Abstract: The present invention relates to a sensor for detection of oxides of nitrogen forming part of a gas, including a substrate consisting of a solid electrolyte on which a conductive pattern is arranged which includes at least two parts forming an anode and a cathode, a current being produced in the sensor in the presence of oxides of nitrogen and the anode and the cathode being connected to an external voltage source which is adapted to drive the current and to means for measuring the current, which constitutes a measure of the concentration of oxides of nitrogen in the gas. The sensor is adapted to generate the current by means of a transport of oxygen ions in the sensor which essentially originates from oxides of nitrogen being part of the gas, independently from the content of oxygen in the gas.

Abstract: A cell block for housing a sensor cell within a gas analyzer is mounted on the front panel of the analyzer, holding the sensor within a horizontal plane. The cell block is made of inexpensive and non-permeable material such as aluminum which is brazed and anodized. Entry and exit of sample gas is unique as is sample gas exposure to the sensor. Dead space is minimized and response time is improved. An insulated thermister in the cell block maintains accuracy over a wide range of temperatures. The device is RFI and EMI protected.

Abstract: Method and device for determining the concentration of one or more gases, e.g. O.sub.2 or CO.sub.2 or an anaesthetic gas, in a fluid e.g. a body fluid or a gas mixture. A membrane (12) permeable to the gases retains a solvent (22) e.g. dimethylsulphoxide. In contact with the solvent is a working electrode (24) of a surface area preferably less than 10 .mu.m.sup.2. The potential of the working electrode is sept, over a range to reduce each of the one or more gases, and at a rate to minimize cross-reactions between gases and their reduction products.

Abstract: An NOx sensor has the sensor element made of an oxide, the resistance of which is varied in response to an NOx component in a gas to be measured, and a measuring portion for measuring a resistance variation of the sensor element and for detecting an NOx concentration in the gas to be measured. A catalyst is arranged at an upstream side of a flow of the gas to be measured with respect reach to the sensor element, which makes a partial pressure ratio of NO/NO.sub.2 reach to an equilibrium state and removes a CO component from the gas to be measured. A heater for adjusting a temperature is arranged at a position close to the sensor element, which maintains temperatures of the sensor element and the catalyst constant. An O.sub.2 sensor is arranged at a position close to the sensor element so that the measuring portion can detect accurately the concentration of Nox in the measurement gas by reference to the resistance of the sensor element.

Abstract: A low cost room temperature electrochemical gas sensor with humidity compensation for sensing CO, alcohol vapors and other toxic analyte gases has a solid protonic conductive membrane with a low bulk ionic resistance. A sensing electrode and a counter electrode, optionally a counter electrode and a reference electrode, which are separated by the membrane, can be made of mixed protonic-electronic conductors, or can be made of a thin electrically conducting film such as platinum. A reservoir of water maintain the solid protonic conductive membrane at constant 100 percent relative humidity to compensate for ambient humidity changes. Embodiments of the inventive sensor also include an electrochemical analyte gas pump to transport the analyte gas away from the counter electrode side of the sensor.

Abstract: Sensors (10, 40) accurately measure the concentration of an oxide compound, such as nitrogen oxide NO.sub.x, in a gas mixture (11) which can include oxygen O.sub.2. The sensors (10, 40) each comprise a chamber (12, 42) adapted to receive the gas mixture (11) as well as first and second electrochemical cells (16, 17) for consuming oxygen and/or the oxide compound in the chamber (12, 42). The first electrochemical cell (16) comprises a first internal electrode (16a) inside the chamber (12, 42), a first external electrode (16b) outside the chamber (12, 42), and a first electrolyte body (14') therebetween. The second electrochemical cell (17) comprises a second internal electrode (17a) inside the chamber (12, 42), a second external electrode (17b) outside the chamber (12, 42), and a second electrolyte body (14") therebetween. The first and second electrolyte bodies (14', 14") are permeable to oxygen ions.

Abstract: The invention relates to the amperometric detection of nitrite ions and nitrogen monoxide by electrocatalytic reduction by means of electrodes (15) modified by an electronically conductive polymer film such as poly-(N-methyl pyrrole) doped by mixed heteropolyanions of formulas:[M.sup.III X.sup.1 W.sub.11 O.sub.39 (H.sub.2 O)].sup.n- or[M.sup.III X.sub.2.sup.2 W.sub.17 O.sub.61 (H.sub.2 O)].sup.7-in which M represents Fe, Rh, Al, Ga, In or Tl,X.sup.1 represents P or As and n is equal to 4,X.sup.1 represents Si or Ge and n is equal to 5, orX.sup.1 represents B and n is equal to 6, andX.sup.2 represents P or As.It also relates to the films and modified electrodes used.

Abstract: An electrode sensor which may be used to specifically and quantitatively measure nitric oxide is provided, as well as a method of preparing and using such an electrode sensor to measure nitric oxide concentration in solution. A nitric oxide (NO) microsensor based on catalytic oxidation of NO comprises a thermally-sharpened carbon fiber with a tip diameter of about 0.5-0.7 .mu.m coated with several layers of p-type semiconducting polymeric porphyrin and cationic exchanger deposited thereon. The microsensor, which can be operated in either the amperometric, voltammetric or coulometric mode utilizing a two or three electrode system, is characterized by a linear response up to about 300 .mu.M, a response time better than 10 msec and a detection limit of about 10 nM. The sensor of the present invention also discriminates against nitrite, the most problematic interferant in NO measurements.

Abstract: A low cost room temperature electrochemical gas sensor for sensing CO and other toxic analyte gases has a solid protonic conductive membrane with a low bulk ionic resistance. A sensing electrode and a count counter electrode, which are separated by the membrane, can be made of mixed protonic-electronic conductors. Embodiments of the inventive sensor also include an electrochemical analyte gas pump to transport the analyte gas away from the counter electrode side of the sensor. Analyte gas pumps for the inventive sensor include dual pumping electrodes situated on opposite sides of the membrane, and include a means for applying a DC power across the membrane to the sensing and counter electrodes. Another embodiment of the inventive sensor has first and second solid protonic conductive membranes, one of which has a sensing electrode and a counter electrode separated by the first membrane, and the other of which has dual pumping electrodes situated on opposite sides of the second membrane.

Abstract: The present invention provides electrochemical sensors for the detection of nitric oxide comprising a housing in which is disposed a working electrode, a reference electrode and a counter electrode. The electrochemically active surface of the working electrode preferably comprises RuO.sub.2. The nitric oxide electrochemical sensors of the present invention are capable of resolving nitric oxide concentrations at least as low as approximately 0.1 ppm and are well suited for use in medical environments because of their insensitivity to many other gases commonly used in medical environments.

Abstract: A sensor system accurately measures nitrogen oxide (NO.sub.x) in a gas mixture via the use of at least one electrochemical sensing cell and differential pulse voltammetry (DPV). The sensor system has a sensor with an electrochemical sensing cell for producing an electrical signal (current, voltage, etc.) indicative of an amount of the nitrogen oxide within the gas mixture. The sensing cell has an electrolyte interposed between an anode electrocatalyst and a cathode electrocatalyst. Significantly, a DPV mechanism is connected to the sensing cell for enhancing the sensitivity and selectivity of the electrolyte associated with the sensing cell.

Abstract: An in situ probe failure detection method for probes which deliver an electric signal on account of a change of the concentration of a substance to be measured. An example of such a probe failure may be caused by, for example, fouling of the membrane as the relative change in signal may be interpreted as a change in the concentration of the substance to be measured. More particularly, the method involves detecting the need for calibrating probes, which probes deliver an electric signal on account of a change of the concentration of a substance to be measured, characterized by: (a) subjecting the probe to a stepwise change of the concentration of the substance to be measured; (b) calculating the value of the probe response time constant t.sub.c of the obtained measurement curve with the help of the following main equation (1): t.sub.c dy/dt=-y+.alpha..sub.0 +.alpha..sub.1 t wherein t=time (time), t.sub.c =probe response time constant (time), y=substrate probe signal (mass volume.sup.-1), .alpha..sub.