion.

Abstract: Tissue damage may be quantified, tissue type identified, neural activity monitored or blood hematocrit determined by measuring the difference between the total tissue sodium and potassium concentrations in the area in question. Comparison of these measurements with standard values permit evaluation of the amount of tissue damage in cells of the same type or the tissue type in non-necrotic cells. Evaluation over time of normal brain cells permit monitoring of neural activity. By directly and simultaneously measuring sodium and potassium ion concentrations, for example, a nuclear magnetic resonance spectrometer can image areas of different tissue type in differing colors. In this manner tumors and lesions can be clearly delineated. Measurement of total potassium concentration of a blood sample and the potassium concentration of the cell-free plasma will permit determination of cellular volume fraction (hematocrit).

Abstract: The subject matter of the present invention are naphthol derivatives having the general formula I ##STR1## in which R.sup.1, R.sup.2, R.sup.3 are the same or different and each represents hydrogen, an alkyl or alkoxy group, in which at least one of the residues is a (C.sub.8 -C.sub.30)-alkyl or alkoxy residueR.sup.4 is hydrogen or an alkyl groupR.sup.5 is a nitro group, an alkyl group substituted by halogen, a cyano group, a sulfonamide group or an alkylsulfonyl groupX is nitrogen or the residue CR.sup.6 andY is sulphur or the residue CR.sup.7 =CR.sup.8in which R.sup.6, R.sup.7, R.sup.8 are the same or different and each denotes hydrogen, halogen, a nitro group, a cyano group, an alkyl or an alkyl group substituted by halogen or an alkylsulfonyl group, a process for their production and their use as a pH indicator or in methods and agents for the determination of an ion in an aqueous liquid.

Abstract: A method of determining individual ion concentrations in mixtures using ion exchange separation combined with indirect photometric detection and frontal analysis.

Abstract: A novel 14-crown 4-ether derivative is disclosed for use in a dry analytical element for assaying lithium.