Antioxidant sensor

FIELD: analytical chemistry.

SUBSTANCE: sensor can be used for inspecting level of oxidants and antioxidants in liquid. Device for detecting absence or presence of reduction-oxidation reactive-capable analyzed matter in water sample has electro-chemical cell with sensor chamber, first and second electrodes, hole for introducing sample into sensor chamber and reagent placed inside sensor chamber. Electro-chemical cell is designed to be removable after usage in any unique experiment. Reagent is capable of subjecting to reduction-oxidation reaction directly with analyzed matter to generate electric signal indicating absence or presence of analyzed matter. Method of detecting level of reduction-oxidation reaction-capable matter is also proposed as well as method of measurement of sulfur dioxide in sample of vine and method of producing device mentioned before.

EFFECT: improved precision.

36 cl, 4 dwg

 

The scope of the invention

The present invention relates to a device and method for measuring the level of the analyte, which represents an oxidant or antioxidant in the sample fluid. The device contains a replaceable electrochemical cell containing a reagent capable of directly undergo redox reaction with the analyzed substance.

Background of the invention

The oxidation reaction is defined in a broad sense, includes the transfer of one or more electrons from one molecule or atom (reducing agent or reducing agent) to another (the oxidizing agent or oxidant). Oxidation reactions are carried out in a large number of systems, for example in food, living organisms in drinking water, and can be harmful or useful. Food in contact with oxygen, may be subject to oxidative degradation, which leads to the generation of undesirable flavors and odors, to the destruction of fat-soluble vitamins and essential fatty acids, as well as to the appearance of toxic degradation products. Useful oxidation reactions in foods include reactions between natural or synthetic antioxidants and oxidants that prevents the participation of the developer in harmful oxidation reactions.

Thus, in many areas it is desirable to be able to measure levels of oxidant or antioxidant in the sample fluid. For example, is desirable from the viewpoint of quality control during production, as well as health monitoring, level measurement preservatives such as sulfur dioxide, wine or food, the level of ascorbic acid in fruits, vegetables, beverages and biological fluids and level of chlorine or peroxides in the water. It's best that these tests were quick and easy to use, and were adapted for use in field and laboratory conditions.

Existing methods for measuring these components require for successful use of the method or expensive laboratory devices, or experienced operators. For example, a sensor for detecting agents-antioxidants in the oil are described in U.S. patent 5518590. However, this sensor is not designed for only a single use and not using oxidation-reduction agent. It is, therefore, desirable to have a sensor designed for a single, one-time use, which can be used to detect the levels of oxidant or antioxidant in the sample liquid by using a redox reagent.

The essence of the image is the shadow

Provides an apparatus and method for measuring the analyzed substances, representing oxidants and antioxidants, with replaceable sensor element suitable for single use, which can be combined with the meter to implement a clear, fast and easy to use test that can be used both in the field and in the laboratory. In particular, the method of using an electrochemical sensor, which uses a redox agent that interacts with a target substance of interest, obtaining electrochemically detected signal.

In one variation of the embodiment provides a device for detecting the presence or absence of redox reactive analyte in an aqueous sample, and the device includes an electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent contained within the touch of the camera, and the electrochemical cell constructed replaceable after use in a single experiment, and when this reagent is able to undergo redox R the shares directly from the analyzed substance generating an electrical signal indicating the presence or absence of the analyte.

In one aspect of the present variant embodiment of the first electrode is a touch electrode, which may consist of platinum, palladium, carbon, indium oxide, tin oxide, gold, iridium, copper, steel, or mixtures thereof. The first electrode may also be made of silver. The first electrode may be formed using such methods as sputtering, deposition from the vapor or gas phase, screen printing, thermal evaporation, inkjet printing, ultrasonic spraying, slot coating, gravure printing, and lithography.

In another aspect of the present variant embodiment of the second electrode is a counter-electrode. The second electrode may include a metal in contact with a metal salt, for example silver in contact with silver chloride, silver in contact with silver bromide, silver in contact with silver iodide, mercury in contact with chloride mercury (I) or mercury in contact with sulphate of mercury (I). The second electrode may also be a reference electrode.

In another aspect of the present variant embodiment of the electrochemical cell additionally includes a third electrode, such as electrode. The third electrode may include a metal in contact with a metal salt, such as silver in contact with the chloride is elebra, silver in contact with silver bromide, silver in contact with silver iodide, mercury in contact with mercury chloride (I) and mercury in contact with sulphate of mercury (I).

In another aspect of the present variant embodiment, the reagent is capable of oxidation of the analyte, which includes an antioxidant. The reagent may include ferricyanide salt, dichromate salts, permanganate salts, the oxides of vanadium, dichlorophenolindophenol, complexes of osmium with bipyridine and quinones.

In another aspect of the present variant embodiment, the reagent is capable of recovery of an analyte, comprising the oxidant. The reagent may include iodine, triiodide salt, ferrocyanide salt, ferrocene, salt Cu(NH3)42+and salts of Co(NH3)63+.

In another aspect of the present variant embodiment, the touch, the camera additionally includes a buffer contained inside touch camera. The buffer is selected from the group consisting of phosphates, carbonates, salts of alkali metals medicinova acid and alkali metal salts of citric acid.

In another aspect of the present variant embodiment, the device additionally includes a heating element. The heating element may include an electrical resistive heating element or copies thermal substance, contained within touch camera, such as aluminum chloride, lithium chloride, lithium bromide, lithium iodide, lithium sulfate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate and mixtures thereof.

In another aspect of the present variant embodiment touch the camera includes support means contained within touch of the camera. The supporting means may include a mesh, a sheet of non-woven material, a fibrous filler, macroporous membrane, sintered powder, and combinations thereof. Either the reagent or buffer, or both, they can be inside a supporting means or to be deposited on a supporting tool.

In another aspect of the present variant embodiment of the second electrode is placed opposite to and at a distance of less than about 500 microns from the first electrode is less than about 150 microns from the first electrode, or less than about 150 microns, and greater than about 50 microns from the first electrode.

In another aspect of the present variant embodiment, the device additionally includes an interface for communication with the meter. The interface can transmit the voltage or current.

In another aspect of the present variant embodiment of the electrochemical cell includes a thin-layer electrochemical cell.

In the second variant embodiment before the book refers to a method of detecting the presence or absence of water sample redox reactive analyte, which includes ensuring the availability of devices for detecting the presence or absence of water sample analyte, the device includes an electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent contained within the touch of the camera, and the electrochemical cell constructed replaceable after use in a single experiment, and the compound is liable to undergo a redox reaction directly with the analyzed substance generating an electrical signal indicating the presence or absence of the analyte; ensuring the availability of water sample; allowing the sample to flow through the hole inside touch camera, so touch the camera being filled; and receiving (implementation) electrochemical measurements, indicating the presence or absence of the analyte present in the sample.

In one aspect of the present variant embodiment of the electrochemical measurement is an amperometric measurement, potentiometric measurement, coulometric measurement or quantitative measurement.

In another aspect, the present is about a variant embodiment of the method includes the additional step of heating the sample, where stage heating is preceded by a stage of obtaining electrochemical measurements. Alternatively, the method may include an additional stage of heating the sample, where the stage of heating is followed by the stage of obtaining an electrochemical measurement; and then obtaining a second electrochemical measurements, indicating the presence or absence of the second analyte present in the sample.

In another aspect of the present variant embodiment, the touch, the camera additionally includes a buffer, such as phosphate buffer, carbonate buffer, a salt of an alkali metal medicinova acid and alkali metal salt of citric acid.

In the third variant embodiment provides a method of measuring the sulfur dioxide in the sample of wine, where sulfur dioxide is free form and the bound form and the ability to undergo redox reaction with the reagent, and the redox reaction is the kinetics of the reaction, and the method includes the stage of ensuring the availability of a device comprising an electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent, the ability to undergo redox reaction with sulfur dioxide, where the electrochemical cell RMSE is strayaway replaced after use in a single experiment; premises sample wines in the electrochemical cell, thereby initiating the redox reaction; and obtaining (implementation) of the first electrochemical measurements indicating the level of sulfur dioxide in the free form.

In one aspect of the present variant embodiment, the method additionally includes the stage of heating the sample of the wine for a period of time sufficient to sulfur dioxide in the bound form was reacted with the reagent, where stage heating is carried out after the stage of receiving the first electrochemical measurement; and thereafter obtaining a second electrochemical measurements, indicating the overall level of sulfur dioxide in a free form and a bound form. Alternatively, the method may include an additional stage receiving the second electrochemical measurements, indicating that the kinetics of the reaction of sulfur dioxide in bound form with a reagent, where the second electrochemical measurement is obtained after the stage of receiving the first electrochemical measurement; and calculating the level of the bound sulfur dioxide using reaction kinetics.

In the fourth variant embodiment provides a method of manufacturing a device for detecting the presence or absence of redox reactive analyses what has been created substances in the water sample, moreover, the device includes an electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent contained within the touch of the camera, and the electrochemical cell constructed replaceable after use in a single experiment, and where the reagent is able to undergo redox reaction directly with the analyzed substance generating an electrical signal indicating the presence or absence of an analyte, the method includes forming openings extending through the sheet of material having a large electric resistance, the opening defines a side wall touch camera; attaching the first layer having the first electrode to the first side of the sheet and stretch over the hole, defining a first end wall touch camera, and the first electrode facing the first side of the sheet; attaching a second layer having a second electrode, the second side of the sheet and stretch over the hole, defining a second end wall touchscreen camera with substantial alignment with the first layer during application, the second electrode facing to the second side of the sheet, the sheet layers and four is irout strip; the formation of holes in the strip in order to make possible the introduction of the sample in the sensor chamber; and ensuring the availability of the reagent, the ability to undergo redox reaction directly with the analyzed substance, where the reagent is contained within touch of the camera.

In one aspect of the present variant embodiment, the method includes the additional step of ensuring the availability of the ventilation duct in the strip, to allow for venting of air displaced from the touch of the camera when touch the camera fills the sample. Another additional step includes attaching an electric resistive heating element to the strip.

In an additional aspect of the present variant embodiment, the hole has a rectangular cross-section.

In an additional aspect of the present variant embodiment, at least one electrode includes a noble metal such as palladium, platinum and silver. At least one of the electrodes may be a deposited coating layer of metal. The electrodes can be glued to the sheet, for example, using an adhesive, such as a thermally activated adhesive, pressure-sensitive adhesive, a thermally curable adhesive, chemically curing adhesive, hot melt adhesive or heat treatment of the key razmyagcheny glue.

In another aspect of the present variant embodiment, the method includes additional stages, such as ensuring the availability of exothermic substance or buffer contained within the sensory chamber; applying by printing the reagent or buffer on at least one of the walls touch the camera; or the availability of supporting tools, such as a mesh, a fibrous filler, macroporous membrane, sintered powder, and combinations thereof, contained within touch of the camera. The reagent may be deposited on a supporting tool or contained within it.

In another aspect of the present variant embodiment, at least the sheet or one of the layers of the device manufactured in accordance with the present method, is a polymeric material selected from the group consisting of a complex of the polyester, polystyrene, polycarbonate, polyolefin and mixtures thereof. Alternatively, at least the sheet or one of the layers is a polyethylene terephthalate.

In another aspect of the present variant embodiment of the second electrode is attached opposite to the first electrode at a distance of less than about 500 microns from the first electrode; less than about 150 microns from the first electrode; or less than about 150 microns, and greater than about 50 microns from the first electrode.

<> Brief description of drawings

Figure 1 depicts a top view of the electrochemical cell.

Figure 2 depicts a view in section along the line 2-2 in figure 1.

Figure 3 depicts the end view in section along the line 3-3 in figure 1.

Figure 4 schematically depicts heated electrochemical cell in cross section, taken along the longitudinal midline of the cell.

A detailed description of the preferred options incarnations

The following description and examples illustrate in detail the preferred embodiment of the present invention. Specialist in the art will recognize that there are numerous variations and modifications of the present invention, which covered his essence. In accordance with this description of the preferred variant of the embodiment should not be construed as limiting the essence of the present invention.

The sample and an analyte

In a preferred variant embodiment provides a method and apparatus for measuring the levels of oxidant or antioxidant in the sample fluid. The method and apparatus are applicable to any oxidant or antioxidant that exists in the liquid sample is measured in a representative concentration. Antioxidants that can be analyzed include, for example, sulfur dioxide and ascorbic acid. xianti, which can be analyzed include, for example, chlorine, bromine, iodine, peroxides, hypochlorite and ozone. Water-insoluble oxidants or antioxidants can also be analyzed, if may be prepared in aqueous form, for example, by the use of detergent for the preparation of emulsions of water-insoluble redox reactive analyte.

Methods and devices for obtaining electrochemical measurements of liquid samples are additionally discussed in the joint application for U.S. patent No. 09/616433, filed July 14, 2000 and entitled "IMMUNOSENSOR", joint application for U.S. patent No. 09/616512, filed July 14, 2000 and entitled "HEMOGLOBIN SENSOR, and a joint application for U.S. patent No. 09/616556, filed July 14, 2000 and entitled "ELECTROCHEMICAL METHOD FOR MEASURING CHEMICAL REACTION RATES", each of which is included here by reference in its entirety.

The device and method can be used with any sample containing an analyte, which is a liquid and which is capable of dissolving the redox reagent to a sufficient degree. Typical samples include drinks, such as fruit and vegetable juice, carbonated drinks, water, beer, wine and spirits. However, not alleged the Xia, that method is limited to samples of edible products. If the sample is not in liquid form or is not capable of dissolving the redox reagent sufficiently, then an analyte contained in the sample can be extracted in an appropriate liquid with use of methods of extraction are well known in the art. The sample can be pretreated prior to its introduction into the electrochemical cell. For example, the pH may be raised to the desired level by means of a buffer or neutralizing agent, or may be added a substance that does oxidants or antioxidants that interfere with the measurement, directionspanel. Before introduction into the cell sample may also be pre-heated in order to increase the rate at which flows through the redox reaction.

The electrochemical cell

The electrochemical cell of the preferred variants of the embodiments is replaceable and designed for use in a single experiment. In a preferred variant embodiment of the electrochemical layer is a thin-film sensor, such as described in U.S. patent No. 5942102 (included here by reference in its entirety). Preferred in the version of this embodiment the electrochemical cell is illustrated in Fig.1-3. The cell illustrated in figures 1 to 3, includes a polyester core 4 having a circular opening 8. Hole 8 defines a cylindrical side wall 12 of the cell. On one side of the core 4 on the attached sheet 1 of complex polyester having a sprayed coating of palladium 2. The sheet is adhered by the adhesive 3 to the core 4, while palladium 2 is placed adjacent to the core 4 and overlaps the hole 8. The second sheet 7 of complicated polyester having a second sprayed coating of palladium 6, is attached by means of contact adhesive 5 to the other side of the core 4 and overlaps the hole 8. Thus, the cell having a cylindrical side wall 12, closed at each end by metal palladium 2, 6. In the Assembly openings 9 in order to ensure the flow of solution in the cell or its introduction under the action of absorption or capillary forces and to allow the air to care. The metal film 2, 6 are connected to the corresponding electrical connectors or structures with which can be applied potentials and measured their changes over time.

Such thin-layer electrochemical cell receive first by forming holes extending through the sheet of material having a large electric resistance, and the hole defines with the Oh side wall of the electrochemical cell. Appropriate materials having a large electric resistance, which can be used for the manufacture of a sheet containing a hole, or to other layers of the cell include, for example, materials such as polyesters, polystyrenes, polycarbonates, polyolefins, polyethylene terephthalate, mixtures thereof and the like. In a preferred variant embodiment of the hole in the sheet is rectangular, but can also be used for other shapes, for example round.

After forming the holes of the first thin layer electrode then attach to one side of a sheet of material having a large electric resistance, stretching out on top of the hole (covering the hole) and forming the end wall. The layer may be glued to the sheet, for example, by glue. Appropriate adhesives include, for example, thermally activated adhesives, pressure sensitive adhesives, thermally-curable adhesives, chemically curing adhesives, hot melt adhesives, thermally razmagchenia adhesives and the like. The electrode layer is prepared by coating (e.g., via sputtering) of a sheet of material having a large electric resistance, an appropriate metal, such as palladium.

Then, a second thin layer of the electrode is attached on the opposite article is Rone material, having a large electric resistance, also extending over the holes (covering the hole)so that it forms the second end wall. In a preferred variant embodiment of layers of electrodes are attached opposite each other at a distance smaller than about 1 millimeter, preferably less than about 800 microns, more preferably less than about 600, or preferably less than about 500 microns, more preferably less than about 300-150 microns, even more preferably less than 150 microns and most preferably between 25, 40, 50, 100 and 150 microns. Then create the second hole or entrance, so that the liquid can flow into the cell. Such input can be created by forming a cut along one edge of the device that extends through layers of electrodes and the hole. Layers of electrodes provided with a connecting means, which provide the ability to place sensors in the measuring chain.

Chemicals for use in the cell, such as redox reagents, buffers, and other substances can be applied (supported) on the electrodes or walls of the cell, one or more independent supporting means contained within the cell, or can be self-sustaining. If chemicals must be applied to the elec the birth or walls of the cell, chemicals can be applied by using the methods of application are well known in the art, such as ink jet printing, screen printing, lithography, ultrasonic spraying, slot coating, gravure printing, and the like. Appropriate independent support means may include, but are not limited to, mesh, sheet, nonwoven, fibrous fillers, macroporous membrane and sintered powders. Chemicals for use in the cell can be applied to a supporting tool or contained in the support tool.

In a preferred variant embodiment, the materials used inside the cell, as well as the materials used to construct the cells are in a form suitable for mass production, and the cells are constructed so that they can be used in a single experiment, and then discarded.

In accordance with a preferred variant embodiment of the replaceable cell is a cell that is sufficiently inexpensive to manufacture, so that it can economically acceptable to use just one single test. Secondly, the cell can be conveniently used in only one single test. "Uncomfortable" in this context means that such Sha and, as washing and/or re-loading of reagents, must be taken for processing cells after a single use, to make it suitable for subsequent use.

"Affordable" in this context means that the final price of the test result for the user is the same or greater than the cost of buying and using cell, and the sales price of the cell is set by the cost of delivery of cells to the user plus the margin. For many applications this corresponds to the requirement that the cells had a relatively low cost materials and simple manufacturing processes. For example, the materials of the electrodes for the cells should be inexpensive, such as coal, or should be used in sufficiently small quantities so that could be used expensive materials. Screen printing using carbon or silver ink is a process suitable for forming electrodes using relatively inexpensive materials. However, if it is desirable to use such materials of the electrodes, as platinum, palladium, gold or iridium, the methods with the best use of materials, such as deposition by sputtering or deposition from the vapor or gas phase, are more suitable because they can give eliminate the nio thin film. Preferably, the materials of the substrates for the replaceable cells were also inexpensive. Examples of such inexpensive materials are polymers, such as polyvinyl chloride, polyimide, complex, polyester, and paper and paperboard coated.

The methods cells preferably are suitable for mass production. These methods include the production of multiple cells on the sheet and dividing the sheet into the individual strips after the main stages of Assembly, and the manufacture of cloth, where the cells are manufactured on a continuous canvas, which is subsequently divided into individual strips. Sheet processes are most suitable for use when making requires accurate spatial alignment of multiple parts and/or when to use hard materials substrates in cells. Plain processes are most suitable for use when combining items on the canvas is not as critical and therefore can be used flexible materials in the form of paintings.

The requirement for convenient single use for the replacement cell is desirable to ensure that users do not try to reuse the cell and may get an inaccurate test result. Requirement disposable IP is of use for the cell can be formulated in the instructions for users attached to the cell. More preferably, the cell can also be made so that the use of a cell more than once is difficult or impossible. This can be achieved, for example, by including in the composition of the reagents that are washed out or consumed during the first test and are therefore non-functional in the second test. Alternatively, the signal obtained during the test can be checked for the presence of indicators that the reagents in the cell has already reacted, such as abnormally high initial signal, then the test is aborted. Another method includes providing a means for breaking the electrical connections in the cell after completion of the first test in the cell.

Measurement of antioxidants, known from the literature, do not comply with these requirements substitutability. The cell described Richard J. Price et al., Analyst, November 1991, Vol.116, pages 1121-1123, uses silver wire, platinum wire and platinum disc as electrodes for the cell, measuring the antioxidants in the oil. Platinum wire are too expensive to use them in device for a single use according to the present application, and the cell is designed for continuous monitoring, not a single test. In U.S. patent No. 5518590 Fang describes the other cell for measurement of antioxidants in the oil. This cell also uses a platinum wire as an electrode and also is designed for continuous use, namely for the effective implementation of multiple tests over time. This cell also requires the presence of a layer of liquid or gel containing polar solvent. Such a device is unsuitable for mass production and storage because of the need to hold liquid components, possibly for long periods of time before use.

The electrodes

At least one of the electrodes in the cell represents the sensor electrode, defined as the electrode is sensitive to the number of recovered redox agent in the case of an antioxidant, or oxidized redox agent in the case of an oxidant. In the case of a potentiometric sensor, where the potential of the touch electrode is an indicator of the level of analyte present, there is a second electrode acting as a reference electrode, which acts, creating the potential comparison.

In the case of amperometric sensor, where the current touch electrode is indicative of the level of analyte in the sample is present at least one electrode, which function is ionium as a counter-electrode to close the electrical circuit. This second electrode may function as a reference electrode. Alternatively, a separate electrode can realize the function of the reference electrode.

Materials suitable for the touch electrode, counter-electrode and reference electrode are compatible with redox reagents present in the device. Compatible materials should not chemically interact with the redox reagent or any other substance present in the cell. Examples of appropriate materials include, but are not limited to, platinum, palladium, carbon, indium oxide, tin oxide, mixed oxide (a mixture of oxides) indium/tin, gold, silver, iridium and mixtures thereof. These materials can be formed in the structure of the electrodes using any suitable method, for example by sputtering, deposition from the vapor or gas phase, screen printing, thermal evaporation or lithography. In preferred embodiments embodiment the material is deposited or applied using a screen printing for forming electrode structures.

Non-limiting examples of materials suitable for use in the reference electrode including a metal/metal salt, such as silver in contact with silver chloride, bromide behold EBRA or silver iodide and mercury in contact with chloride mercury (I) or sulfate mercury (I). The metal may be deposited using any suitable method, and then brought into contact with the corresponding metal salt. Usable methods include, for example, the electrolysis in the solution of the corresponding salt or chemical oxidation. Such systems are a metal/metal salt provide better control of potential ways potentiometric measurements than the system only with metal components. In a preferred variant embodiment of the system of electrodes of the metal/metal salt used as a separate reference electrode in amperometric sensor.

The redox reagent

Suitable for use redox reagents include reagents that are able to undergo redox reaction with the analyzed substance of interest. Examples of such redox reagents suitable for use in the analysis of the analyzed substances-antioxidants include, but are not limited to, salts of ferricyanide, dichromate, complexes of osmium with bipyridine, oxides of vanadium and permanganate. Organic redox reagents, such as dichlorophenolindophenol and quinones, are also suitable for use. Pre is respectful variant embodiment of the redox reagent for analysis of antioxidant is a ferricyanide. Examples of reagents suitable for use in the analysis of the analyzed substances-oxidants include iodine and salt triiodide, ferrocyanide, ferrocene, Cu(NH3)42+and Co(NH3)63+. In a preferred variant embodiment of the redox reagent for measuring developer is a ferrocyanide.

Buffer

Optionally, the electrochemical cell may be a buffer together with the redox reagent in the dried form. If you use a buffer, it is present in such quantity that the resulting pH is suitable for the establishment of oxidizing (or reducing) potential redox reagent at a level suitable for use in the oxidation (or recovery) of the analyzed substances of interest, but not other particles that can detect undesirable. The buffer is present in a quantity sufficient to ensure that during the test to maintain the pH of the sample being at a given level. Examples of buffers suitable for use include phosphates, carbonates, salts of alkali metals medicinova acid and alkali metal salts of citric acid. The choice of the buffer will depend on the desired pH value. The buffer is selected in such the way, so it does not interact with the redox reagent. Alkaline buffers are preferred for use in combination with sodas.

Other substances that are present inside the cell

In addition to redox reagents and buffers and also other substances can be present inside a cell. Such substances include, for example, viscosity modifiers and polymers with low molecular weight. Inside a cell may also contain a hydrophilic substance, such as polyethylene glycol, polyacrylic acid, dextran, and surfactants, such as those sold by Rohm & Haas Company of Philadelphia, Pennsylvania under the trademark Triton™or ICI Americas Inc. of Wilmington, Delaware under the trademark Tween™. Such substances may increase the fill rate of the cell, to provide a more stable measurement and slow evaporation of samples of small volume.

The method of measuring the concentration of an analyte

When measuring an analyte - antioxidant or oxidant present in the sample, the sample is introduced into the sensor cell, and the sample dissolves the dried reagents present in the cell. Then the redox reagent interacts with any of the interest antioxidants or is xidants, present in the sample, with the formation of restored or the oxidized form of the redox reagent. In the case of a potentiometric sensor is obtained from the ratio of the oxidized and reduced forms of the redox reagent captures the potential of a touch electrode against the reference electrode. Then this potential is used as a measure of the initial concentration of the analyte in the sample.

In a preferred variant embodiment of the sensor cell works as an amperometric sensor. In accordance with this alternative embodiment of reduced (or oxidized) redox reagent formed by the interaction with the selected analyzed substances, electrochemically oxidized (or restored) on the touch electrode. The current generated as a result of this electrochemical reaction, is then used to measure the initial concentration of the analyzed substance in the sample. In other embodiments, embodiments of the sensor works in potentiometric or coulometric modes.

The cell electrodes are used to generate an electrical signal, i.e. a voltage or current that can be read the attached meter. In a preferred variant embodiment provides the W interface for connecting the cell to the meter. The meter can display the dimension in visual, audio or other form, or it may store the measurement in electronic form.

Heating of the sample

Some of analyte-oxidants or antioxidants slow interact with the redox reagent. To accelerate the reaction and, thus, reduce the time required to obtain the measurement results, the sample can be heated. In a preferred variant embodiment provides means for heating the sample in a replaceable electrochemical sensor device.

Two tools that are suitable for use in the heating of the cell described in WO 99/46585 (included here by reference in its entirety). WO 99/46585 describes the method of determining the concentration of an analyte in a sample, where the sample is heated, and the concentration of the analyte (or particles, representing an analyte) is measured at a given point on the curve response (defined as the dependence of one variable reactions from the other) by using tools that do not depend on temperature. The sample can be heated either by using exothermic reactions occurring at the contact of the sample with an appropriate reagent or reagents, or sample can be heated electrically by means of current supplied to the resistive elements, is knitted with a cell.

One way of sample heating by exothermic reaction includes placement in electrochemical reagent that releases heat upon contact with the sample. Examples of such reagents include salts that produce heat when they are dissolved, such as aluminum chloride, halide salts of lithium, lithium sulfate, halide salts of magnesium and magnesium sulfate. The reagent or reagents used for heat release, not have a negative effect on the functioning of the other active elements in the cell, for example, by corrosion of the materials of the electrodes, the interaction with the analyzed substance in such a way that it affects his response, or by harmful interactions with others present reagents.

When a sample needs to be heated electrically, the electrochemical cell can be provided with an electrical resistive element. Figure 4 depicts the preferred embodiment of the electrochemical sensor described in WO 99/46585. The sensor includes a non-conductive substrate 21, carrying the first electrode 22, the separator layer 23, having done it a round hole 30, which defines the circular wall 30 of the cell. The first electrode 22 determines one of the ends of the cell, while the second end is defined by the second layer 24 of the electrode, which is located on the second C is bodasen layer 25. The layer 26 of metal foil provides electrical contact with the resistive bridge 29 formed in the second non-conductive layer 25. The insulating layer 27 provides insulation that prevents heat loss from the layer 26 of metal foil. A hole 28 is formed in the insulating layer 27 to allow access for electrical connection to the foil 26.

In preferred embodiments, embodiments of the resistive elements can be prepared by soaking one or more non-conductive layers, which is a layer of an electrode using such substances as carbon particles. Non-conductive layers may include materials such as plastic or rubber. Layer impregnated with rubber or plastic forms a resistive bridge between the electrode of the electrochemical cell and the layer of metal foil. When the resistive element is applied potential, the impregnated layer of rubber or plastic generates heat, which, in turn, heats the sample in the electrochemical cell. Alternatively, at least two tracks with low resistance, connected by a path with high resistance can be formed on the outer surface of the sensor. In this variant embodiment paths with low resistance can be used to create contact with the meter, and track high the m resistance generates an electrical resistive element.

Devices with multiple cells

In some situations, it may be desirable measurement in the sample more than one analyte-oxidant or antioxidant. This can be achieved by using a series of two or more electrochemical cells described above. Each cell contains a redox reagent suitable for use with one of the analyzed substances present in the sample. Each cell is equipped with buffers or the heating means, if required for that particular analyte. This number of cells can be used not only to determine the known concentration of the analyzed substance of interest, but they can also be used for screening (study of the composition) of a sample with an unknown composition of the analyzed substances on the presence or absence of many of the analyzed substances.

Assumed various ways to implement a variety of cells. In one variation of the embodiments of the methods of forming cells, described above, used for the manufacture of devices with many sensory cells and electrodes, but having one or more layers of insulating material. In another variant embodiment, the two or more electrochemical cells, described above, are glued to the location or directly with each other, or stick to a single material substrate. Alternatively, two or more cells, described above, but containing different reagents may be packaged together in a set, suitable for use in a particular application, i.e. in the analysis of a sample containing many of the analyzed substances or different forms of the same analyte.

Analysis of sulfur dioxide in wine

One example of analysis is useful where the heating of the sample is a measurement of sulfur dioxide in wine. Sulfur dioxide in wine acts as an antioxidant and, as a rule, present in two forms: a free form and a bound form. Freeform faster oxidized redox reagent in the sensor, than the bound form. Usually it is desirable to measure both free and bound forms of sulphur dioxide in wine. For measurement of both forms in the electrochemical cell includes a heating means. Sample the wine is placed in the sensor cavity, at this present redox reagent rapidly interacts with the free sulfur dioxide generating the touch signal. This signal is analyzed, and then the sample is supplied with heat by means of a heating means. In a preferred variant embodiment of the heat is supplied to Zelenogo growth temperature, however, to avoid excessive evaporation of the sample. After the passage of an appropriate period of time when the temperature is high, the associated sulfur dioxide interacts with the redox reagent, thereby generating the second touch signal. From these two signals to obtain the concentration of free sulfur dioxide in the sample and its total concentration, and further the difference get the concentration of free and bound forms. Although this two-stage method is best to obtain the concentration of free and bound forms of sulfur dioxide in wine, is assumed to be also other uses for this method. For example, two (or more) stage method can be used for analysis of relevant samples containing an analyte in two or more forms with different kinetics of the reaction, or samples containing two or more analyte, each of which has different kinetics of the reaction.

Obtaining electrochemical measurements using the sensor to the antioxidant or the antioxidants

In certain embodiments of the embodiment of the information related to the speed of a chemical reaction, which generates at least one electrochemically active product can be obtained using the sensor in the case to ensure that the chemical reaction is localized in space, remote from the electrode used for electrochemical interaction between the electrochemically active product (s).

The area of a chemical reaction is quite remote from the electrode, so that the mass transfer electrochemically active substances from chemical reactions to the electrode effectively controls the current flowing to the electrode at any time. This arrangement provides a substantially linear change (gradient) of the concentration of the electrochemically active substance between the chemical reaction and the electrode. The concentration of the electrochemically active material on the electrode is supported on the average equal to zero due to the electrochemical reaction occurring there. Therefore, the change with time of the magnitude of the concentration gradient will essentially be determined by the time dependence of the concentration of electrochemically active substances in the field of chemical reaction and the ratio (odds) diffusion of electrochemically active product (s) reaction in a liquid medium. Since the current flowing at the electrode is proportional to the gradient of concentration of the electrochemically active material on the electrode, the dependence of this current on time will reflect the time dependence of the chemical reaction taking place in a remote oblstat provides the ability to use current measured on the electrode (or the last charge, if the current is integrated), as a convenient measure of the rate and degree of completion of chemical reactions taking place.

An example of a suitable way to ensure that the chemical reaction is removed from the working electrode, represents immobilization (fixation) of one or more components of the reaction on a solid surface, remote from the electrode. Component (s) of the reaction can be immobilized by their inclusion in the polymer matrix, which is dried or otherwise attached to a solid surface. Component (s) of the reaction can also be linked directly from a solid surface by either chemical or physical connection. Alternatively, one or more of the components of the reaction can simply be dried on a solid surface without special means of immobilization. In this situation, one or more of the components of the reaction have, essentially, a low mobility in the liquid matrix, the filling of the electrochemical cell so that they essentially do not migrate from where they are dried for a period of time, when the electrochemical current can be monitored to make the necessary measurements. In this context, the relatively slow migration means, tocomponent, moving slower and all required for the chemical reaction, coming so close to the working electrode, which is the time dependency of the current flowing in the electrode begins to influence the kinetics of depletion type Cotrell.

The range of distances that divide the area of the chemical reaction and the working electrode in the preferred embodiments embodiments, preferably is less than about 1 cm, preferably less than 5 mm, more preferably is in the range between 5, 10, 50, 100, 200, 500 microns and 5 mm, more preferably between 5, 10, 50, 100, 200 and 500 microns, and most preferably between 5, 10, 50, 100 and 200 microns.

In addition to the working electrode provides at least and a counter-electrode in contact with the sample fluid circuit of the electrochemical circuit. If necessary, the counter-electrode can function as a combined counter-electrode/reference electrode or may be a separate reference electrode. In a preferred variant embodiment of the working electrode and the counter-electrode, preferably separated by a distance greater than about 300 microns, preferably by a distance greater than about 500 microns, more preferably by a distance of between about 500 microns and 10 mm, even more preferably the distance is eaten between about 500 microns and 1, 2, 5 mm and most preferably between 1 and 2, 5, 10 mm.

The working electrode is constructed from materials that do not interact chemically with any component with which it will come into contact during use, to such an extent as to distort the response of the electrode in the form of current. If the working electrode should be used as the anode, examples of usable materials are platinum, palladium, carbon, carbon in combination with an inert binder, iridium, indium oxide, tin oxide, a mixture of indium and tin oxides. If the working electrode should be used as the cathode, then in addition to the materials listed above, other suitable materials are steel, stainless steel, copper, Nickel, silver and chrome.

Examples of materials suitable for use as counter-electrode, consists of platinum, palladium, carbon, carbon in combination with an inert binder, indium, indium oxide, tin oxide, a mixture of indium and tin oxides, steel, stainless steel, copper, Nickel, chromium, silver and silver, covered essentially insoluble salt of silver, such as silver chloride, silver bromide, silver iodide, ferrocyanide silver ferricyanide silver.

The area of the chemical reaction may be localized on a smooth wall or on p is tiolette, remote from the working electrode. The area of the chemical reaction may be on the same plane as the working electrode, or, more preferably, in a plane essentially parallel to the working electrode opposite him.

The sensor is suitable for use in certain embodiments of embodiments, includes a working electrode and a counter-electrode, which is placed on an electrically insulating substrate. The second substrate is a layer of chemical reagents, where at least one of the reagents is essentially immobilized (fixed) on the substrate. When using the space between the walls of the sensor is filled with a liquid containing a substance which is capable of interaction with reagents, obtaining at least one electrochemically active substances. The product of a chemical reaction diffuses to the working electrode, where the electrochemically active material electrochemically interacts with the current. The amount of current or charge held in or for a certain time, or the time dependence of the current or previous charge can then be used to obtain a measure of the speed or degree of completion of chemical reactions occurring in the reagent layer.

In another variant embodiment of the sensor reagents are the and the counter-electrode, located on a substrate having a large electric resistance. In this variant embodiment, the materials of construction of the counter-electrode are inert to interaction with any of the components of the reagents placed on the electrode.

The method of obtaining electrochemical measurements described above can be applied to any usable electrochemical system comprising the system of antioxidants and oxidants. An example of the application of this method to a typical, though not-antioxidant electrochemical system is a measurement of glucose in whole blood using an enzyme PQQ (from the English. Pyrroloquinoline quinone-pyrroloquinoline quinone)-dependent glucosegalactose (GDHpqq) and mediator oxidation-reduction. In this reaction the glucose in the blood interacts with GDHpqq with the formation of gluconic acid. In this PQQ process the enzyme is recovered. Then the mediator, such as potassium ferricyanide, oxidizes PQQ in the enzyme and forms a ferrocyanide. The enzyme in the oxidized form can then interact with the remaining glucose. The net effect of this reaction is the generation of two molecules of ferrocyanide on each reacted molecule of glucose. Ferrocyanide is an electrochemically active substance and can therefore b is to be oxidized on the electrode current. Other suitable enzymes for this reaction are glucose oxidase (GOD) or NAD (from the English. Nicotineamid)-dependent glucosegalactose. For other reactions can be used lactate dehydrogenase and alcoholdehydrogenase. Other usable mediators oxidation-reduction include ferrocene, complexes of osmium with bipyridine and benzophenone.

Interaction of glucose in whole blood with the enzyme can be slow, taking up to several minutes to complete. In addition, the higher the hematocrit in a blood sample, the slower the reaction. The hematocrit of the blood represents the volume fraction of erythrocytes in a sample of whole blood. For example, a solution containing 50 mg/ml GDHpqq, 0,9 M potassium ferricyanide and 50 mm buffer at pH=6,5, was applied to the counter-electrode, and then removed the water, leaving the dried reagent layer. In this layer GDHpqq is large enough and so now immobilized on the counter-electrode, while the ferricyanide can be mixed more uniformly in the liquid in the electrochemical cell. A blood sample was injected into the cell and a potential of +300 mV was applied directly between the working electrode and counter-electrode. Although the potential of +300 mV is the most preferred for the oxidation of ferrocyanide, potential, preferably, is in the range between +0 and +600 mV, preferably between +50 and +500 mV, and more preferably between +200 and +400 mV. In the cell, the working electrode consisted of a layer of gold deposited on a substrate of complex polyester, and a counter-electrode consisted of a layer of palladium deposited on a substrate of complex polyester.

Current graphs recorded for blood samples with different hematocrit values showed a higher reaction rate at lower hematocrit blood, that is, 20, 42, and 65% hematocrit in the blood. The level of glucose in each blood sample was approximately the same, namely 5.4 mm for the sample with a hematocrit of 65%, 5.5 mm for the sample with a hematocrit of 42% and 6.0 mm for the sample with a hematocrit of 20%.

The measured current can be approximately described by the equation

i=-FADC/L,

where i is the current, F is a Faraday constant (96486,7 Coulomb/mol); A is the area of the electrode; D is the diffusion coefficient of ferrocyanide in the sample; C is the concentration of ferrocyanide in the field of reaction; and L represents a distance between the reaction region and the electrode.

The reaction rate, which is determined by the rate of change of C with time, therefore, is written as

dC/dt=-(L/FAD)di/dt.

For the reactions discussed above, between 6 and 8 seconds for samples with a hematocrit of 20, 42, and 65% of the average value is s di/dt was 3,82, 2.14 and 1,32 microamps/second, respectively. The diffusion coefficients of ferrocyanide for these samples was 2.0×10-6, 1,7×10-6and 1.4×10-6cm2/s for samples with hematocrit 20, 42 and 65%, respectively. The area of the electrode was 0,1238 cm2and L was 125 microns. These values give the reaction rate of 2.0 and 1.3 and 0.99 mm/s for samples with hematocrit 20, 42 and 65%, respectively.

The method described above, to measure the response of blood glucose may be appropriately modified to apply to other electrochemical systems, including systems oxidants or antioxidants, such as sulfur dioxide in wine, as it will notice a specialist in this field of technology.

The above description describes several methods and materials of the present invention. The present invention is susceptible to modifications to the methods and materials, as well as to changes in methods and devices. Such modifications become apparent to a person skilled in the art from consideration of the present description or application of the invention described herein. Therefore, it is not intended that the present invention is limited to a particular variant embodiment described here, but assume that it covers all modifications and alternatives, academies within the true scope and spirit of the present invention, disclosed in the accompanying claims.

1. Device for the detection of redox reactive analyte in an aqueous sample, and the device comprises an electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent contained within the touch of the camera, and the electrochemical cell constructed replaceable after use in a single experiment, and when this reagent is able to undergo redox reaction directly with the analyzed substance generating an electric signal.

2. The device according to claim 1, where the first electrode includes a touch electrode.

3. The device according to claim 1, where the first electrode contains a material selected from the group consisting of platinum, palladium, carbon, indium oxide, tin oxide, gold, iridium, copper, steel, and mixtures thereof.

4. The device according to claim 1, where the first electrode contains silver.

5. The device according to claim 1, where the first electrode is formed using a technique selected from the group consisting of sputtering, deposition from the vapor or gas phase, screen printing, thermal evaporation, inkjet printing, ultrasonic spraying, slot coating, gravure and lithography.

6. The device according to claim 1, where the second electrode includes a counter-electrode.

7. The device according to claim 1, where the second electrode contains a metal in contact with the metal salt.

8. The device according to claim 7, where the metal is in contact with a salt of metal selected from the group consisting of silver in contact with silver chloride, silver in contact with silver bromide, silver in contact with silver iodide, mercury in contact with mercury chloride (I), and mercury in contact with sulphate of mercury (I).

9. The device according to claim 6, where the electrochemical cell additionally includes a third electrode.

10. The device according to claim 9, where the third electrode comprises a reference electrode.

11. The device according to claim 1, where the reagent is capable of oxidation of the analyte-containing antioxidant.

12. The device according to claim 11, where the reagent is selected from the group consisting of ferricyanide salts, dichromate salts, permanganate salts, oxides of vanadium, dichlorophenolindophenol, complexes of osmium with bipyridine and quinones.

13. The device according to claim 1, where the reagent is capable of recovery of the analyte containing oxidant.

14. The device according to item 13, where the reagent is selected from the group consisting of iodine, triiodide salts, ferrocyanide salt, ferrocene, salts Cu(NH3)42+and salts of Co(NH3)63+.

15. The device according to claim 1, the de touch the camera further comprises a buffer, moreover, the buffer contained within the touch of the camera.

16. The device of clause 15, where the buffer is selected from the group consisting of phosphates, carbonates, salts of alkali metals medicinova acid and alkali metal salts of citric acid.

17. The device according to claim 1, additionally containing a heating element.

18. The device 17, where the heating element is an electrical resistive heating element.

19. The device 17, where the heating element is an exothermic substance contained inside touch camera.

20. The device according to claim 19, where the exothermic substance selected from the group consisting of aluminium chloride, lithium chloride, lithium bromide, lithium iodide, lithium sulfate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate and mixtures thereof.

21. The device according to claim 1, where the second electrode installed opposite to and at a distance of less than about 500 microns from the first electrode.

22. The device according to claim 1, where the second electrode installed opposite to and at a distance of less than about 150 microns from the first electrode.

23. The device according to claim 1, where the second electrode installed opposite to and at a distance of less than about 150 microns, and greater than about 50 microns from the first electrode.

24. The device according to claim 1, additionally containing an interface for communication with measure the LEM.

25. The device according to paragraph 24, where the interface transmits the voltage or current.

26. The device according to claim 1, where the electrochemical cell contains a thin-layer electrochemical cell.

27. The method of detecting the level of redox reactive analyte in an aqueous sample, and the method comprises a stage on which:

to ensure that a device containing electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent contained within the touch of the camera, and the electrochemical cell constructed replaceable after use in a single experiment, and the compound is liable to undergo a redox reaction directly with the analyzed substance generating an electrical signal;

ensure the availability of water sample;

allow sample to flow through the hole inside touch camera so that essentially fill touch the camera, and

get the electrochemical measurement indicating the level of analyte present in the sample.

28. The method according to item 27, further containing a stage of heating the sample, and stage of heating is preceded by a stage in the teachings of the electrochemical measurements.

29. The method according to item 27, further containing the stage at which heat the sample, and stage heating comes after the stage of obtaining electrochemical measurements, and then get a second electrochemical measurement that indicates the level of the second analyte present in the sample.

30. Method for measuring sulfur dioxide in the sample of wine, where sulfur dioxide is free form and the bound form and the ability to undergo redox reaction with the reagent, and the redox reaction is the kinetics of the reaction, and the method comprises a stage on which:

to ensure that a device containing electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent, the ability to undergo redox reaction with sulfur dioxide, where the electrochemical cell is constructed replaceable after use in a single experiment;

put a sample of wine in the electrochemical cell, thereby initiating the redox reaction, and

get the first electrochemical measurement indicating the level of sulfur dioxide in the free form.

31. The method according to item 30, optionally containing stage, on to the verge heated sample wines within a period of time, sufficient for reaction of sulfur dioxide in bound form with the reagent, and stage heating is carried out after the stage of receiving the first electrochemical measurements, and then get a second electrochemical measurement, indicating the overall level of sulfur dioxide in a free form and a bound form.

32. The method according to item 30, optionally containing a stage, on which:

get a second electrochemical measurement, indicating that the kinetics of the reaction of sulfur dioxide in bound form with a reagent, where the second electrochemical measurement of the gain stage after the receipt of the first electrochemical measurements, and

calculate the level of the bound sulfur dioxide using reaction kinetics.

33. A method of manufacturing a device for detecting the redox reactive analyte in an aqueous sample, and the device comprises an electrochemical cell having a sensor chamber, the first electrode, the second electrode, an aperture for introduction of the sample in the sensor chamber and the reagent contained within the touch of the camera, and the electrochemical cell constructed replaceable after use in a single experiment, and the compound is liable to undergo a redox reaction directly with Ana is isiramen substance generating an electrical signal moreover, the method comprises a stage on which:

forming a hole extending through the sheet of material having a large electric resistance, and the hole defines the side wall touch camera;

attach the first layer having the first electrode to the first side of the sheet and extend over the apertures defining a first end wall touch the camera, and the first electrode facing the first side of the sheet;

attach the second layer with the second electrode, the second side of the sheet and extend over the apertures defining a second end wall touchscreen camera with substantial alignment with the first layer during application, and the second electrode facing to the second side of the sheet, the sheet and layers form a strip;

form a hole in the strip in order to make possible the introduction of a sample to touch the camera, and

ensure the presence of a reagent that can undergo redox reaction directly with the analyzed substance, where the reagent is contained within touch of the camera.



 

Same patents:

FIELD: measuring engineering.

SUBSTANCE: method comprises applying two poles of the magnet core of a detector of vortex currents to the wall of the blade parallel to the baffles mounted behind the wall whose thickness should be measured. The poles of the pickup are provided with coils connected in series. The detector moves over the wall perpendicular to the baffles. The thickness of the wall is determined from the signal from the detector according to the preliminary calibration.

EFFECT: enhanced precision.

4 cl, 6 dwg

FIELD: medicine.

SUBSTANCE: method involves introducing physiologic sample into measuring instrument having electrochemical cell with working electrode and comparison electrode. The first electric potential is applied to the cell and the current flowing through the cell is measured during the first time period for determining the first time-current transition characteristic. Then, the second electric potential is applied to the cell for determining the second time-current transition characteristic. Then, preliminary concentration of the substances under study is calculated from the first and/or the second time-current transition characteristics. The preliminary concentration value with background value being subtracted is multiplied by correction coefficient for determining concentration of substance under study in the sample.

EFFECT: minimized analytical error caused by hematocrit number.

9 cl, 1 dwg

FIELD: electrical article manufacture.

SUBSTANCE: the invention is related to the quality control of the insulation of electrical articles during their manufacture, mainly when drying the articles with the hard insulation, based on the thermoreactive impregnating lacquers and compounds. The method essence consists in measuring the capacitance of the same insulation gap at two different frequencies. The frequency of 50-100 Hz is used a the low frequency, and the frequency of 10-100 kHz - as the high one. Then the humidity coefficient is determined as the ratio of the capacitance, measured at low frequency, the capacitance, measured (at high frequency. The humidity coefficient should be in the limits of 1.00-1.05.

EFFECT: increased accuracy and objectivity of the quality control.

FIELD: test equipment.

SUBSTANCE: method can be used for making method of inspection of thermo-emission condition of surface-ionization ion thermo-emitter easier. It allows conducting inspection of effectiveness, uniformity and selectivity of ionization of organic compounds on the surface of thermo-emitter during common measurement cycle without usage of test samples of organic compounds. Atmospheric pressure air is pumped close to surface of thermo-emitter at volumetric speed of (2-10) l/min. Humidity of air is put under control. Constant voltage of (30-600) V is applied between thermo-emitter and ion collector. Thermo-emitter is subject to heating at constant speed of heating. Thermo-emitter ion current temperature dependence is registered. Values are determined which characterize peaks of ion current at preset temperature dependence (position of peaks, current intensity, width of peaks, and speed of raise of peak currents). Thermo-emission condition of thermo-emitter is judged from values of received characteristics.

EFFECT: simplified procedure of inspection; elimination of test samples.

7 cl, 5 dwg

FIELD: investigating or analyzing materials.

SUBSTANCE: method comprises interrupting current that flows between the working and auxiliary electrodes of the electrochemical cell mounted in the fluid to be analyzed and measuring current potential of the working electrode with respect to the reference electrode at a given moment of time. The reference electrode is made of auxiliary electrode whose rate of discharge of the double electric layer differs from that of the working electrode. The measurements of the current potential is carried out after a lapse of time no less that the double time interval of the relaxation process after the current interruption, but less than the time period of the discharge of the double electric layer of the working and auxiliary electrodes.

EFFECT: expanded functional capabilities.

1 dwg

FIELD: medicine; chemical engineering.

SUBSTANCE: method involves adding 5 mole/l tartaric acid solution of pH=3.0 to bisubstituted 0.01 mole/l ammonium hydrophosphate solution. The solution is deaerated with oxygen concentration being less than 0.001% during 30 s at (-1.5) V. Electrolysis is carried out during 330 s at (-1.5) V. Gas supply is stopped and current-voltage curve is recorded at voltage scanning rate of 300 mV/s. Standard angiotensin II solution is added, stirred and electrochemical concentrating on is carried out on glass-graphite electrode during 330 s at (-1.5) V. Gas supply is stopped and current-voltage curve is recorded at voltage scanning rate of 300 mV/s. Analytical signal of angiotensin II concentration in potential range of 0.3-0.5 V relative to chlorine-silver electrode.

EFFECT: improved sensitivity and express-analysis features.

4 tbl

Membrane solion // 2260796

FIELD: electro-chemical analyzers for liquid and gaseous media.

SUBSTANCE: membrane solion can be used as for dense and micro-pore membrane. Device has case filled with internal solution, indicator electrode, separating membrane and tool for fixing membrane. Elastic member provided with holes is installed between separating membrane and tool for fixing membrane. Internal surface of elastic member follows external surface of indicator electrode. Diameters of holes in elastic member 200 times max exceed thickness of separating membrane. Holes in elastic member can have random shape. Sizes of holes along their minimal axes do not have to exceed thickness of separating membrane 200 times max.

EFFECT: improved reliability of operation within wider temperature range.

2 cl, 1 dwg

FIELD: identification of metal scrap from which metal or metal alloy is produced.

SUBSTANCE: method comprises steps of sorting metal scrap by groups according to their content; weighing each group; determining percentage content of elements in groups of metal scrap; determining percentage content of elements in the whole quantity of metal scrap; processing metal scrap; after processing, identifying produced metal alloy or metal and metal scrap by determining percentage content of each element in processed products; comparing results with data of percentage content for the whole quantity of metal scrap. Results are compared according to element or elements contained in metal or in metal alloy and characterized by less loss at processing. Metal scrap may be sorted to groups on base of preliminary analysis. At comparing results, losses for processing are taken into account.

EFFECT: enhanced process of identification of metal scrap from which metal or metal alloy is produced.

3 cl

Gas analyzer // 2260181

FIELD: inspection of hazardous matters content.

SUBSTANCE: gas analyzer can be used for inspecting presence of ammonia. Gas analyzer has measurement component content detector made in form of electro-chemical sensor provided with electrolyte consumed ding exploitation and device for detector signal processing and controlling which has in turn microcontroller with central processing unit and program memory unit. Memory element is fastened to case of detector which element is connected with central processing unit of microcontroller through interface. Processor unit provides integration of detector signal value and periodical recording of integral signal value to detector memory unit as well as reading of this value out of memory unit. Limit value of integral signal of the detector is introduced into program memory unit of microcontroller which value corresponds to service life of the detector. This value is periodically compared with current value of integral signal. Analyzer is provided with signaling unit which operates at the moment if current value of integral signal gets equal to limit value of integral signal of the detector.

EFFECT: higher quality inspection of value of integral signal.

2 dwg

FIELD: measuring technologies.

SUBSTANCE: method includes ionizing controlled gas by β or α particles with periodical collection of ionization charges from gas volume. Using charge-sensitive amplifier, only charge of gathered electrons is registered from each α and β particle, or in even time intervals, of adjustable length. To abolish ambiguousness of measurements in noble gases, ultra-pure molecular gas is added to them, effectively thermalizing electrons, drifting in gas under effect from electric collecting field.

EFFECT: broader functional capabilities, higher precision.

2 cl, 3 dwg

FIELD: thermal and nuclear power stations; meter calibration in extremely pure water of condensate type and power unit feedwater.

SUBSTANCE: for pH-meter calibration ammonia whose concentration varies by 1.5 - 2 times is dosed in working medium. Electric conductivity and temperature of working-medium H-cationized sample are measured. Measurement results are processed in computer with aid of set of equations characterizing ionic equilibrium in source sample and H-cationized samples. Calculated pH value is compared with measurement results.

EFFECT: enhanced precision and reliability of meter calibration in extremely pure waters.

1 cl, 1 dwg, 1 tbl

FIELD: mechanical engineering.

SUBSTANCE: device has housing provided with three cylinders made of a dielectric material. The housing receives the cylinder with a piston.

EFFECT: improved design.

5 dwg

FIELD: agriculture and soil science; evaluating water-physics properties of soils.

SUBSTANCE: porous probe communicating with water-filled tank is driven into soil, cathode is inserted in probe and anode, in soil. Voltage is applied to electrodes from dc power supply and soil moisture potential preventing water transfer from tank to soil is determined by measuring current between them.

EFFECT: reduced single measurement time due to eliminating escape of significant amount of water from measuring instrument.

1 cl, 1 ex

FIELD: servicing steel underground pipe lines; diagnosis of corrosion on pipe lines.

SUBSTANCE: pipe line under test is divided into sections and pit is made at boundaries; then electrical resistance is measured in section and at edge zones of these sections (in pits) by four-electrode scheme. Measured at edge zones are also thickness of pipe wall and its outer diameter. Specific resistance of pipe metal is calculated by these measurements. Electrical resistance of sections is calculated on basis of specific resistance and measured and specified magnitude are compared. Deviation of measured magnitude from specified ones is indicative of corrosion damage on these sections. Current and potential electrodes are located at distance no less than two diameters of pipe for enhancing measurement accuracy.

EFFECT: enhanced accuracy of measurement.

2 cl

FIELD: measuring engineering.

SUBSTANCE: method includes compensating variations of voltage sink-source of indicating ion-selective field-effect transistor caused by the deviation of potential of ion-selective diaphragm, measuring temperature of auxiliary electrode, and determining the ion activity from the mathematical model of the physicochemical processes inside the measuring cell. The device has auxiliary electrode and indicating ion-selective field-effect transistor temperature sensor of ion-selective diaphragm, which are submerged into the solution to be investigated, two operation amplifiers, resistor, three current sources, voltage source, commutator, second amplifier, analog-digital converter, control unit, indicator, and additional temperature sensor of the auxiliary electrode.

EFFECT: enhanced accuracy of measuring.

6 cl, 1 tbl

FIELD: biology, experimental medicine.

SUBSTANCE: the method deals with filling hermetically sealed, optically transparent by height active capacity of a chamber with suspension of abiotic microobjects prepared upon distilled or bidistilled water and supplying opposite-charge tension of the same power onto two plane-parallel electrodes followed by registering the amplitude of fluctuation in vision field of light microscope's ocular.

EFFECT: higher efficiency of measurement.

1 ex, 1 tbl

FIELD: methods for flaw detection of pipe-lines, applicable for inspection of pipe-lines in sections predisposed to corrosion cracking under voltage.

SUBSTANCE: after removal of the insulating coating from the pipe surface and before shooting of stress-corrosion defects of the sections of their surface with visible deposits of corrosion products containing siderite are determined loose corrosion products are removed from these sections. Shooting of stress-corrosion defects is carried out by an edgy-current, or magnetic-field, or magnetic eddy-current flaw detector by detection and separation of zones, in which the values of readings of the used flaw detector exceed the mean values of the given flaw detector in the defectless section of the pipe by more than 2.2 times. The point with the maximum value of readings of the used flaw detector is determined for each separate zone, and the section including this point is scraped bright to metal. The depth of the stress-corrosion defect is determined by a repeated registration of the maximum value of readings of the used flaw detector. The values of readings of the used flaw detector noted before scraping are determined in the points of appearance of stress-corrosion cracks, the lesser of them is selected, which is used as a criterion value for restriction of the zone of the pipe surface, the values of readings of the used flaw detector inside which exceed the found criterion value. The length and width of the stress-corrosion defect are determined by projecting of the restricted zone of the pipe surface onto the longitudinal and circular generating lines of the pipe with a subsequent measurement of the dimensions of the obtained projections.

EFFECT: reduced area of the inspected surface of the pipe-lines and scraped defective sections.

4 dwg

FIELD: non-destructive control.

SUBSTANCE: device has plate with aperture and bushing in it of same material. Engagement between plate and bushing forms a surface defect. Aperture in plate may be through or dead-end. Aperture in bushing may be made at angle or in parallel to sample surface.

EFFECT: broader functional capabilities.

3 cl, 4 dwg

FIELD: non-destructive control technologies.

SUBSTANCE: object is magnetized and relief of magnetic dispersion field by rotation of object table base with object placed on it, between poles of U-shaped magnet, scanning of magnetic field relief is performed by rotation of object table base with samples on it, between poles of magnetization means and two string sets of magnetic-sensitive elements. Conversion of magnetic dispersion field to electric signal is performed and information is read by compensation method due to fact, that axes of sensitivity of magnetic-sensitive elements of upper set and lower set are directed oppositely to each other. Device has magnetization means, magnetic-sensitive converter, reading means, information processing means and defects visualization means, object table with base. Examined object is placed on table base. Table base is mounted with possible rotation between poles of magnetization means and two identical parallel-placed string sets of magnetic-sensitive elements. Each sensitive element of upper set matches sensitive element of lower set, and sensitivity axes thereof are directed oppositely to each other.

EFFECT: higher trustworthiness and reliability of defects identification.

2 cl, 3 dwg

FIELD: measuring engineering.

SUBSTANCE: device has long line whose end is connected with a sensor which is in a contact with the mixture. The sensor is connected to the circuit of generator which is connected with frequency meter. The sensor is made of a capacitor which is connected to the line through the main inductive coils and to the generator through the two additional coils. The line can be made of coaxial line or shielded two-wire line provided with the capacitive sensor made of cylindrical capacitor or shielded flat capacitor, respectively. The surface of at least one of the wires of the sensor which is in a contact with the mixture can be covered with a dielectric shell.

EFFECT: enhanced accuracy of measuring.

3 cl, 4 dwg

Up!