Abstract: This invention provides a method and a test area to prevent tampering in the collection of specimens for substance abuse testing from a subject utilizing a specimen collection container. More particularly, the present invention prevents the substitution of the subject by another person and prevents the subject from introducing a previously obtained and concealed false specimen while minimizing intrusion on the subject's privacy.

Abstract: An article such as a drawn optical fiber (21) or an array of optical fibers is provided with a curable coating material. The array of optical fibers may be held together with a curable matrix material (45). Included in the coating material or the matrix material is a fluorescent constituent the fluorescence emission of which changes as a function of the degree of cure of the coating or matrix material. After the in-line curing of the coating material or of the matrix material, the fluorescence emission of the fluorescent constituent is monitored to determine the degree of cure of the curable material.

Abstract: Analyzing the level of a treating agent and/or stress metals in a body of water containing an inert transition metal tracer added to the water proportionally with the treating agent by determining the absorbance (first absorbance value) of a reagent dye added to water, said dye producing a second absorbance value when reacted at the same concentration with the tracer and stress metals in a measure of said body of water, and said dye producing a third absorbance value when reacted at the same concentration with only the transition metal contained in a measure of said body of water; determining the second and third absorbance values and resolving their differences to determine the concentration of the tracer and, separately, the concentration of said stress metals.

Abstract: A method for quantifying transcytosis through the blood-brain barier by infusing a perfusate into the brain of a living mammal. The perfusate includes a radio-labelled test compound and a radio-labelled marker compound. The perfused brain is removed from the animal and homogenized. The homogenized brain is separated into a microvasculature fraction and a supernatant fraction. The net volume of distribution of the test compound in the supernatant is calculated and corrected to provide an accurate measure of transcytosis through the blood brain barrier.

Abstract: A method and kit for determination of subsets of leukocytes utilizing flow cytometry analysis techniques.

Abstract: A solid meal gastric emptying kit comprising:(a) a first relatively small tagging container;(b) a first package of freeze-dried meat for tagging with TC.sup.99m Sulfur Colloid;(c) a second relatively large mixing and serving container;(d) a second package containing a napkin, a towelette, and a plastic spoon;(e) an absorbant pad;(f) radioactive material labels; and(g) instructions for preparation.

Abstract: A blood sample is prepared by combining a fluorescently tagged monoclonal antibody with blood cells. The sample is then passed through a flow cytometer and light scattered by each blood cell in two directions is sensed simultaneously by a single sensor. Lymphocytes are discriminated from other cells by using an intensity distribution of the total scattered light. Then, by using a distribution of fluorescent light intensity of each cell thus discriminated, the cells in a lymphocyte subclass of interest are enumerated with a high accuracy. The data acquired are utilized in diagnosing immunological incompetence or the like.

Abstract: A reagent for reticulocyte counting by flow cytometry which comprises two solutions, namely, a stock solution for staining in which a dye is dissolved in a nonaqueous solvent, and a buffer solution which satisfies the optimum staining conditions.By combining these two solutions immediately before measurement, a stable final staining solution for reticulocyte counting can always be obtained.

Abstract: A dosage system for administering drugs and conducting gastric flow studies is configured in the form of a multiplicity of substantially spherical subunits which have advantageously preselected particle diameter and density to customize the flow rate of the subunits with respect to the rate of flow of at least certain portions of the chyme. The diameter and density are related to one another in accordance with a relationship: ##EQU1## where N.sub.V is a dimensionless group having a predetermined value representing gastric residence time, g is the gravitational constant, .DELTA.p is the difference in density between the subunits and the chyme, and <v> is the linear velocity of the chyme. The flow rate of the subunits can be made slower, faster, or substantially equal to that of the chyme, as required to treat certain disease states. Also, the subunits can be provided with an enteric coating which permits more precise administration of certain drugs, such as those used in enzyme supplementation therapy.

Abstract: A reagent for reticulocyte counting by flow cytometry characterized in that it contains a carbonate salt.If a blood sample is left exposed to ordinary air, non-specific staining of erythrocyte can be prevented with the addition of not less than about 1 mM of NaHCO.sub.3.

Abstract: A method of determining the amount of nutriment absorbed in living organisms comprising animals, fish and plants comprises adding to the animal, fish or plant food one or more elements from the lanthanide series as tracers. After the nutriment has been absorbed, a sample is taken from a localized part of the living organism, for example a fish scale, and the sample is analyzed by ICP (inductively coupled plasma) to determine the amount of tracer and thus the amount of absorbed nutriment in the living organism.

Abstract: Methods for utilizing transition metals as tracers in aqueous liquid systems are provided by this invention. Transition metals with low background levels in system waters are identified as preferred when soluble in said aqueous liquid systems. The transition metals show low levels of deposition on equipment scale and provide reliable information as to the process history of the liquid systems.

Abstract: A radioactive assay method for measuring the humectant properties of cosmetic or non-cosmetic formulations or substances of any consistency, e.g. biological or synthetic liquids, solids, solutions, suspensions, isolated stratum coreum and hair, by measuring the uptake of radioactive water vapor.

Abstract: Nucleotides conjugated with a chelating agent and labeled with a lanthanide, especially terbium, are readily detected by time-resolved fluorimetry during and following gel electrophoresis. The labeled nucleotide conjugates are very stable, highly fluorescent with a long radiative lifetime and remain fluorescent during dilution and during gel electrophoresis and since an enhancement solution is not required for detection, the labeled nucleotide conjugates can be detected on-line, if desired.

Abstract: The invention includes a method of, and substances for use in the method of, identifying the source of a urine sample to be collected for biochemical analysis including administering to a person or animal whose urine is to be tested a formulation containing predetermined portions of one or more identifying substances that are vitamins, maintaining an identification of the formulations so that the person or animal to which it was administered and a urine collecting means can be identified, obtaining a urine sample from the person or animal in the urine collecting means, and analyzing the urine sample for the presence of the identifying substances or their metabolites.

Abstract: A process for determining the degree of saturation of a solution comprising a solvent and a compound of limited solubility which involves the steps of (1) diluting a feed solution of the compound of limited solubility, (2) passing a sample of the diluted feed solution through a bed of a solid solution of the compound and a tracer in which the tracer is intrinsically incorporated into the crystal structure of the compound, so that the diluted feed solution being tested becomes saturated with the compound by dissolution of a portion of the solid solution in the bed, (3) measuring the concentration of the tracer in the sample after passage through the bed of solid solution, thus measuring the amount of the compound dissolved from the solid solution to saturate the diluted feed solution, and (4) determining the degree of saturation of the compound in the feed solution from the measured values

Abstract: A method for analyzing marker dye present in the parts per million range in gasoline is provided using a solid-phase extraction technique with formation of the colored complex in the extraction column as well as a method for detecting the adulteration of gasoline containing the marker.

Abstract: A process for determining the degree of saturation of a solution comprising a solvent and a compound of limited solubility which involves the steps of (1) diluting a feed solution of the compound of limited solubility, (2) passing a sample of the diluted feed solution through a bed of a solid solution of the compound and a tracer in which the tracer is intrinsically incorporated into the crystal structure of the compound, so that the diluted feed solution being tested becomes saturated with the compound by dissolution of a portion of the solid solution in the bed, (3) measuring the concentration of the tracer in the sample after passage through the bed of solid solution, thus measuring the amount of the compound dissolved from the solid solution to saturate the diluted feed solution, and (4) determining the degree of saturation of the compound in the feed solution from the measured values.

Abstract: A method for determining the extent of polymerization of a polymer system consisting of adding a fluorescent label, the label having a reactivity similar to the reactivity of the curing agent, to the polymer system and measuring the fluorescence intensity proportional to cure species concentration during polymerization. The fluorescence intensity of the label exhibits sensitive changes throughout the polymerization process, allowing one to follow cure reactions in a quantitive way by measuring fluorescence, especially in the latter stages of cure. The cure species composition, reactivity ratio, activation energy and weight-average molecular weight can also be determined by adding a label and measuring the UV-VIS spectra in addition to the fluorescence intensity.

Abstract: This disclosure relates to a method and reagents for determining amphetamine and methamphetamine in a biological fluid such as urine. In particular, this disclosure relates to a fluorescence polarization immunoassay procedure for determining the presence of amphetamine and methamphetamine in a single assay and to a novel class of tracer compounds employed as reagents in such procedures. The procedure described includes pretreatment of the biological sample to eliminate cross-reactants such as .beta.-hydroxyphenethylamine by preincubating the sample solely with an aqueous periodate solution having a pH from about 4.0 to about 7.5 without adjustment to an alkaline pH.

Abstract: The present invention provides a method for measuring the activity of thioredoxin reductase in mammalian cells by contacting the cells in vivo or in vitro with a quaternary ammonium salt spin-labelled with a stable nitroxide free radical, and measuring the rate of reduction of the uncomplexed nitroxide free radical at the cell surface by electron spin resonance. This rate of reduction provides a measure of thioredoxin reductase activity at the surface of the cells.

Abstract: A method of preparing a sulfonamide-food color additive for detecting the presence of a compound such as a sulfonamide in animal feeds and pharmaceutical preparations for human or veterinary use involves admixing a minor amount of an approved food color additive with the compound in the presence of water and drying the resulting mixture to the desired form so as to incorporate the food color additive into the water of crystallization or other molecular structure of the compound. Upon being wetted, the resulting compound-food color additive produces a readily detectable color indicative of the presence of the compound. The method is particularly useful for detecting unacceptable levels of sulfonamides in animal feeds.

Abstract: A variety of methods and apparatus for the detection of an analyte of interest in a fluid sample is provided which relies upon the interaction of a fluorophore and a chromophoric light absorbing compound for qualitative and quantitative results. The methods preferably employ fiber optic sensors in combination with fluorophores and/or proto-absorber substances in mobile and immobilized modes of use. The methods and apparatus rely upon the ability of the light absorbing compositions to absorb energy which is transferred either radiatively or non-radiatively by the fluorophore when in an excited state.

Abstract: A method is provided for simultaneously measuring total cellular DNA and incorporated nucleoside analog. The method entails altering the cellular DNA of cells grown in the presence of a nucleoside analog so that single stranded and double stranded portions are present. Separate stains are used against the two portions. An immunochemical stain is used against the single stranded portion to provide a measure of incorporated nucleoside analog, and a double strand DNA-specific stain is used against the double stranded portion to simultaneously provide a measure of total cellular DNA.The method permits rapid flow cytometric analysis of cell populations, rapid identification of cycling and noncycling subpopulations, and determination of the efficacy of S phase cytotoxic anticancer agents.

Abstract: A method for assay of an analyte and assay device therefor. The assay device includes an assay component affixed to a permeable membrane. The membrane preferably rests on a permeable membrane support and covers an opening through a receptacle for holding a liquid. The support is adjacent the open upper end of a double ended needle, the lower end of which is adapted to puncture a plug inserted in an open end of a preevacuated container. Puncturing of the plug establishes fluid communication between the prevacuated interior of the container and the opening in the receptacle whereby liquid in the receptacle is passed through the membrane. The membrane has a bubble point sufficient to prevent passage of air through the membrane after all of the liquid has been pulled through as long as the membrane remains wet so that vacuum in the tube is not lost. The device may be part of an assay workstation which comprises a canister and various utensils useful in performing the assay.

Abstract: Compound having the following structure: ##STR1## R is a direct chain or branched alkylene group comprising 2-8 carbon atoms,n and m are 0 or 1,Y is a carboxylic or phosphonic acid, andX is an active functional group which permits covalent coupling to a bio-organic molecule.

Abstract: An analysis system includes a sample inlet, a diluent inlet, and a mixing chamber that has an outlet through which a mixture of the sample and diluent is flowed and in which a mechanical mixing member is housed. Positive displacement pumps preferably concurrently flow diluent to the mixing chamber and draw diluted sample to be analyzed from the mixing chamber. Bubble separation apparatus has a first branch connected to a drain and a second branch connected to the analyzer input. In a particular embodiment, the analyzer apparatus includes a nebulizer that controls the flow rate of the bubble-free stream through the second branch, sample excitation apparatus in the form of an induction coupled plasma (ICP) torch for exciting the sample to spectroemissive levels, and means for spectroanalysis of the excited sample at the output of the torch.

Abstract: A method for the simultaneous flow cytometric measurement of the total DNA content and the level of DNA synthesis in normal and malignant cells is disclosed. The sensitivity of the method allows a study of cell cycle traverse rates for large scale cell populations as well as single cell measurements. A DNA stain such as propidium iodide or Hoechst 33258 is used as the probe for the measurement of total DNA content and a monoclonal antibody reactive with a DNA precursor such as halodeoxy-uridine (HdU), more specifically bromodeoxyuridine (BrdU) is used as a probe for the measurement of HdU or BrdU uptake by the cells as a measure of DNA synthesis.

Abstract: Tagging compounds (which function as both dyes and markers) having the following structures: ##STR1## wherein x is an integer between 0 and 3 inclusive, y is an integer between 1 and 3 inclusive, z is 0 or 1, and R is a straight or branched chain hydrocarbon having from 1 to 5 carbon atoms are disclosed. These compounds can be dissolved in a diluent at a concentration of from about 10 percent to about 30 percent, forming a concentrate which can be further dispersed in an organic liquid to form a final concentration of from about 1 ppm to about 15 ppm of said tagging compound in said liquid. Methods for detecting the presence of a tagged compound in an organic liquid are also disclosed.

Abstract: A method for tagging an oil so that subsequently it may be identified as to source by incorporating into the oil as a tracer material an oil-soluble or oil-dispersible Group VIB, Group VIIB or lanthanum series rare earth metal salt of a fatty acid. The so-tagged oil may be utilized in any desired manner. Thereafter, an oil suspected to contain at least a portion of the so-tagged oil is analyzed for the presence of the added metal moiety. The method is especially useful in tracing a complex oleaginous and petroliferous material so that it may be recovered and identified following a theft or spill or to trace the flow of such oil injected through a subterranean reservoir.

Abstract: A method and apparatus for the rapid detection and pinpoint location of leaks in one or more of a plurality of subsurface fluid storage tanks. A quantity of tracer material such as a fluorinated halocarbon compound is mixed with fluids in each of the plurality of underground storage tanks. A first subsurface vapor pipe or conduit having an above-surface air inlet and a plurality of apertures therein is positioned in the backfill within the vicinity of the tanks and the above-surface inlet is used for conducting, drawing or sucking air into the air inlet pipe. A second subsurface sample or collection pipe having an above-surface pipe outlet and a plurality of apertures therein is also positioned in the vicinity of the tanks into the backfill. Air drawn down into the vapor pipe passes through the backfill and past a plurality of storage tanks and in close proximity thereto, and into the sample pipe. Any tracer which is leaking from the tank or tanks will be picked up and drawn into the sample pipe.

Abstract: A method for determining the extent of polymerization of an epoxy system consisting of adding a fluorescent label, the label having a reactivity similar to the reactivity of the curing agent, to the epoxy system and measuring the fluorescence intensity during polymerization. The fluorescence intensity of the label at its emission maximum increases sharply with polymerization, allowing one to follow cure reactions in a quantitative way by measuring fluorescence, especially in the later stages of cure beyond gelation. The composition, reactivity ratio, activation energy and weight-average molecular weight can also be determined by adding a label, such as p,p'-diaminoazobenzene (DAA) or trans diamine-stilbene (DAS), to mimic the reactivity of the curing agent, such as diaminodiphenyl sulfone (DDS) or methylene dianiline (MDA), and measuring the UV-VIS spectra in addition to the fluorescence intensity.

Abstract: An apparatus and method for detecting leaks from underground gasoline storage tanks and the like by routine or periodic soil samples tested for a particular tracer. A fluorinated halocarbon compound tracer having a boiling point less than that of gasoline is slowly dispensed within the gasoline, natural gas, or the like in the tank. A sampling pipe having a plurality of apertures therein is also buried in selected locations in the vicinity of the tank, and samples of the soil gas are pumped from the pipe and supplied to a Nafion water separator prior to analysis by gas chromatographic techniques. If a leak in the tank should occur, the tracer will exit with the leaking gasoline, quickly vaporize, and travel rapidly by molecular diffusion in all directions. Elements of the tracer will therefore be detected in the soil gas pumped from the sample pipe using standard gas chromatography techniques, indicating that a leak exists in the tank.

Abstract: A method for measuring hematocrit is provided. An electrochemically detectable marker is measured before and after the ratio of red cell volume to plasma volume is decreased. The measured concentrations are used in a mathematical formula to determine hematocrit value.

Abstract: The invention provides a method for tagging methane by adding thereto one or more of the tracer compounds sulfur hexafluoride and chloropentafluoroethane. The methane being tagged is normally being stored in underground storage fields to provide identity and proof of ownership of the gas. The two tracer compounds are readily detectable at very low concentrations by electron capture gas chromatography apparatus which can be made portable and thus suitable for use in the field.

Abstract: Pancreatic exocrine function is determined by a breath test method wherein a radioactive labelled ester such as cholesterol octanoate is ingested in the body and is hydrolyzed by pancreatic enzymes and oxidized to labelled Co.sub.2 which is expired in the breath. The rate of appearance of labelled Co.sub.2 in the breadth is a function of the rate of hydrolysis by pancreatic enzymes which in turn reflects pancreatic exocrine function. Before ingestion, the ester is mixed with a carrier substrate such as a triglyceride to form a lipid matrix containing the ester and the lipid matrix is suspended in aqueous solution. To insure that low levels of expired labelled Co.sub.2 is due to pancreatic exocrine insufficiency, the ester is ingested simultaneously with a differentially labelled unesterfied carboxylic acid or the test method is repeated with an added step of simultaneously ingesting the ester with exogenously provided pancreatic enzymes.

Abstract: A fluorescently labeled complex hydrophobic fluid produced by dissolving a porphyrin therein. The porphyrin must be substantially soluble in acidic aqueous solutions, substantially insoluble in neutral or alkaline aqueous solutions and fluoresce at a wavelength between about 600 nm and 800 nm when irradiated at a wavelength between about 350 nm and 550 nm. The fluorescently labeled complex hydrophobic fluid may be identified by observation of the above-mentioned characteristic fluorescence upon irradiation. For identification purposes the porphyrin may be first extracted into an acidic aqueous solution for determination of fluorescence. In cases where the labeled hydrophobic fluid has been dispersed in a quantity of neutral or alkaline aqueous solution or suspension, this latter solution or suspension is first extracted with a hydrophobic solvent for the porphyrin to form a porphyrin solution. The prophyrin, in turn is extracted from this prophyrin solution with an acidic aqueous solution.

Abstract: A tracer particle for determining the concentration of a microingredient in a bulk material is disclosed. The tracer particle comprises a finely divided ferromagnetic particulate material approximately 90% of which is approximately 325 mesh or smaller, a microingredient and a binder wherein the microingredient and ferromagnetic material are entrapped in the binder and wherein the tracer particle is approximately 35 to 80 mesh in size.

Abstract: 9-Azido-6-halo-3-lower alkyl-2,3,4,5-tetrahydro-1H-3-benzazepines are prepared from their 9-amino congeners. The compounds are useful as photoaffinity probes for .alpha..sub.2 -adrenoceptor sites in biological samples.

Abstract: An information carrier for recording information concerning a product. The carrier is formed of a fluoroplastic and is adapted to be affixed to the product. It includes a first side for facing a component of the product and a second side remote from the first side. The strip also includes an interior portion disposed between the sides with the interior portion having a color sharply contrasting with that of the second side. Thus, discrete bar-like segments of the second surface can be removed to expose the sharply contrasting color of the interior portion to provide coded information about the product. The carrier is formed of a severe environment resistant fluoroplastic so that it can travel with the component through severe environment processing steps.

Abstract: A method of chemical analysis is disclosed which employs a release tag compound of general formulaRx--Re--Sin which Rx is a reactivity group capable of forming a covalent bond with another molecule, Re is a release group capable of being cleaved, and S is a signal group. The release tag is covalently bonded to a substance of interest which is to be determined in the course of a chemical analysis for an analyte, release group Re is cleaved at an appropriate point in the analytical procedure, and signal group S is determined, thereby determining the substance of interest. Where the substance of interest is the analyte, determination of S determines the analyte. Where the substance of interest is not the analyte but is related to the analyte concentration, determination of S allows indirect determination of analyte.

Abstract: A process and apparatus has been developed for radioassay of ligand in solution which eliminates the separation step required in conventional techniques. A chamber is provided containing a quenching solution, a plurality of ligand molecules and a plurality of receptor molecules. One of pluralities forms a free species labelled with a beta particle emitter while the other is immobilized on a solid support, e.g., the chamber wall or a microbead, within the chamber. Ligand introduced with the sample competes with ligand molecules already in the chamber for receptor sites on the receptor molecules and the free species is allowed to diffuse about the chamber. A beta particle detector in communication with the chamber at a fixed position detects only those beta particles emitted from within the quenching distance of the quenching solution. The quenching properties of the solution are used in place of the conventional separation step.

Abstract: A safe and inexpensive method of measuring blood flow in experimental animals using non-radioactively labeled microspheres is provided. The microspheres may be comprised of a variety of materials, including latex and agarose, and may be labeled with colored dyes or by linkage to enzymes, plant enzymes being preferred because they do not occur naturally in an animal's system. After injection and circulation of the microspheres throughout the animal's system, blood flow to particular tissue may be measured by counting the number of microspheres in the tissue sample, the initial number of microspheres in the animal's blood stream having been measured shortly after injection. In the case of microspheres labeled with colored dyes, the spheres may be counted in tissue either after separation from the tissue or while still trapped in the tissue's capillaries. Techniques for separating the microspheres from blood and tissue are also provided.

Abstract: A method of determining source areas of pollution aerosol. Selected pollution derived, fine particle tracer elements from within the source region are measured. The measured results are expressed as ratios to one of the tracer elements. A signature of the source region is determined from modes in the logarithmic frequency of the ratios of the tracer elements. Measurements are made of the tracer elements from a receptor region and elemental ratios constructed. The elemental ratios from the receptor region are compared with the signatures from possible source regions to determine the most probable source region.

Abstract: A tracer composition is described whereby a nonradioactive photon emitter is coupled to a ligand, antigen or antibody for use in various immunoassay methods of analysis. The photon emitters employed are bioluminescent proteins such as firefly or bacterial luciferase as well as other luciferases from various species. To synthesize the new tracer, these photon emitters are coupled to antigens or antibodies using coupling agents such as glutaraldehyde, CNBr, carbodiimide and others. The coupling method may also include intermediate materials such as polysaccharides, polypeptides, polyacrylamides and others coupled between the photon emitter and the antigen or antibody.Methods are described for using this tracer in both competitive and noncompetitive immunoassays to detect proteins, hormones, drugs, viruses and the like. Detection is accomplished by activating the tracer in a bioluminescent reaction and measuring the emitted light by photometric instruments or by photographic film.

Abstract: The method for determining flow patterns within a subterranean formation penetrated by a spaced apart injection system and production system that comprises injecting into the formation at a predetermined depth from the injection system a solution containing a small amount of one or more water-soluble tracer compounds, recovering said tracer in the production system, determining the depth of recovery, and identifying said tracer compounds by gas chromatography and flame ionization detector; said tracer compounds being water-soluble organic compounds having phosphorus, nitrogen, or sulfur in the molecule.

Abstract: The method for determining flow patterns within a subterranean formation penetrated by a spaced apart injection system and production system that comprises injecting into the formation at a predetermined depth from the injection system a solution containing a small amount of one or more water-soluble tracer compounds, recovering said tracer in the production system, determining the depth of recovery, and identifying said tracer compounds by gas chromatography and flame ionization detector; said tracer compounds being water-soluble organic compounds having phosphorus, nitrogen, or sulfur in the molecule.

Abstract: A method of tracing sewage effluent is described in which samples of fluid flows are subjected to high performance liquid chromatography with respective elution systems capable of eluting different selected compounds therefrom, and the concentration of each compound in the sample is determined spectroscopically. The method is used to determine sewage flow paths in natural water bodies, such as rivers, to check for contamination by sewage, to determine possible sewage sources, the detection of uric acid, for example, being indicative of a human source; and to monitor the effluent from sewage treatment plants.

Abstract: The invention provides a method for tagging methane by adding thereto one or more of the tracer compounds sulfur hexafluoride and chloropentafluoroethane. The methane being tagged is noramlly being stored in underground storage fields to provide identity and proof of ownership of the gas. The two tracer compounds are readily detectable at very low concentrations by electron capture gas chromatography apparatus which can be made portable and thus suitable for use in the field.

Abstract: An identification technique for micro-organisms in which a dilute solution of a culture medium containing an unknown micro-organism has added thereto an emissive agent such as a radioactive amino acid to produce a mix of emissive products that depends on the metabolic mechanism of the micro-organism. After a predetermined incubation period, the reaction is arrested and the solution layered onto a gel plate where it is subjected to electrophoresis. The plate is then autoradiographed by exposing the gel to a sensitive photographic film for a period sufficient to produce thereon a characteristic band pattern functioning as an identifier for the micro-organism. Identification may be effected by comparing the identifier for the unknown with a collection of identifiers for known micro-organisms to find a match with one of these known identifiers.