Abstract: A process and device for quantitative determination of analyte concentrations in liquid samples. The device includes one or more bibulous matrices constructed and arranged to essentially eliminate sample volume sensitivity from analyte determinations. In accordance with the present invention, the device includes one or more test reagent-treated bibulous matrices covered at least partially by an impermeable coating or film. A liquid sample is applied to the uncovered portion of the bibulous matrix such that the liquid sample is metered into the bibulous matrix by the impermeable coating or film. The sample chromatographs through the bibulous matrix until the matrix is saturated with liquid. The process is essentially sample volume independent, providing more uniform and accurate quantitative analyte determinations.

Abstract: The present invention provides a stable, convenient solid state test device for the determination of ethanol in an aqueous test sample, a method for its preparation and a method for its use. The use of carrier matrix incorporated with alcohol oxidase, a peroxidatively active substance and a suitable chromogenic indicator for the determination of ethanol in aqueous samples such as body fluid samples (e.g., serum, urine or saliva) is part of the invention. The invention provides a method of incorporating the enzyme alcohol oxidase and a peroxidatively active substance into a carrier matrix with a chromogenic indicator system capable of providing a detectable response to the presence of at least 100 mg/dL ethanol in less than about 5 minutes. The method involves either (a) the use of a specialized incorporation procedure or (b) the addition of an azide to the test device.

Abstract: Proteins such as enzymes are attached directly to a polyamide or cellulose hydrate carrier. Attachment can be carried out by impregnation of the carrier with a protein solution. The carrier can be in the form of a membrane, and the polyamide can be nylon. Resulting carrier-bound proteins find utility as biocatalyst, as test strips or as chromatography materials. In a preferred embodiment, a polyamide or cellulose hydrate membrane carrier is impregnated with an enzyme selected from peroxidase, glucose oxidase, diaphorase and glucose dehydrogenase and then dried, coated with a luminol solution and again dried. The resultant membrane can be used for glucose determination by measuring chemiluminescence produced when the membrane contacts a glucose solution.

Abstract: The present invention relates to new chromogenic amino acid esters and peptide esters of hydroxybenzo(iso)thiazoles and hydroxybenzopyrazoles and the use of the new esters as substrates for the analytical detection of esterolytic and/or proteolytic enzymes, for example in body fluids, the esters being incorporated into test agents, in particular test strips, in a suitable manner. The new esters are preferably used for the detection of leukocytes, in particular in urine.

Abstract: A process for preparing test aids for detecting substances to be analyzed by means of redox reactions containing single component oxidation indicators as the indicator substance in which oxidizable aromatic amine or hydrazino compounds, which are not capable of coupling with themselves, are added as decolorants.

Abstract: Separation device and method for the fractionation and separation of finely divided solid particulate material suspended in a liquid are disclosed. The separation device comprises upper and lower portions which are joined together to form an inner cavity retaining liquid and a capillary gap which extends outwardly radially from said cavity. During rotation solid particles present in the suspending liquid pass outwardly along and/or become entrapped in the capillary gap(s).

Abstract: A method of making a multilayer analytical test element comprises providing layers at least one of which is responsive to detect a ligand in a liquid sample, or to detect the ligand binding capacity of the sample, and at least one other layer that is fusible when subjected to sonic energy, arranging the layers one on top of the other together to form a composite blank of layers, subjecting the composite to ultrasonic or laser energy to cut the composite to the desired dimension of the test element and to simultaneously weld the layers at the edges thereof, said energy softening and fusing the fusible layer to thereby bond the layers together.

Abstract: Test devices are disclosed in which the reagent matrix area(s) attached to a substrate are protected axially in the direction of the elongated substrate by a sloping surface(s) adjacent to each matrix area extending to the identical height of the matrix material. The resulting surface(s) protects said matrices from damage, particularly during wiping operations during which excess liquid and/or material is removed from the matrices.

Abstract: A novel compound useful in detecting leukocytes, esterase and protease in a test sample. The compound has the structure ##STR1## in which: A is an acid residue, R is lower alkyl, aryl, carboxyl, carboxyl ester, amido or cyano, R* is H or lower alkyl, and X is O, S, or NR', in which R' is H, lower alkyl or aryl.

Abstract: The precision in reflectance or absorption measurements used to determine the presence and concentration of a component in an assay liquid is unexpectedly increased to essentially eliminate the variability of different reactant carriers and variability in reflectance or absorption instruments by including, either within the reactant carrier or within the assay liquid sample, in addition to a primary color forming or color changing indicator, a secondary inert colorant compound or dye having a light absorption wavelength peak separated from a light absorption wavelength peak of the primary indicator or chromogen by at least 80 nm. To achieve the full advantage of the present invention, the colorant material or marker should be inert to the reactant system in the carrier and should be inert to the assay liquid to provide a light reflectance or light absorption response essentially distinct from the light reflectance response of the primary chromogen to compensate for measurement variability.

Abstract: A method for controlling a liquid volume flowing onto a reactive surface which includes a sample application port, two systems of capillary channels, a reaction chamber, and an overflow chamber. The liquid sample to be analyzed is applied to the sample application port which gives the liquid entry to a capillary channel leading to the reaction chamber which contains a material capable of detecting the component of interest in the liquid. When the reaction chamber is filled, the remaining liquid will flow through another capillary channel to an overflow chamber. The capillary channel leading to the overflow chamber is controlled so that liquid cannot flow back into the reaction chamber.

Abstract: Agent for the detection of esterolytic and/or proteolytic enzymes, containing (a) an amino acid ester or peptide ester of a phenol, as the chromogenic enzyme substrate, and (b) an alcohol as the substance which accelerates the enzymatic cleavage of the amino acid ester bond or peptide ester bond of component (a), characterized in that it contains a salt as the accelerating substance.

Abstract: A device for making accurate, reproducible light reflectance measurements on an optically nonuniform specimen comprises means for holding the specimen in a fixed position. In one embodiment the specimen is illuminated by light sources that are arranged at acute angles relative to the specimen and (360.degree./N.+-.1.degree.) apart in azimuth, where N=the total number of light sources. The light sources are sequentially energized and deenergized to illuminate the specimen. A light detector receives light reflecting from the surface and generates an electrical signal, which is subsequently processed. In another embodiment the light sources are arranged in pairs in which the two light sources in a pair are simultaneously energized and deenergized and the pairs are sequentially energized and deenergized. A method for measuring reflected light is also provided.

Abstract: Agent for the detection of esterolytic and/or proteolytic enzymes, containing (a) an amino acid ester or peptide ester of a phenol, as the chromogenic enzyme substrate, and (b) a substance which accelerates the enzymatic cleavage of the amino acid ester or peptide ester bond of component (a), characterized in that it contains a polyamino acid with a molecular weight of between 1,000 and 2,000,000 as the accelerating substance.

Abstract: A test strip with a sample absorption capacity which can be preselected comprises a support member capable of supporting along at least two edges a reagent strip in which the support member also has absorbent material positioned to remove excess sample applied to the reagent strip. In a preferred embodiment an intermediate layer is also supported by the support member and positioned above the reagent strip. The intermediate layer removes components of the sample which would otherwise interfere with the analysis being made in the reagent strip. In a further embodiment of the invention a cover is applied to the support member, wherein the cover contains an opening for introduction of sample material.

Abstract: A test means for detecting the presence of a specific ion in an aqueous test sample and for determining its concentration comprises a substantially nonpolar, nonporous carrier matrix which is incorporated with an ionophore capable of selectively forming a complex with the ion under analysis. In addition, a counterion reporter substance is provided separately, which is capable of producing a detectable response, such as a change in or appearance of color or fluorescence in the carrier matrix. In use, the test sample containing the counterion reporter substance is contacted with the test means, the test means is washed and any detectable response associated with the test means is determined.

Abstract: A method of calibrating reflectance measuring devices, such as spectrophotometers, that incorporate automatic gain or sensitivity setting capability. According to the method, offset reflectance and reflectance of a secondary reflectance standard for several wavelengths are calculated and stored in a memory of a reflectance measuring device. A secondary standard is mounted in the reflectance measuring device and reflectances at a selected wavelengths from the secondary standard are read prior to measurement of the reflectance of the test sample. The stored offset reflectance and secondary reflectance for the operational wavelength are used to calculate true reflectance of the test sample.

Abstract: The present invention relates to new chromogenic amino acid esters and peptide esters of hydroxybenzo(iso)thiazoles and hydroxybenzopyrazoles, processes for their preparation and the use of the new esters as substrates for the analytical detection of esterolytic and/or proteolytic enzymes, for example in body fluids, the esters being incorporated into test agents, in particular test strips, in a suitable manner. The new esters are preferably used for the detection of leukocytes, in particular in urine.