Abstract: A new family of fluorescent antibodies (FAB) and a method for their synthesis is disclosed for use in an apparatus and method wherein the effects of background fluorescence are virtually eliminated from fluorescence measurements. The novel fluorescent antibodies consist of antibodies conjugated with rare-earth chelates which have unique fluorescent properties. These fluorescent antibodies are useful because when excited with short pulses of light, they exhibit fluorescent decay times which are much longer than typical background fluorescence at room temperature and with a spectral width far narrower than typical background fluorescence.

Abstract: There is disclosed a "cold", i.e., non-radioactive (stable) isotope method for the immunoassay of biological compounds. The method uses selenium as the tracer label in compounds which compete in reaction with a conjugating compound and thus yield a solution for analysis which is a mixture of complexes of the conjugating compound with the selenium labelled and unlabelled compound. The nonradioactive isotope can be analyzed using fluorimetric determinations with proper preparatory treatment or atomic adsorption. Selenium is particularly unique in its adaptability to this assay because of its great compatibility with biochemicals, e.g., it has an atomic size and structure and chemical properties very close to that of sulfur and it readily forms compounds and small adducts with carbon and hydrogen containing compounds. Selenium is also ideally suited for use in this assay because it can be quantitatively detected at extremely low concentrations, e.g., the lower detection limit is presently about 10.sup.-9 to 10.

Abstract: In a method for detecting flaws in the surface of a workpiece, initially microcapsules containing a fluorescent dye are deposited on the surface. After removal of excess microcapsules from the surface in order to reduce background fluorescence, the surface is visually inspected under ultraviolet light. The method overcomes many of the disadvantages of conventional inspection procedures, e.g., by eliminating use of emulsifiers and by materially shortening processing time.

Abstract: A therapeutic composition suitable for extracorporeal treatment of whole blood comprises a dialyzable chemotherapeutic agent and a dialyzable fluorescable tracer means. The removal rate of the fluorescable tracer compound from treated blood during hemodialysis is a function of the removal rate of unreacted chemotherapeutic agent present. The residual chemotherapeutic agent concentration after hemodialysis is ascertained by measuring the concentration of the fluorescable tracer compound in a dialysate using fluorometric techniques.

Abstract: A plasma or flame spraying method is provided for applying a ceramic or metallic UV sensitive indicating coating onto a metal substrate. Particle size control of the ingredients used in the plasma or flame sprayable mixture has been found to enhance the fluorescence of the resulting indicating coating.

Abstract: Dual coated erosion resistant metal or ceramic structures are provided having an interior adherent indicating metallic or ceramic layer containing a UV sensitive phosphor and an exterior ceramic or metallic protective coating. A method of making such dual coated structures also is provided involving the plasma or flame spraying of blends of particulated metal powder or metal oxide powder and a metal oxide UV sensitive phosphor onto the surface of the metal or ceramic structure.

Abstract: An inspection system for ascertaining the surface of a glass sheet that contacted the molten metal bath during production of the glass by the float process and thus has traces of fluorescent metal or metal oxides thereon. The system employs a device for sensing the presence of a glass sheet and activating an ultraviolet light, which is modulated and illuminates the surface of the glass sheet. A visible light detector intercepts light fluorescing from the illuminated sheet surface, producing a signal which is processed by an electronic network for indicating the presence of metallic oxides on the sheet surface. When fluorescence is detected the ultraviolet light is extinguished and when fluorescence is not detected an alarm is activated.

Abstract: Methods for detection of the presence or absence of water leaks in building roofs and for tracing any leaks to the zone or area thereof in the roof by applying on all or part of the roof fluorescent dye-containing water, shining a fluorescence-inducing light, e.g., actinic or U/V light, onto the underside of the roof, its support structures, roof-penetrating structures and/or surfaces of walls beneath the roof, tracing the path or paths of fluorescence (if present) along the underside of said roof, and/or roof-penetrating structures, and/or roof support structures, and/or the building wall(s) to or near the point of origin of the area or zone of water leakage through said roof, and optionally applying the fluorescent dye-containing water onto the roof in the form of a spray in a fast-moving air stream or as a water jet or jet-spray to simulate wind-driven rain.

Abstract: A standard specimen for calibrating an ultraviolet scanning system of the type used to detect surface flaws in workpieces by penetrant testing including a piece of glass which has the characteristic of emitting fluorescent radiation upon excitation by ultraviolet light, and a heat conductive carrier element rigidly supporting the piece of glass therein. The standard specimen provides a means for confirming instrumentation stability despite changes in temperature.

Abstract: Thyroid hormones such as thyroxine and triiodothyronine are assayed in biological fluid samples by a competitive binding analysis in which a fluorescent label is used. Upon formation of complexes, the fluorescence of the labelled compound is released, and the hormone can be assayed by measuring the fluorescence of the mixture and comparing the result with standard data. Fluorescein is the preferred label. The process can be operated in a continuous flow manner.

Abstract: A method is provided for preparing immunoassay reagents involving labeled members of specific binding pairs substantially enriched relative to contaminating labeled materials. The method involves conjugating a member of a specific binding pair to a support by a covalent bond which is cleavable under mild conditions to provide a binding pair member-support conjugate. Combining the binding pair member-support conjugate with a labeled composition containing the reciprocal member of the binding pair, so that the labeled reciprocal member becomes bound to the support through the binding of the specific binding pair. Separating the support to which is bound the labeled member from the remaining labeled material and then cleaving the bond joining the labeled specific binding pair to the support to provide labeled reagent for immunoassays.

Abstract: A method for detecting leaky ampules filled with a liquid such as a parenteral solution. The ampules to be tested are immersed in a solution containing a short-lived radionuclide, and a pressure differential is imposed between the solution containing the radionuclide and the parenteral solution or other liquid contained in the ampules. The ampules are then removed from solution, decontaminated to remove any solution adhering to the outer surface and pores thereof, dried, and finally examined for electromagnetic radiation, preferably gamma radiation, emanating from the interior of the ampules which would indicate a leaky condition thereof.

Abstract: Immunoassays are provided employing antibodies and fluorescer-quencher (F-Q) chromophoric pair, wherein one or both of the chromophoric pair are bonded to antibodies. Depending on the particular ligand of interest, various reagent combinations can be employed, where the amount of quenching is directly related to the amount of ligand present in the assay medium.In carrying out the assay, the unknown and antibody specific for the ligand of interest to which is bound one of the F-Q pair, are combined in an aqueous buffered medium. Depending on the protocol, different assay reagents are employed in the aqueous buffered medium: (1) ligand analog bonded to the other of the F-Q pair; (2) antibodies specific for the ligand to which is bound the other of the F-Q pair or; finally, (3) a combination of a plurality of ligands bonded together through linking groups to a hub molecule, usually a polymer, in combination with antibody bound to the other of the F-Q pair.

Abstract: A system for detecting and identifying the composition of a material, such as semiconductor wafers and chips, subject to one or more stages of processing. The material is laser irradiated to induce molecular fluorescence with means to detect the decay rate of the fluorescence. The decay rate is then compared with a decay record of fluorescence of acceptable modifications of the material, inclusive of amalgamated contaminants or impurities (e.g. doped regions) to determine the state of the modification of the material.

Abstract: A method of detecting antibodies to native deoxyribonucleic acid (n-DNA), anti-nuclear antibodies, antibodies to non-histone containing protein, rheumatoid factors, antibodies to thyroglobulin, and an immunofluorescent assay for such detection is described.

Abstract: Background fluorescence which interferes with the measurement of an analyte in fluorescent immunoassays in serum samples is substantially diminished by treating the serum sample with a sufficient amount of a peroxidic compound, either organic or inorganic, for a time sufficient to reduce the background fluorescence contributed by serum components. The peroxidic compound is readily quenched, without adversely affecting the assay composition.

Abstract: A method of detecting antibodies to native deoxyribonucleic acid (n-DNA), anti-nuclear antibodies, antibodies to non-histone containing protein, rheumatoid factors, antibodies to thyroglobulin, and an immunofluorescent assay for such detection is described.

Abstract: Deuterium tagging in an amount at least ten (10) times the natural abundance of the deuterium isotope occurrence is disclosed. A composition of matter, including the group consisting of hydrogen containing compounds having at least one atom which is not oxygen and at least about ten (10) times the naturally occurring deuterium is disclosed. Preferred use is set forth in tagging explosives. A method of detecting the tagged article, such as explosives concealed in airline luggage includes subjecting tagged compounds with energy quanta sufficient to carry out the reactionD.fwdarw.n+p-2.23 MeVand detecting the number of neutrons generated is disclosed where n is a neutron, p is a proton and 2.23 MeV is the threshold energy required for the reaction. The apparatus, including a conveyor and a vertically scanning shutter is disclosed in combination with a linear accelerator for generating the X-ray energy in the order of 4 MeV and a boron triflouride proportional counter for detecting neutrons.

Abstract: Disclosed is a method of detecting a cured silicone coating applied to a paper substrate or the like in web form, comprising adding an effective amount of a fluorescent pigment to the silicone coating formulation to be applied to the substrate, applying the coating to the substrate, curing the silicone coating, scanning the coated surface of the substrate with a UV light source, and detecting the fluorescence of the coating. Also disclosed is the coated paper product with which the method of the invention can be employed.

Abstract: A method of and apparatus for inspecting the threads of tubular elements for flaws, cracks and the like are disclosed. The invention is particularly useful in performing thread inspections of the box and pin ends of drill collars according to known processes using a fluorescent solution and ultraviolet radiant energy. An inspection unit is provided which encloses the threads to be inspected in a light-excluding manner and houses a source of ultraviolet energy. The threads are visually inspected through an aperture in the inspection unit by either rotating the inspection unit or the tubular element to be inspected.

Abstract: The invention provides a reaction product of chrysotile asbestos with an antigenic serum protein, preferably albumin, that has particular utility as an antigen in producing antibody to asbestos. The reaction product of asbestos with an antigenic serum protein also can be used in a method for producing an antibody toward asbestos by immunizing a laboratory animal with the reaction product, of asbestos and a serum protein, allowing it to remain in the blood of the animal for a sufficient period of time and thereafter recovering antibody globulins from the laboratory animal.

Abstract: Additives, such as stabilizers, antioxidants, anti-static agents etc., are intimately blended with an irradiation-responsive substance, such as an optical brightener, and incorporated in a thermoplastic polymeric material which is then subjected to irradiation to determine the degree of uniformity of distribution of the additive-brightener blend.

Abstract: A method of inspecting electrical devices such as integrated circuit devices which have conductors covered by a protective layer of passivating material to determine the quality of the protective layer includes treating the circuit with a fluorescein containing dye and exposing the treated device to UV radiation while applying a voltage between two conductors. Fluorescence is observable in well passivated areas of the device but not in unpassivated or inadequately passivated areas. When a device is tested before dicing from a wafer, adjacent devices to which no voltage is applied fluoresce in both passivated and unpassivated areas.

Abstract: Methods and compositions are provided for improved protein binding assays by preparing compositions having indirectly labeled ligands substantially free of label conjugated to materials other than the indirectly labeled ligand. The method for preparing the compositions involves employing a monovalent receptor to which the label is conjugated and combining the monovalent receptor labeled conjugate to the ligand, either in pure or impure form. The mixture is then segregated according to molecular weight and the ligand conjugated to the labeled receptor isolated. This conjugate may then be directly used as a reagent in a protein binding assay, where the assay mixture is substantially free of label other than labeled receptor bound to ligand.The labels will be for the most part of relatively low molecular weight, while the receptor is preferably a Fab fragment.

Abstract: The present invention encompasses a method for enumerating microbial cells in an aqueous test sample comprising: fluorescently labeling the microbial cells in test sample intermixing a known amount of monodispersed fluorescently labeled beads of about cell size into the test sample, and determining the ratio of bacterial cells to fluorescently labeled beads, the reagents for practicing this method. The methods and reagents of the present invention are particularly useful in counting bacterial cells in urine.

Abstract: Apparatus for the detection and analysis of particulate material carried in a fluid stream comprising a sampling device through which the fluid stream may be passed, said sampling device incorporating means for arresting and carrying an accumulation of particles restrained from flow in the fluid stream, means for directing ultra-violet radiation onto the sampling device at a location where the accumulation of particles results, and means whereby optical radiation analysis may be performed of the radiation emitted by the accumulation of particles consequent upon their excitation by the ultra-violet radiation means.

Abstract: Ferrite particles having a plurality of distinct Curie temperatures are encapsulated within a glass matrix to provide tagging material especially useful in identifying explosive materials even after detonation. In one embodiment, phosphor is dispersed within the glass matrix or an intrinsically fluorescent glass is employed to facilitate visual identification and collection of tag particles following detonation. The tags are also usable in tagging other articles, especially where harsh environmental conditions are likely to be encountered.

Abstract: Method for rapid and accurate weight determination of molten metal in a slag-containing bath preferably without any necessity for direct gross weighings in a hostile steel works environment or otherwise, by the addition to the molten bath of a known weight amount of a "trace" element (preferably of a type which is completely diluted in the molten metal, to the practical exclusion of the slag); awaiting the even dispersal of the trace element in the molten metal (aiding the speed of dispersal by promoting a boiling action, if necessary); taking a sample of the molten metal; analyzing the sample to determine the weight percent of trace element in the molten metal (for example by spectrometric analysis); and determining the weight of the metal from the known values of weight of the trace element added and its weight percent in the molten metal after addition.

Abstract: A liquid dye penetrant composition for use in nondestructive testing of objects to locate cracks and other defects or flaws therein, said composition comprising (1) a nonionic surfactant, such as an ocyalkylated aliphatic alcohol, (2) a small amount of a dye soluble in the surfactant and (3) a substantial and preferably a major proportion, of a high boiling narrow-cut isoparaffinic solvent consisting essentially of a mixture of isoparaffins having a chain length of about 10 to about 17 carbon atoms, and an average chain length of about 13 to about 14 carbon atoms, as extender. Such composition is applied to the surface of an object containing cracks and other defects, water is applied to the surface of the object to remove excess liquid dye penetrant composition from the surface without removing such penetrant from such cracks and other defects, and with or without a developer, the surface of the object is viewed under suitable lighting conditions, e.g.

Abstract: Immunoassays are provided employing antibodies and a fluorescer-quencher (F-Q) chromophoric pair, wherein one or both of the chromophoric pair are bonded to antibodies. Depending on the particular ligand of interest, various reagent combinations can be employed, where the amount of quenching is directly related to the amount of ligand present in the assay medium.In carrying out the assay, the unknown and antibody specific for the ligand of interest to which is bound one of the F-Q pair, are combined in an aqueous buffered medium. Depending on the protocol, different assay reagents are employed in the aqueous buffered medium: (1) ligand analog bonded to the other of the F-Q pair; (2) antibodies specific for the ligand to which is bound the other of the F-Q pair or; finally, (3) a combination of a plurality of ligands bonded together through linking groups to a hub molecule, usually a polymer, in combination with antibody bound to the other of the F-Q pair.

Abstract: A process for the nondestructive testing of ceramic objects to detect the presence of defects and micro-cracks in the surface in which a solution of silver nitrate is applied to the surface of the object which penetrates into the surface defects, drying the object so that the silver nitrate remains in the defects, and preparing an X-ray radiograph whereby any defects and micro-cracks will appear in the radiograph.

Abstract: A novel sensitive method for determining qualitatively and quantitatively the presence of a wide variety of physiologically active organic compounds (ligand) and their receptors is provided. The method employs a reagent whch involves bonding a compound having structural similarity to the compound to be determined (ligand analog) to a fluorescing compound. The unknown compound is referred to as a ligand, the conjugate of the structurally similar compound and fluorescer is referred to as ligand analog-fluorescer, and compounds which recognize a specific structure and bind to such structure are referred to as receptors and are normally antibodies.The fluorescer which is chosen will have either a change in quantum yield or a change in its emission and/or absorption spectra or all of them, when the ligand analog-fluorescer is bound to receptor, as compared to being unbound.

Abstract: A water washable substantially biodegradable dye penetrant composition having excellent sensitivity and high stability, for use in non-destructive testing of objects to locate voids and defects therein, said composition consisting essentially of an organic dye, preferably a fluorescent dye, and a carrier or solvent for said dye, in the form of certain ethoxylated linear alcohols, particularly the biodegradable nonionic surfactants comprised of ethoxylates of a mixture of secondary alcohols having linear alkyl chains of from 10 to 17 carbon atoms. In the method of application of the dye penetrant compositions, such composition is applied to the surface of an object containing cracks and flaws, water is applied to the surface of the object to remove excess liquid dye penetrant composition from the surface without removing such penetrant from the cracks and defects, and with or without a developer, the surface of the object is viewed under suitable lighting conditions, e.g.

Abstract: A novel composition of matter, process and apparatus is provided for distinguishing and absolutely counting leukocytes, erythrocytes, reticulocytes, and other cells as well as differently counting and classifying the different types of leukocytes. The composition of matter comprises a plurality of compatible dyes for uniquely distinguishing leukocytes, erythrocytes, reticulocytes, and other cells randomly distributed in a medium. At least one of the dyes imparts a characteristic fluorescence to all leukocytes stained therewith. The nature of the dye composition is such that when the stained leukocytes are irradiated with radiation having the characteristic absorption wavelengths of each dye, the relative intensities of the light emitted and/or transmitted by each leukocyte type defines that particular leukocyte type.

Abstract: The present invention provides an apparatus in which one or more light concentrators comprising thin layers of transparent solid or liquid materials with embedded fluorescent centers are combined with absorbers in order to convert solar light into heat energy at high temperatures.

Abstract: A fluorometric system to determine the kind and amount of substances derived from a biological fluid (e.g., serum or urine) or tissue in which the substances to be detected (e.g., antigen, antibody, hormone or enzyme) are coated onto a substrate surface in fluorescent form. Multiple coating areas of different samples may be employed. The fluorometric system includes a source of filtered light to excite fluorescence, an optical system for conducting the excitation light to such coating, and optical systems for receiving emitted fluorescence and for detecting the same. The system efficiency and optical characteristics disclosed avoid photo-bleaching; limit fading; and are especially adapted to provide accurate surface reading fluorometry.

Abstract: The present invention relates to a refractory materials used in processing molten metals comprising combining at least one of the refractory materials selected from the group consisting of SiO.sub.2, Al.sub.2 O.sub.3, MgO, ZrO.sub.2 with an activatable element for labeling which has an activation cross section of over 1 barnand apparatus made from a plurality of differently labeled refractory components.

Abstract: Dry developer composition in powder form and process for using same in the inspection of metal surfaces for cracks and defects open to the surface by the penetrant process. The powder composition of this invention has special significance in providing easier to see flaw indications when used with the fluorescent penetrant method of inspection.

Abstract: A rapid, non-destructive system and method for insitu detection and identification of luminescent organic particulates or films on non-luminescent devices, such as semiconductor wafers and chips. The major optical components of the system comprises a luminescent vertical illuminator, an image device and a detector. The method is based on the principle that a very large number of organic materials luminesce when excited by ultraviolet radiation. By scanning the luminescent emission spectra of the known organic materials used in manufacture, a characteristic curve of intensity versus wavelength is obtained and matched to curves of known organic materials, thereby permitting detection and identification of the particulates.

Abstract: The approximate concentration of a carburetor additive in a motor fuel is determined by a paper chromatographic method.

Abstract: A method and apparatus for detection of monoalkylhalides is disclosed. This apparatus contemplates detection of extremely small traces of monoalkylhalides through the nucleophilic substitution of a heavier halogen (preferably iodine) by introducing a sample gas having a monoalkylhalide therein in trace concentrations to be detected and passing it through a closed container providing a surplus of heavier halide ions. An exemplary source of a heavier halide is a container having an alkali iodide therein heated to a temperature sufficiently elevated to initiate iodine disassociation, such as 250.degree. C. An exchange of an iodine for a covalently bound fluorine or chlorine atom is achieved. The monoalkylhalide then has a larger molecular diameter and more complex electronic structure than that originally provided. It also has an enhanced affinity for slow or low energy electrons. This enhances the operation of detection equipment exemplified by an electron capture detector.

Abstract: Perinatal lung maturity is evaluated by determining the fluorescence polarization of a sample of pulmonary effluent containing pulmonary surfactant labeled with a fluorescent dye. The sample is excited with polarized radiation for causing the dye to fluoresce. I.sub.81 and I.sub.195, the intensities of fluorescence polarized in directions parallel to, and perpendicular to, the direction of polarization of the excitation radiation, are measured. From these measurements, the fluorescence polarization P, where P = (I.sub..parallel. - I.sub..perp.)/(I.sub..parallel. + I.sub.195), is determined. The value of P, which is functionally related to the microviscosity of the constituents of the surfactant, has been found to decrease with perinatal lung maturity. When the sample is amniotic fluid containing fetal pulmonary effluent, the evaluation of lung maturity can be carried out antepartum. Postpartum evaluation can be carried out by sampling neonatal tracheal or pharyngeal aspirates.

Abstract: Dry developer composition in powder form for use in penetrant inspection of surface flaws in bodies, consisting essentially of silica, preferably fumed silica, e.g. the material marketed as Cab-O-Sil M-5, and talc, particularly the powder marketed as Desertalc Mikro 507, in certain relative proportions. The resulting powder developer is particularly effective when employed in a dye penetrant inspection process comprising applying to a part surface a fluorescent penetrant, and especially a dye penetrant containing as carrier for the dye a biodegradable surfactant comprised of certain aliphatic oxyalkylated alcohols, followed by application of such dry developer to the part surface to provide bright fluorescent indications of surface flaws when inspected under fluorescent illumination.

Abstract: A fluorometric system to determine the kind and amount of substances derived from a biological fluid (e.g., serum or urine) or tissue in which the substances to be detected (e.g., antigen, antibody, hormone or enzyme) are coated onto a substrate surface in fluorescent form. Multiple coating areas of different samples may be employed. The fluorometric system includes a source of filtered light to excite fluorescence, optical systems for conducting the excitation light to such coating, and optical systems for receiving emitted fluorescence and for detecting the same. The system efficiency and optical characteristics disclosed avoid photo-bleaching; limit fading; and are especially adapted to provide accurate surface reading fluorometry.

Abstract: Variable sensitivity biodegradable water washable dye penetrant compositions for use in non-destructive dye penetrant inspection of parts, such compositions basically consisting essentially of an organic dye, preferably a fluorescent dye, and a carrier or solvent for said dye, in the form of a surfactant comprised of certain straight chain, primary, aliphatic oxyalkylated alcohols, particularly biodegradable surfactants comprised of the nonionic condensation products of linear primary aliphatic alcohols having from 10 to 18 carbon atoms, with ethylene oxide and propylene oxide, preferably in the form of a mixture thereof, such as the material marketed as Plurafac A-24, or in the form of certain ethoxylated secondary alcohols, particularly the biodegradable nonionic surfactants comprised of ethoxylates of a mixture of secondary alcohols having linear alkyl chains of from 11 to 15 carbon atoms, such as Tergitol 15-S-5 or Tergitol 15-S-9, the variations in sensitivity being provided by the addition to the above

Abstract: Biodegradable water washable dye penetrant composition in the form of a gel for use in non-destructive dye penetrant inspection of parts, and which can be applied to part surfaces at varying angles without dripping, and being resistant to decomposition and liquefaction when applied to heated surfaces, e.g. up to about 300.degree.

Abstract: Surface defects in composite and adhesively bonded structures that penetrate to a metal substrate are detected by applying a solution of 8-hydroxyquinoline to a surface of such a structure and viewing the surface under ultraviolet light. The presence of a flaw or crack leading from the surface to the metal substrate is indicated by a fluorescent glow.

Abstract: Water washable substantially biodegradable dye penetrant composition for use in non-destructive dye penetrant inspection of parts for locating cracks and flaws therein, consisting essentially of an organic dye, preferably a fluorescent dye, a carrier or solvent for said dye in the form of certain ethoxylated linear alcohols, particularly the biodegradable nonionic surfactants comprised of ethoxylates of a mixture of secondary alcohols having linear alkyl chains of from 11 to 15 carbon atoms, and an average of from 3 to 12 moles of ethylene oxide, and glycol monobutyl ether for thinning the dye penetrant solution substantially without affecting the sensitivity of the penetrant or its biodegradability, and facilitating application of the liquid dye penetrant composition by spraying to the surface of an object or part to be inspected.

Abstract: Liquid oxygen-compatible water washable substantially biodegradable dye penetrant composition having excellent sensitivity and high stability, for use in non-destructive dye penetrant inspection particularly of parts or mechanical components which are later placed in contact with liquid oxygen, and which are compatible with a wide variety of metals including steel alloys, such composition consisting essentially of an organic dye, preferably a fluorescent dye, a carrier or solvent for said dye, in the form of certain oxyalkylated alcohols, preferably ethoxylated linear alcohols,particularly the biodegradable nonionic surfactants comprised of ethoxylates of a mixture of secondary alcohols having linear alkyl chains of from 11 to 15 carbon atoms, and an average of from 3 to 12 moles of ethylene oxide, and a nonhalogenated solvent which is volatile at room temperature, e.g. a ketone such as methyl ethyl ketone or acetone, or a suitable alcohol such as ethyl alcohol.

Abstract: An improved method for the fluorometric measurement of a fluorescent label on a solid support surface in which the surface is read while coated with a continuous aqueous layer. For reading in a horizontal position, the surface is coated by immersion into a contained aqueous solution, and removed and read prior to evaporation to discontinuity. For reading in a vertical position, a layer of humectant is deposited on the surface to retain the water content.