Abstract: An oxygen sensor has a laminated body with a fluid sample inlet end and an electrical contact end, a fluid sample inlet, a substantially flat test chamber communicating with the fluid sample inlet where the test chamber is adapted to collect a fluid sample through the sample fluid inlet, a working electrode and a reference electrode within the test chamber, and a reagent matrix disposed on the working electrode where the reagent matrix contains an oxidase, a reduced form of a redox mediator and a peroxidase.

Abstract: A system and method for correcting the oxygen effect on oxidase-based analyte sensors includes an oxygen sensor with a working electrode, a reagent matrix disposed on at least the working electrode that contains a reduced form of a redox mediator, an oxidase and a peroxidase, an oxidase-based analyte sensor, a means for determining the oxygen concentration in a portion of a fluid sample using the oxygen sensor, means for determining an analyte concentration in another portion of the fluid sample using the oxidase-based analyte sensor, and means for using the oxygen concentration in the fluid sample to determine a corrected analyte concentration in the fluid sample.

Abstract: A strip dispenser has a strip magazine, a magazine spring, a strip vial component, and a cover. The strip magazine has a magazine open end and an outer magazine casing surrounding the strip magazine adjacent the open end for a predefined distance along the strip magazine where the magazine has a magazine volume with an open magazine top. The magazine spring is contained within the strip magazine. The strip vial component has a magazine receiving end, a closed end and a vial recess for slidably receiving the strip magazine between a first position and a second position where the vial recess has a shoulder portion spaced from the closed end and adjacent to and aligned with the open magazine top. The cover encloses the magazine open end and has a slit spaced a predefined distance from an edge of the cover where the slit is in communication with the magazine volume and the open magazine top and in spatial alignment with the shoulder portion.

Abstract: A disposable electrode strip for testing a fluid sample including a laminated strip with a first and second end, a vent, an open path for receiving a fluid sample of less than one microliter beginning from the first end and connecting to the vent, a working electrode, a reference electrode and a pseudo-working electrode embedded in the laminated strip within the open path and proximate to the first end, a reagent matrix coextensive within the open path and covering the three electrodes, and conductive contacts located at the second end of the laminated strip.

Abstract: A disposable biosensor for testing a fluid sample including a laminated strip with a first and second end, a reference electrode embedded in the laminated strip proximate to the first end, at least one working electrode embedded in the laminated strip proximate to the first end and the reference electrode, an open path for receiving a fluid sample beginning from the first end and connecting to a vent spaced from the first end, the open path being sufficiently long to expose the reference electrode and the working electrode to the fluid sample, and conductive contacts located at the second end of the laminated strip. The laminated strip has a base layer with a conductive coating, a reagent holding layer, a channel forming layer and a cover having an inlet notch at the first end. The working electrode contains a reagent having an enzyme.

Abstract: An improved biosensor having at least a first working electrode and a first electrode material disposed on the first working electrode. The first electrode material is a mixture made by combining at least one enzyme where the at least one enzyme is a capable of reacting with the analyte to be measured, a redox mediator capable of reacting with a product of an enzymatic reaction or a series of enzymatic reactions involving the at least one enzyme, a peroxidase capable of catalyzing a reaction involving the redox mediator where the redox mediator is oxidized, a binder and a surfactant.

Abstract: An electrochemical sensor for detecting the presence and amount of acetate in cell culture and fermentation media. The electrochemical sensor has a pH electrode, an internal reference electrode, a special high-tensile strength gas permeable membrane, and internal reference electrolyte such that acetate concentration can be measured using a pretreatment buffer having a pH of about 5.5.

Abstract: A static mixer for mixing substances under either laminar flow or turbulent flow conditions, or for mixing substances having a combination of laminar and turbulent flow conditions. The static mixer includes a first conduit operatively connected to a series of two or more mixing segments. The mixing segments include one or more splitting components for dividing the fluid stream into two or more flow streams, two or more flow branches wherein each of the flow branches receives one of the flow streams and wherein each of the flow branches operatively changes the cross-sectional shapes of their respective flow streams in preparation for layering and stacking the flow streams to each other, and a second conduit for receiving and stacking the two or more flow streams creating a layered unified fluid stream.

Abstract: A method of mixing substances under either laminar flow or turbulent flow conditions, or substances having a combination of laminar flow conditions. The method includes combining two or more initial fluidic substances into a combined fluid stream, dividing the combined fluid stream into two or more separate fluid streams, changing the shape of each of the two or more separate fluid streams in preparation for layering the two or more separate fluid streams together into a subsequent combined fluid stream such that each subsequent combined fluid stream has the same cross-sectional shape as the initial combined fluid stream and such that the cross-sectional area of the fluid stream is constant, and repeating the dividing, shaping and layering of the subsequent combined fluid stream at least one or more times.

Abstract: A method of determining the total carbon dioxide concentration in plasma (TCO.sub.2 plasma) directly from a whole blood sample involves adjusting total carbon dioxide concentration measured in the whole blood sample (TCO.sub.2 whole blood) using a volume dilution factor (VDF) to give a value that is equivalent to TCO.sub.2 plasma.

Abstract: A CO.sub.2 electrode can be calibrated with two PCO.sub.2 calibration standard solutions having known pH values and known bicarbonate ion source concentrations. An O.sub.2 electrode can be calibrated using air as one calibration standard and a solution containing an excess of an O.sub.2 depleting agent as a second calibration standard.

Abstract: Disclosed is a method of assaying a high concentration of a substance in a liquid sample with a polarographic cell. The cell contains an electrode assembly that includes a reference electrode and a hydrogen peroxide sensor electrode having a laminated membrane covering the liquid sample contacting face of the sensor electrode. The laminated membrane includes an outer membrane permeable to the substance and oxygen, an inner membrane permeable to hydrogen peroxide and located adjacent the face of the sensor electrode, and an enzyme layer between the inner and outer membrane; the enzyme in the enzyme layer can oxidize the substance to generate hydrogen peroxide.

Abstract: The magnesium ion content of a sample is determined by contacting the sample with a magnesium ion selective membrane including a 1,10-phenanthroline having an H group at positions 2 and 9. Examples of preferred 1,10-phenanthrolines include 4,7-diphenyl-1,10-phenanthroline, N-dodecyl-N-methyl-1,10-phenanthroline-4-carboxamide, 4-undecyl-1,10-phenanthroline, 4,7-diundecyl-1,10-phenanthroline and 5-nonyl-1,10-phenanthroline-4-carboxylate.

Abstract: An apparatus for correcting an initial measurement of the concentration of a first water soluble species dissolved in a water-based component of a biological fluid that also includes a second water soluble species and a volume occupying component, the initial measurement having been taken using an original sample of the fluid that had been diluted by an amount of additional aqueous solution to form a diluted sample is disclosed; the concentration of the second water soluble species is measured in an undiluted sample of the biological fluid to obtain a direct concentration and is measured using a diluted sample of the fluid to obtain an indirect concentration, and the initial measurement of concentration of the first species is adjusted based on a combination of the direct and indirect concentration determination of the second species.

Abstract: The occurrence of physical contact between a conductive probe and a surface of a liquid held in a container is detected as the probe is moved toward and eventually touches the liquid surface; a conductor is disposed on the other side of the container from the probe; an electrical signal is sent through the liquid between the conductive probe and the conductor, and the time when physical contact has occurred is determined based on when the resulting electrical signal which has passed through the liquid exceeds a threshold; and the threshold is determined based on the resulting electrical signal. In another aspect, the electrical signal is pulsed, and the resulting electrical signal is synchronously detected as the basis for determining when the physical contact has occurred.

Abstract: Correcting an initial measurement of the concentration of a first water soluble species dissolved in a water-based component of a biological fluid that also includes a second water soluble species and a volume occupying component, the initial measurement having been taken using an original sample of the fluid that had been diluted by an amount of additional aqueous solution to form a diluted sample is disclosed; the concentration of the second water soluble species is measured in an undiluted sample of the biological fluid to obtain a direct concentration and is measured using a diluted sample of the fluid to obtain an indirect concentration, and the initial measurement of concentration of the first species is adjusted based on a combination of the direct and indirect concentration determinations of the second species.

Abstract: Apparatus for removing fluid residue from an outer surface of a probe after it has been exposed to a fluid sample; the apparatus includes a wiper having a contact surface for wiping the residue from the outer surface of the probe, and a fluid flow path that cooperates with the contact surface for withdrawing wiped residue away from the contact surface and the probe; and a mechanism is provided for causing the contact surface to be swept along the outer surface of the probe. An apparatus for cleaning the outer surface of a probe after it is exposed to a fluid sample including a wiper for contacting the outer surface of the probe and a mechanism for causing relative motion between the wiper and the probe to wipe fluid from the outer surface.

Abstract: Apparatus for controlling the use of consumable accessory units with machines where a memory device associated with each accessory unit holds information concerning the accessory unit, and circuitry in the machine acts in response to the information.

Abstract: A two electrode assembly in a polarographic cell includes a sensor electrode and a silver/silver chloride reference electrode in which silver metal is in contact with a substantial reservoir of silver chloride.