Abstract: The present invention provides sensing electrodes and electrode assemblies for use in measuring the activity of ions in a fluid sample; measuring blocks which include a sensing module housing such sensing electrodes and a reference electrode; and a fluid analysis system which includes such measuring blocks.

Abstract: A testing module is provided having units which can be arranged seriatim to provide narrow through passageways linked to each other for quantitative determination of analytes passing through the units as by electrical testing with electrodes. Auxiliary passageways are preferably used in one unit to allow flushing of a first sample chamber without contamination from a second sample chamber. An electrode holder carries a membrane backed by a gel to aid in electrically linking the membrane to an electrode and to support the membrane in a substantially planar condition in use.

Abstract: A fluid arrangement for analyzing a fluid sample using an electrochemical measuring apparatus having an analyzing device with an inlet port and an outlet port, the outlet port connecting to an outlet tube, the inlet port connecting to an inlet tube having a sample fluid receiving end, and the inlet tube connecting at a junction along its length to one end of a fluid supply tube, which fluid supply tube is connected at its opposite end to at least one fluid source containing a fluid. In a first mode, the fluid from the supply source flows through the fluid supply tube to the junction and the fluid then flows simultaneously in a proximal direction and a distal direction within the inlet tube from the junction, and in a second mode, a fluid sample is drawn through the inlet tube past the junction and into the analyzing module.

Abstract: A testing module is provided having units which can be arranged seriatim to provide narrow through passageways linked to each other for quantitative determination of analytes passing through the units as by electrical testing with electrodes. Auxiliary passageways are preferably used in one unit to allow flushing of a first sample chamber without contamination from a second sample chamber. An electrode holder carries a membrane backed by a gel to aid in electrically linking the membrane to an electrode and to support the membrane in a substantially planar condition in use.

Abstract: Apparatus and a process for reducing peristaltic pump noise in a high impedance electrochemical measuring system by eliminating the noise at the pump source so as to minimize the effect of the noise on the precision and the response time of the measuring electrode. In a system having a high impedance measuring electrode connected to the elastomeric peristaltic tubing via a fluid conduit, a high impedance segment is disposed in the fluid conduit between the electrode and peristaltic tubing and means are disposed between the segment and peristaltic tubing for discharging the electrical noise generated by the action of the pump rollers over the peristaltic tubing. Preferably the discharging means is a conductive path electrically connected to an AC capacitive ground wherein the impedance of the capacitive ground is less than that of the segment. The segment may be a nonconductive liquid or gas such as air.

Abstract: Rapid and accurate whole blood analysis measurements are made with analysis systems of the potentiometric type that employ restricted diffusion type liquid junctions where the whole blood sample is flowed past sensing electrode and liquid junction at a velocity of at least one centimeter per second during a data acquisition interval that is at least twenty-five milliseconds in duration.

Abstract: An analysis system for measuring a plurality of parameters of a fluid sample comprises a housing, and a flow-through cell in the housing that has opposed surfaces with at least two ports in each surface. One of the ports is an inlet port, a second of the ports is an outlet port, and at least two of the ports are sensing ports. A sample flow path including a serpentine portion in the cell serially connects the ports and extends from a port in one surface to a port in the other surface and back to a port in the one surface, and a sensor is disposed in sealing engagement with each sensing port and forms a portion of the serpentine flow path so that sample fluid to be analyzed contacts a surface of each sensor.

Abstract: A reference liquid system for use with a chemical analyzer that has a plurality of ion selective electrodes comprises a plurality of reference liquids, each of which has a first salt component such that ions of a first element to be measured are present in a predetermined concentration, a second salt component such that ions of a second element to be measured are present in a predetermined concentration, and an error compensation salt component present in a concentration effective to adjust(a) the activity coefficient factor and/or(b) the junction potential factorto reduce the error involved in use of the compensated reference liquid to less than fifty percent of the error involved in use of a corresponding uncompensated reference liquid.

Abstract: A clinical analyzer system flows a small volume (less than 200 microliters) of liquid sample to be analyzed from an inlet port past a sensor array to a series of analysis chambers. The sensor array includes two optical sensor units that are spaced a fixed distance apart, and each sensor unit transmits a beam of infrared radiation through the flow tube for sensing by a detector. Each detector output has a low value when blood is in the flow tube, an intermediate value when air is in the flow tube, and a high value when a clear liquid is in the flow tube. Control logic senses changes in the outputs of the detectors and accurately indicates gas-liquid interface transitions. The noninvasive system accurately locates leading and trailing edges of samples of biological fluids to be analyzed, monitors the integrity of those samples, and distinguishes between types of sample liquids processed by the analyzer.

Abstract: A blood gas control liquid comprises a stable oil-in-water emulsion that has an oxygen solubility coefficient of at least 10 ml O.sub.2 per 100 ml emulsion and a viscosity of less than 10 centipoises. The emulsion includes water, 5-40 percent by volume of a water-insoluble non-protein compound material, 0.25-10 percent by volume of a nonionic surfactant, a pH buffering agent and a preservative agent which is substantially non-reactive with the pH buffering agent. A preferred blood gas control liquid has a density of about 1.08. The blood gas control liquid has a pH in the range of 7-8, a partial pressure of carbon dioxide in the range of 15-80 millimeters Hg, and a partial pressure of oxygen in the range of 20-600 mm Hg.

Abstract: A one-piece disposable electrode comprising a sealed chamber containing an electrolyte solution, silver-silver chloride conductor in the electrolyte solution in the chamber and a cast-in-place membrane essentially flush with an exterior wall of this chamber for exposure to a biological fluid whose ion content is to be measured.

Abstract: An analysis system for measuring a plurality of parameters of a fluid sample comprises a housing, and a flow-through cell in the housing that has opposed surfaces with at least two ports in each surface. One of the ports is an inlet port, a second of the ports is an outlet port, and at least two of the ports are sensing ports. A sample flow path including a serpentine portion in the cell serially connects the ports and extends from a port in one surface to a port in the other surface and back to a port in the one surface, and a sensor is disposed in sealing engagement with each sensing port and forms a portion of the serpentine flow path so that sample fluid to be analyzed contacts a surface of each sensor.

Abstract: An analysis system for measuring a plurality of parameters of a fluid sample comprises a housing, and a flow-through cell in the housing that has opposed surfaces with at least two ports in each surface. One of the ports is an inlet port, a second of the ports is an outlet port, and at least two of the ports are sensing ports. A sample flow path including a serpentine portion in the cell serially connects the ports and extends from a port in one surface to a port in the other surface and back to a port in the one surface, and a sensor is disposed in sealing engagement with each sensing port and forms a portion of the serpentine flow path so that sample fluid to be analyzed contacts a surface of each sensor.

Abstract: A blood gas control liquid comprises water, 5-40 percent by volume of a water-insoluble perfluorinated compound material that has an oxygen solubility coefficient, at one atmosphere pressure, 25.degree. C., and a volumetric proportion of 15 percent of at least 10 ml O.sub.2 per 100 mL emulsion, 0.25-10 percent by volume of a nonionic, fluorocarbon-based surfactant, a preservative agent and a buffering agent which is substantially non-reactive with said preservative agent. The blood gas control liquid has a pH in the range of 7-8, a partial pressure of carbon dioxide in the range of 15-80 millimeters Hg, and a partial pressure of oxygen in the range of 20-600 mm Hg.

Abstract: A system for analyzing a biological fluid specimen or the like includes an analysis chamber and an electrochemical electrode measuring system connected in sensing relation to the analysis chamber. A flow network connects a sample inlet port and an auxiliary fluid reservoir to the analysis chamber. The flow network includes a sample line connected between the sample inlet port and the analysis chamber and an auxiliary manifold connected to the auxiliary fluid reservoir. A positive displacement pump is connected in the sample line between the analysis chamber and a waste outlet port.