Abstract: A pH measurement system automatically measures the pH of samples in purge and trap sample concentrators, autosamplers or other sample delivery devices. The pH measurement system includes a pH sensor that is positioned in a pH sample reservoir. The pH sample reservoir may be automatically filled with sample from a sparge vessel, calibrated using liquid having known pH, or rinsed. A controller enables and disables the valves and pump to transmit the liquid to the pH sample reservoir.

Abstract: The invention relates to a digital burette having a manual drive for suctioning and applying an adjustable dose volume, a gear unit connected downstream and a digital display device controlled thereby for setting the dose volume. The control comprises an incremental encoder which is functionally connected to the gear unit, at least one sensor for detecting the signals produced by the incremental encoder and a processor connected to the sensor and the display device for calculating the dose volume corresponding to the number of signals. The incremental encoder is, in particular, a sector disc with two groups of sectors of different magnetic field strength disposed alternately in the peripheral direction of the sector disc. A sensor detects the number of turns of the sector disc.

Abstract: A system for determining parameters and compatibility of a substance such as an asphalt or other petroleum substance uses titration to highly accurately determine one or more flocculation occurrences and is especially applicable to the determination or use of Heithaus parameters and optimal mixing of various asphalt stocks. In a preferred embodiment, automated titration in an oxygen gas exclusive system and further using spectrophotometric analysis (2-8) of solution turbidity is presented. A reversible titration technique enabling in-situ titration measurement of various solution concentrations is also presented.

Abstract: A diagnostic device for use in performing clinical tests on a fluid, including a light transmitting plate and a panel adhered to and substantially covering the plate. The panel has an opening therein formed and a strip of pH testing material, substantially smaller than the panel, is fixed between the plate and the panel to fill substantially the opening, wherein the pH testing material produces a color indicative of fluid pH upon contact with the fluid. A window formed in the panel exposes a portion of the plate wherein the panel forms a wall on the perimeter of the window to confine fluid applied to the plate, within an area defined by the window.

Abstract: The present invention relates to an improved analytical method and apparatus therefor, in particular to a method and apparatus for continuous titration in which at least one parameter of at least one compound in a text mixture may be monitored as the composition of the mixture is continuously varied.

Abstract: There is a need within the medical community for non-invasive instruments to measure critical physiologic parameters at the point of care. Such a technique may be applicable to a wide variety of commonly monitored physiologic parameters during critical care patient management. The invention is directed to a method of measuring the pH of a patient's tissue. The method includes measuring the optical signal from a specie whose fluorescence is pH sensitive, such as nicotinamide adenine dinucleotide (NADH) and also measuring the optical signal from a second biological marker, such as FAD, the fluorescence from the second marker being substantially insensitive to pH. The method includes determining the patient's pH by using the first and second optical signals.

Abstract: An analytical test cartridge is provided. The analytical test cartridge can be used for medical analyses of liquid samples removed from a patient, for example blood. The analytical test cartridge is configured to provide for titration experiments. An example of a titration experiment that can be performed with the arrangement, is titration of heparin with protamine. Methods of assembly and use are provided.

Abstract: A pH sensor system (10) and method capable of monitoring the pH level of a medium based on the characteristics of a chromatic pH sensitive material employed in the pH sensor system is provided. The pH sensor system includes at least a housing (12) having at least one transparent surface (14); a light sensitive circuitry (15), e.g., a LED (16) and photo-detector (18), enclosed within the housing; and, a chromatic pH sensitive material (20) overlaying at least a portion of the transparent surface having the characteristic of becoming saturated when an ambient pH level reaches a predetermined level such that the light sensitive circuitry detects a different intensity of incident light when the chromatic pH sensitive material is saturated than when the chromatic pH sensitive material is not saturated. As the pH level of the medium, e.g., concrete, storage tanks containing chemical reagents, etc.

Abstract: An aqueous polishing composition having abrasive particles of a metal oxide has a pH that undergoes pH drift, because ions are provided by dissolution of the metal oxide, and the pH drift is minimized by providing the aqueous polishing composition with an equilibrium concentration of the ions at said pH.

Abstract: A method and device for performing fluid analysis by separating cells and/or particles from a fluid, such as a biological, vehicular or industrial fluid. The device is a micromachined filtering device comprising a substrate with through-thickness vias having approximately equal diameters that prevent passage through the substrate of a first material while permitting passage through the substrate of other materials having diametrical dimensions less than the diameter of the vias. Electrodes are located on a surface of the substrate between vias so that as the first material collects at the surface of the substrate, the electrodes become electrically connected to produce an output signal in some proportion to the amount of the first material collected. The device can incorporate multiple micromachined substrates, yielding an analysis system that produces an electrical output for each of a number of properties or parameters.

Abstract: A system for measuring and controlling the concentration of a chemical agent in a solution has a reaction cell for receiving a sample, a titrant dropper for releasing one or more drops of titrant into the sample, a first photosensor for sensing disruptions of light for every drop of titrant released, and a controller that communicates with the photosensor and computes the concentration of the chemical agent based on the number of disruptions of light at the photosensor. The present invention also includes a method for sensing and controlling the concentration of a chemical agent in a solution. The method includes having a sample containing the chemical agent, triggering the release of a number of drops of titrant into the sample, detecting the number of drops released into the sample, and computing the concentration of the chemical agent in the sample based on the number of drops of titrant released into the sample.

Abstract: A method for the automatic monitoring and control of the content of surfactants of an aqueous process solution, wherein, under program control: a sample having a predetermined volume is taken from the aqueous process solution; the content of surfactants in the sample is determined utilizing measuring equipment capable of analyzing the sample; the results of the analysis are output by the system; the functional capacity of the measuring equipment is checked by determining the surfactant content of one or more standard solutions if the results of the analysis of the content of surfactants on two consecutive drawn samples differs by a preselected value; and corrective action is automatically taken if the check of the measuring equipment reveals any problems. Bath maintenance measures may be initiated automatically or by request from a remote location according to pre-determined criteria. The method reduces the number of staff for bath monitoring and bath maintenance and increases process safety.

Abstract: A chemical sensing system senses a concentration of a chemical of interest in a fluid. A portion of the chemical of interest diffuses across a barrier into an electrolyte. The barrier can be one or more polymeric hollow fibers. Electrodes or other sensing devices are disposed within the electrolyte. The electrolyte is selected such that it undergoes regenerative chemical reaction as it is exposed to the chemical of interest and the electrodes. The concentration of the chemical of interest can be determined by measuring a property of the electrolyte, such as current flowing through the electrolyte.

Abstract: The present invention relates to a method for determining at least one parameter of samples of physiological liquids, to test devices which may be used in the method, to a holder comprising a plurality of such test devices, and to a measuring apparatus adapted to accommodate the holder and to be used in the method and to a system comprising the apparatus and the holder.

Abstract: A test composition and device are described for determining levels of cyanuric acid in water, especially water in swimming pools and spas. The invention is especially characterized by avoiding the use of melamine as part of the test composition.

Abstract: A membrane capable of sensing gaseous phase ammonia is provided. The membrane includes a hydrophobic membrane layer that has a microporous structure and a pH sensitive dye embedded within the microporous structure such that the membrane is capable of calorimetrically sensing a change in ammonia with a high degree of sensitivity and responsiveness as applied to, for example, a change in ammonia dissolved in a dialysis solution during dialysis therapy.

Abstract: A pH sensor for the visual or optical indication of the pH of a sample. The pH sensor includes a hydrophilic, optionally intrinsically charged or neutral, synthetic membrane and at least one pH indicator dye immobilized thereto, so as to prevent appreciated bleeding of the at least one indicator dye from the synthetic membrane upon immersion in an aqueous liquid.

Abstract: An acid test kit uses an indicator paper in a transparent tube which is easily and temporarily inserted in a Schrader-valve at a compressor suction inlet of a refrigeration system. The simplicity, yet sufficient accuracy, of the kit permits several different ways of holding the paper in the tube through a friction fit. One way is to sandwich the paper between a tapered holder which is folded to provide a nose for actuating the Schrader valve. Another way is to provide the paper on or over a cylindrical member. A method for using the test kit including allowing vapor refrigerant from the system to pass through the tube to the atmosphere.

Abstract: In a pair of electrodes where a potential difference is changed in accordance with acidity or basicity of oil, a reference electrode is made of cobalt or a cobalt alloy, and a sensitive electrode is made of tungsten or a tungsten alloy. The sensitive electrode is used in combination with the reference electrode. Accordingly, it is possible to provide a pair of electrodes for detecting the acidity or the basicity of the oil which use a novel electrode material not hazardous to the environment and at the same time, suited for use in a semiconductor fabrication technique.

Abstract: To provide a simple examination method of buffer capacity of saliva without influence by examiner's subjectivity and an examination instrument to carry out suitably the examination method, an examination instrument, in which two to ten kinds of chemical liquids each containing a pH indicator having a transition interval within a pH range of 3.0 to 7.0 and capable of easily discriminating its indicated color at two or more stages and an acid in an amount so as to exhibit a different pH value within a pH range of 1.5 or more but lower than 3.0 when water in the same amount as that of saliva to be examined is added at a temperature of 25° C.

Abstract: Free fluorine is measured in a hydrofluoric acid-containing solution with a coexistent metallic ion based on a total fluorine concentration, a total acid concentration, a metallic ion concentration, the equilibrium constant of hydrofluoric acid, and equilibrium constants of metal fluoride complexes. It is possible to accurately analyze free fluorine in a hydrofluoric acid-containing solution without being affected by a coexistent metal and by the passage of time. This technique may be used to accurately control the concentration of free fluorine in a hydrofluoric acid-containing mixed acid pickling solution at the production site of a stainless steel so that improvement in descaling capability as well as reduction in the amount of chemical materials can be achieved.

Abstract: Linear or cyclic aminophosphonates are disclosed which are useful as pH markers. A method of using the linear or cyclic aminophosphonates in phosphorus-31 NMR spectroscopy is also disclosed.

Abstract: The present invention relates to a method for titration comprising guiding a sample to be titrated through a conduit, adding a reagent to said conduit at at least two entrance positions along said conduit in such a manner that said reagent will react with the sample within at least one individual sector of the conduit, defined as the space between two consecutive entrance positions or a final individual sector defined between a final entrance position and a sample exit point of the conduit, while at least one detection device positioned at the end of each sector of said conduit register the chemical and/or physical status. A pressure difference is provided between the reagent delivery device and the sample conduit such that the pressure difference measured between the reagent delivery device and the end of the final individual sector is controlled to be greater than the total pressure drop between the sample delivery point and the end of the final individual sector.

Abstract: The present invention relates to an apparatus for monitoring the progress of membrane fouling that occurs on pores as well as on the surface of a membrane by means of variations of zeta potential (&zgr;) of a hollow-fiber membrane according to time passage of filtration of a suspension, wherein colloid particles, biopolymers and other inorganic particles are dispersed, and the method thereof. Moreover, the present invention also relates to a method to identify the effect of concentration polarization layer and cake layer which can vary according to the axial position of a hollow-fiber and the developing progress of a membrane fouling by measuring the position-dependent zeta potential of the hollow-fiber membrane.

Abstract: Described is a process and electronic data processing software program for carrying out same, for the creation of a flavor or fragrance formulation or for the determination of the use of a fragrance or flavor ingredient in a fragrance or flavor formulation or use thereof in or on a perfume composition, perfumed article, cologne, foodstuff, beverage, oral care product (e.g., mouthwash) and/or chewing gum. The process uses apparatus which is a laser light beam transmitter fitted with a light scattering means having attached thereto a titration means.

Abstract: A method for determining the quantity of phenol extracted into an aqueous solution of an alkali metal hydroxide uses a measurement of the pH of the solution, from which the equivalents of phenol relative to alkali metal hydroxide in solution is determined. A method for optimizing the use of an aqueous solution of an alkali metal hydroxide in a phenol recovery process uses pH measured to regulate the feed rate of the aqueous solution.

Abstract: A test method and apparatus for determining the content of carboxylic acid-based corrosion inhibitors in a coolant or heat exchange fluid. The amount of acidic reagent added to the coolant or fluid between two pH equilibrium points is measured to determine the amount of inhibitors. The refractive index can be measured to determine the amount of freezing point depressant.

Abstract: The present invention pertains to methods and devices for detecting microbial spoilage of a food product. The method involves placing a spoilage indicator device including a barrier sheet in fluid contact with a food product. The method also involves allowing any reactant molecule of a predetermined size produced in the food product by microbial spoilage to traverse the barrier sheet to contact a carrier of the device and to react with an indicator material therein. The method further provides observing the spoilage indicator to determine whether the detectable change has occurred in the indicator material. The detectable change indicates a build-up of the reactant molecule in the food product and therefore is indicative of microbial spoilage.

Abstract: To provide an examination method of buffer capacity of saliva and an examination instrument of buffer capacity of saliva, by which the buffer capacity of saliva of a subject can be examined simply without being influenced by an amount of saliva and preciously without being influenced by the subjectivity of an examiner, an end portion of an absorptive material in a predetermined shape, containing a pH indicator at least having one or more color transition range of pH 4.0 to 7.0 and an acid, is dipped in saliva to allow the saliva to penetrate into the absorptive material, and a buffer capacity of the saliva is examined from a distance where a color to be exhibited by the pH indicator has changed by the penetrated saliva from a predetermined place of the absorptive material and a distance where the saliva has penetrated from a predetermined place of the absorptive material.

Abstract: A new method is proposed where a limited amount of MBTH is used to detect a point of interest (POI) of an aldehyde in a test sample. Preferably, it reacts with aldehyde first to form an azine. Only if there is remaining MBTH, it is oxidized to another species which combines with the azine to form formazan. However, if there is enough aldehyde, all the MBTH is converted to azine and there is no formation of blue color. Thus, by using the limiting agent MBTH to test the amount of aldehyde around the point of interest, then less aldehyde would produce more blue color and more aldehyde would produce less blue color. This method is especially useful in the quality control of aldehyde products. The end color may be different depending upon the order of addition of the reactants. For example, if an oxidizing agent and MBTH are mixed before adding the aldehyde, a light green to green/blue color results. This method could be used for solution test or for tests on a solid phase such as on nylon membrane.

Abstract: Microfluidic devices having predisposed assay components for increased throughput and prolonged shelf life are provided.

Abstract: A test method and apparatus for determining the content of carboxylic acid-based corrosion inhibitors in a coolant or heat exchange fluid. The amount of acidic reagent added to the coolant or fluid between two pH equilibrium points is measured to determine the amount of inhibitors. The refractive index can be measured to determine the amount of freezing point depressant.

Abstract: In an automated analyzer containing a spectrophotometer for determining color changes in a urine sample the urine is admixed with a basic indicator effecting the first color change and an acidic indicator effecting a second color change, a surfactant and water. The spectrophotometer determines and prints whether a first or second color change has occurred.

Abstract: A system to detect spoilage of a food product is described in this invention. The present invention can be used to see if a food product is spoiled, by mixing a part of the food product with an indicator of food spoilage within a separate transparent compartment of the food container, which is visible to the consumer.

Abstract: Continuous on-line titrations based on feedback-controlled flow and the principle of compensating errors are carried out in a titration system by maintaining a constant total flow of mixed sample and titrant. The flow of the titrant is varied in response to a controller output voltage, and accordingly, the makeup sample flow also varies but inversely to the titrant flow. A detector monitors the status of the indicator color in the mixed stream.

Abstract: A chemical indicator of an aurin moiety in a substrate to detect the presence of an oxidizing agent.

Abstract: Disclosed is a titration method for determining the concentration of a base developer solution to within ±0.02 mN, which involves performing steps (a) and (b) in any order: (a) weighing to ±0.001%, an amount of a solution of aqueous base developer of known approximate normality; (b) weighing to ±0.001%, an amount of an acid titrant sufficient to neutralize at least 90% of the base developer in the solution of step (a); thereafter performing steps (c)-(e) in the following order: (c) contacting the aqueous base developer solution with the acid titrant to neutralize at least 90% of the base developer in the solution, and leaving from about 1% to about 10% of the original aqueous base developer as residual non-neutralized base developer in the solution; (d) titrating the residual non-neutralized base developer in the solution with the acid titrant to the end point in an inert atmosphere, wherein the temperature of the titrant is maintained at a temperature of about 20-30° C.±0.

Abstract: A control device serving as a source of control reagent for a solid-phase analytical test device is disclosed. The analytical test device analyzes a biological sample for the presence of an analyte such as an enzyme or other chemical species or a particular pH range, and registers the presence or absence of the analyte as a detectable change in an indicator. The control device contains a control reagent that produces the same indicator change and that can be transferred to the analytical test device by a sample implement such as a wet swab. The control reagent is present on the control device as a dry lamina or combination of laminae. A positive control reagent on a control device in accordance with this invention mimics the action of the analyte once it is transferred to the analytical test device, while a negative control reagent on the control device mimics the action of a sample that lacks the analyte.

Abstract: The invention relates to a method for rapid measurement of acidity in juice. A sample vial is quantitatively filled with juice and transferred to a mixing vessel. A drop of pH indicator solution is added to the mixing vessel. While swirling to mix, a calibrated dropper is used to add a known concentration of titrant. The titrant is added and the number of drops that are required to cause a color change is noted. The number of drops of titrant used is multiplied by a predetermined conversion factor to generate a percent acidity value appropriate for the sample type. Different concentrations of titrant or different volumes of sample, with different conversion factors, are used, depending on the level of acidity expected in the sample. The method is rapid, with accuracy and precision comparable to traditional burette titrations.

Abstract: A test strip for confirming a desired proportion of components in dialysate, including a first medium capable of indicating the concentration of bicarbonate ion, and a second medium capable of indicating the concentration of glucose. The test strip defines a first region impregnated with the first medium, and a second region impregnated with the second medium. The test strip optionally includes a third medium capable of indicating the pH of the dialysate. The third medium is impregnated at a third region on the test strip. Alternatively, the test strip comprises a bicarbonate test pad attached to the first region, a glucose test pad attached to the second region, and optionally a pH test pad attached to the third region. The glucose test pad is impregnated with the first medium, the glucose test pad is impregnated with the second medium, and the pH test pad is impregnated with the third medium.

Abstract: The invention comprises a method for determining an analyte in which a dye solution is illuminated to induce a first and a second output light at a first and second wavelength, respectively, and the analyte concentration is determined from the measured first and second output intensities. The apparatus includes a probe (12) containing a dye solution, a light source (24), a frequency-sensitive photodetector (28) and a controller (90).

Abstract: The present invention relates to a method and apparatus for measuring the lipid peroxidation extent in biological fluids and suspensions of tissues, in which a specifically prepared lipids containing sample is exposed to heat so as to induce thermochemiluminescence light which is emitted by the sample and is enhanced to an amount which can be detected by a special purpose photo detector. The measurement of the light allows to conclude about the content of peroxides and subsequently to obtain accurate assessment of lipid peroxidation.

Abstract: The present invention provides novel microfluidic devices and methods that are useful for performing high-throughput screening assays. In particular, the devices and methods of the invention are useful in screening large numbers of different compounds for their effects on a variety of chemical, and preferably, biochemical systems.

Abstract: A method of analysis of vaginal secretions collected in an absorbent pad is disclosed. The method is effected by implementing the steps of (a) using an absorbent pad for collecting the vaginal secretions, the absorbent pad including an inner membrane for absorbing at least a portion of the secretion, the inner membrane being embedded among layers of the absorbent pad, and an external, viewable membrane including a color indicator for indicating a location of secretions absorbed by the absorbent pad according to at least one parameter being indicative of a pathological state; and (b) if the pathological state is indicated, biochemically analyzing the inner membrane at a location respective to the location of secretions absorbed by the absorbent pad for further characterizing the pathological state.

Abstract: The present invention provides a gender-indicating composition, and a method and kit for determining the gender of an unborn child. The gender-indicating composition includes thymol blue and can be in solid or solution form. The method of the invention includes a non-invasive colorimetric assay of a pregnant woman's urine. The kit includes a unit dose of the gender-indicating composition and, optionally, a color standard.

Abstract: Microfluidic devices for analyzing a plurality of compounds are manufactured for performing high throughput screening assays. The methods are used to manufacture devices that screen large numbers of different compounds for their effects on a variety of chemical and biochemical systems.

Abstract: A device for analyzing simultaneously multiple analytes in a fluid of unknown composition. The device includes a plurality of sensors, a light source for providing light to shine on the sensors, light detectors, and a processor. The sensors are exposed to a sample of the fluid of unknown composition. The plurality of sensors includes groups of sensors, each group targeting a specific analyte and including one or more sensors that contain an analyte-specific chemical that interacts more specifically with one analyte than with some other analytes to be analyzed. Each sensor in each group has a different chemical interacting with the analyte to target it. The light source shines light on the sensors of the plurality of sensors to cause light interaction with the sensors. The differences in the sensors lead to differences in the light interaction. The light detectors detects the light interaction by the sensors.

Abstract: In a process for titrating substances by adding increments of a titrant in time intervals, the course of the reaction is monitored in its approach toward the end point (EP), and the addition of titrant is controlled. At least one differential component is determined from the course of the reaction and used for controlling the addition of titrant. The process can be performed by an apparatus that includes a delivery unit for the titrant and suitable devices for performing the monitoring, differentiating and control functions.

Abstract: The effect of the pH of intracellular vesicular compartments and intracellular vesicular transport on multidrug resistance (MDR) of tumor cells is examined. The invention comprises in one aspect the treatment of MDR by administering a therapeutically effective amount of a pH modulator and/or a compound that can interfere with the vesicular transport of an intracellular vesicular compartment. Diagnostic utilities are contemplated and extend to drug discovery assays and methods for measuring monitoring the status of the onset or development of MDR, as well as the measurement of intracellular drug accumulation. Therapeutic compositions include a composition comprising a pH modulator alone or in combination with the dose-limited therapeutic agent(s), and a pharmaceutically acceptable excipient, are also contemplated.

Abstract: The present invention relates to a pH test stick, wherein by partially bonding a pH test paper to a neutral water-repelling mounting paper, a test solution is made to flow into a gap formed between an unbonded separated portion of the pH test paper and the mounting paper to thereby delay drying-out thereof, so that the color tone of the pH test paper developed by the contact with the test solution can be kept for a long time.