Abstract: An improved assay for detecting an analyte in a fluid sample includes a step of conducting a photochemical reaction, in which a substrate conversion catalyzed by a photosensitizer into a product of the photochemical reaction is temporary inhibited when the reaction mixture is irradiated with a light at a wavelength within a light absorption spectrum of the photosensitizer. The photosensitizer (or an enzyme to catalyze producing thereof) is attached to an entity having an affinity to the analyte, such entity is bound to the analyte prior to irradiation. To achieve temporary inhibition, certain additives are used such as ascorbic acid or its derivatives. The assay may increase the sensitivity of ELISA 20- to 100-fold.

Abstract: An improved assay for detecting an analyte in a fluid sample includes a step of conducting a photochemical reaction, in which a substrate conversion catalyzed by a photosensitizer into a product of the photochemical reaction is temporary inhibited when the reaction mixture is irradiated with a light at a wavelength within a light absorption spectrum of the photosensitizer. The photosensitizer (or an enzyme to catalyze producing thereof) is attached to an entity having an affinity to the analyte, such entity is bound to the analyte prior to irradiation. The assay may increase the sensitivity of ELISA 20- to 100-fold.

Abstract: Provided are a method for detecting biomaterials, a method for fabricating a chip for biomaterial detection and a chip for biomaterial detection. The method for detecting biomaterials is characterized by comprising the steps of: (S1) immobilizing polydiacetylene liposomes onto a substrate; (S2) linking the polydiacetylene liposomes together and layering them on the substrate; (S3) immobilizing a material which forms a complementary binding with a subject biomaterial to be detected onto the polydiacetylene liposomes; (S4) exposing the resulted polydiacetylene liposome to UV light so as to form a chip for biomaterial detection; (S5) applying the subject biomaterial to be detected to the chip for biomaterial detection for reaction; and (S6) measuring a fluorescent signal from the chip for biomaterial detection.

Abstract: A photoelectrochemical assay apparatus and method for determining chemical oxygen demand (COD) of a water sample is described. The photoelectrochemical assay comprises: a) a measuring cell for holding a sample to be analysed b) a titanium dioxide nanoparticle photoelectric working electrode and a counter electrode disposed in said cell, c) a UV light source adapted to illuminate the photoelectric working electrode d) control means to control the illumination of the working electrode e) potential measuring means to measure the electrical potential at the working and counter electrodes f) analysis means to derive a measure of oxygen demand from the measurements made by the potential measuring means.

Abstract: An oxygen sensitive probe comprises a monofunctional derivative of an oxygen-sensitive photoluminescent dye covalently attached to a water soluble and/or hydrophilic macromolecular carrier. The probe may be a chemical conjugate of a monofunctional phosphorescent porphyrin dye and a poly(ethyleneglycol), polypeptide or polysaccharide.

Abstract: A method for silver staining a gel on which biological substances such as nucleic acids and proteins are separated by electrophoresis, which comprises at least the following steps: (a) the step of immersing an untreated gel after the electrophoresis in an aqueous solution of sodium thiosulfate; (b) the step of immersing the gel obtained in the step (a) in a mixture of ethanol and an aqueous solution of sodium acetate; and (c) the step of immersing the gel obtained in the step (b) in a mixture of ethanol and an aqueous solution of silver nitrate.

Abstract: A photoelectrochemical assay apparatus for determining chemical oxygen demand (COD) of a water sample which consists of a) a measuring cell for holding a sample to be analysed b) a titanium dioxide nanoparticle photoelectric working electrode and a counter electrode disposed in said cell, c) a UV light source adapted to illuminate the photoelectric working electrode d) control means to control the illumination of the working electrode e) potential measuring means to measure the electrical potential at the working and counter electrodes f) analysis means to derive a measure of oxygen demand from the measurements made by the potential measuring means.

Abstract: A self-calibrated, magnetic binding assay (e.g., sandwich, competitive, etc.) for detecting the presence or quantity of an analyte residing in a test sample is provided. The magnetic binding assay includes detection probes capable of generating a detection signal (e.g., fluorescent non-magnetic particles) and calibration probes capable of generating calibration signal (e.g., fluorescent magnetic particles). The amount of the analyte within the test sample is proportional to the intensity of the detection signal calibrated by the intensity of the calibration signal.

Abstract: We disclose methods of sorting or separating mixtures of living cells (e.g., eukaryotic, prokaryotic, mammalian, pathogenic, bacterial, viral, etc.). We perform our methods by activating cell-selective photophoric labels, which photosensitize and chemically reduce a photosensitive metal compound to form metal grains, particles or crystals. The metal adheres to the cells and forms the basis for sorting or separating different cell types. Photophoric labels may include chemiluminescent agents such as peroxidase enzymes activated with peroxidase substrates capable of luminescence. Photosensitive metal compounds may be present in a light-sensitive matrix or emulsion containing photosensitizable metal compounds, which form metal grains, particles or crystals upon exposure to a developer solution. Developer solutions are formulated to substantially allow living cells to remain viable after exposure to the developing solution.

Abstract: The invention provides methods and compositions for azide tagging of biomolecules. In one embodiment of the invention, proteins are tagged by metabolic incorporation of prenylated azido-analog substrates. Examples of such analogs are azido farnesyl diphosphate and azido farnesyl alcohol. The azido moiety in the resulting modified proteins provides an affinity tag, which can be chemoselectively captured by an azide-specific conjugation reaction, such as the Staudinger reaction, using a phosphine capture reagent. When the capture agent is biotinylated, the resulting conjugates can be detected and affinity-purified by streptavidin-linked- HRP and streptavidin-conjugated agarose beads, respectively. The invention allows detection and isolation of proteins with high yield, high specificity, and low contamination without harsh treatment of proteins.

Abstract: The invention relates to a method for monitoring interactions to a target biomolecule comprising the steps of: providing a biomolecule of interest having specificity for the target biomolecule; binding the biomolecule of interest to at least one type of linker molecule comprising a unique mass marker part; introducing the biomolecule of interest to a cell; binding the linker to the target biomolecule; cleaving the linker molecule, thereby leaving the photoactivatable part and the mass marker part bound to the target; analysing the target biomolecule, thereby detecting the unique mass marker part. The detection can be carried out by MS in a parent ion scanning mode, thereby allowing study of the interaction between the biomolecule of interest and the target biomolecule.

Abstract: Nitroaromatic compounds and immunogenic conjugates comprising a novel nitroaromatic compound and a carrier protein are disclosed. The invention further presents monoclonal antibodies highly specific for the claimed nitroaromatic compounds, the compounds' protein conjugates, the compounds' reductive byproducts, and adducts formed between the compounds and mammalian hypoxic cell tissue proteins. The invention is further directed to methods for detecting tissue hypoxia using immunohistological techniques, non-invasive nuclear medicinal methods, or nuclear magnetic resonance. Diagnostic kits useful in practicing the methods of claimed invention are also provided.

Abstract: The present application describes novel uses of ruthenium bipyridyls or palladium porphyrins as photo-activatable crosslinking agents. Crosslinking can be between any two molecules including peptides, proteins, or compounds. Crosslinking occurs in the presence of an electron donor such as ammonium persulfate, and requires only moderate intensity visible light. Crosslinking can be between peptides, polypeptides or lead candidate compounds to unknown target molecules. Reagents utilyzing ruthenium bipyridyls and palladium porphyrins crosslinkers for use in diagnostic and detection scenarios are also disclosed.

Abstract: An efficient, lightweight, and relatively inexpensive photolysis system based on a short-arc Hg arc lamp provides a simple and accurate method for measurement of ambient NO2. High time resolution is achieved by minimizing inlet and photolysis cell residence times and matching NO and NO2 sample paths, and data reduction is greatly simplified relative to conventional photolysis designs.

Abstract: Disclosed is a colorimetric sensor comprising polydiacetylene membrane liposomes, a polydiacetylene membrane film or fine particles coated with a polydiacetylene membrane, in which the polydiacetylene membrane is incorporated with a protein having a reduced molecular weight low enough not to cause color change in the polydiacetylene membrane. The examples of the reduced-molecular-weight proteins include an antibody Fab′ fragment, an antigenic protein of molecular weight of 100,000 or less, and a peptide consisting of 3-20 amino acid residue, which undergo an antigen-antibody reaction with an antigen or antibody contained in a sample. As the reduced-molecular-weight protein is also employed a combination of single-stranded DNA of 100 bases or less which hybridizes with single-stranded DNA contained in a sample to form a double-stranded DNA, and an antibody which reacts with said double-stranded DNA but does not react with the single-stranded DNA contained in the sample.

Abstract: The invention relates to a method for determining the quality of a crop, comprising the determination of at least one characteristic parameter of the photosynthesis process of the crop, which parameter serves as a quality indicator for the crop, wherein the parameter belongs to the photosystem I (PSI), which is known per se, and wherein the determination of the parameter comprises the following steps: (a) bringing at least some of a number of types of molecules which are located on the donor side of PSI into an oxidised state; (b) allowing at least some of the oxidised molecules to be reduced; and (c) determining a relaxation parameter which contains information on the rate of the reduction, wherein step (c) comprises at least the following sub-steps: (1) measurement of absorption of light in a predetermined wavelength region by the oxidised molecules in the crop during the reduction, and (2) calculation of a rate parameter which contains information on the rate of a change in the measured absorption as a fun

Abstract: Systems and methods treat biological fluids carrying contaminants by photoactivating materials mixed with the fluids. The systems and methods quantify the photoreactions that occur in a manner that permits correlation with clinical results.

Abstract: A vessel holds a liquid content for exposure to prescribed light energy. The vessel has a region transparent to the prescribed light energy. The liquid content of the vessel includes a solution comprising a material undergoing reduction oxidation as a result of exposure to the prescribed light energy, and a reducing agent for the photoactive material. A device measures optical absorbance of the vessel and the liquid content. The device operates in a first instance to measure a first optical absorbance value before exposing the vessel and the liquid content to the prescribed light energy. The device also operates in a second instance to measure a second optical absorbance value after exposing the vessel and the liquid content to the prescribed light energy, to obtain a difference between the first and second optical absorbance values. The difference comprises an illumination characteristic for the vessel with respect to the prescribed light energy.

Abstract: Method and reagent composition for covalent attachment of target molecules, such as nucleic acids, onto the surface of a substrate. The reagent composition includes groups capable of attracting the target molecule as well as groups capable of covalently binding to the target molecule, once attracted. Optionally, the composition can contain photoreactive groups for use in attaching the reagent composition to the surface.

Abstract: This invention describes a method for the rapid identification of the presence of microorganisms in a sample. Briefly, in the method of this invention the sample container is divided into a plurality of discrete zones, each of which can be separately monitored for microbial presence. When a sample is placed into this container, detection is simplified as the volume monitored is low (as compared with the sample); since microbial detection is a concentration dependent phenomenon, the speed with which the presence of microbial contamination can be detected is increased.

Abstract: Methods for labeling a material are disclosed. The methods comprise combining with the material (a) a photosensitizer capable upon irradiation of generating singlet oxygen and (b) a chemiluminescent compound capable of being activated by singlet oxygen wherein the photosensitizer and the chemiluminescent compound are incorporated in a particulate matrix or a non-particulate solid matrix. The particulate matrix can be solid or fluid. The methods allow for generating delayed luminescence, which can be realized upon irradiation of the matrix. The methods have application to the determination of an analyte in a medium suspected of containing the analyte.

Abstract: Methods and compositions are provided for detecting nucleic acid sequences. In particular, pairs of probes are employed, where the pair defines a substantially contiguous sequence on a target nucleic acid. Each of the pairs has a side chain which forms a stem of the two side chains which non-covalently bind to is capable of forming a cross-link upon activation, when the probes and sample nucleic acid are base paired. Each of the nucleic acids is initially present as single stranded to allow for base pairing, so that the probes bind to homologous target nucleic acid. The assay mixture is activated to provide cross-linking, the double stranded nucleic acid melted, and the process of base pairing, activation and melting repeated, a sufficient number of cycles, to provide a detectable amount of cross-linked probes. Kits are provided with the appropriate reagents for carrying out the subject method.

Abstract: This invention relates to a new electrochemiluminescent (ECL) label for oligonucleotides using phosphoramidite chemistry.

Abstract: The present invention is directed to chromophoric probes for use in detecting nucleic acid sequences. More particularly, the invention is directed to probes that comprise a texaphyrin chromophore molecule covalently coupled or conjugated to a site-directing molecule, the site-directing molecule having affinity for a biological receptor or a nucleic acid sequence. In one embodiment of the invention, the probe comprises a texaphyrin chromophore conjugated to an oligonucleotide having complementary binding affinity for a target nucleic acid sequence.

Abstract: A family of benzochlorins, a family of verdins, a family of porphyrin derivatives and metal complexes thereof are disclosed. The benzochlorins have the formula of FIG. 3 of the attached drawings; their metal complexes have the formula of FIG. 1. The verdins have the formula of FIG. 4 of the attached drawings; their metal complexes have the formula of FIG. 2. The porphyrin derivatives have the formula of FIG. 7 of the attached drawings; their metal complexes have the formula of FIG. 8. Solutions of the benzochlorins, verdins, porphyrin derivatives and metal complexes which are physiologically acceptable for intravenous administration are also disclosed, as are emulsions or suspensions of the solutions, and compositions which additionally include cyclodextrin, and wherein the molecules of the benzochlorin, verdin, porphyrin derivative or metal complex are encapsulated within the molecules of the cyclodextrin. The solvent for the solutions can be a product of the reaction of ethylene oxide with castor oil.

Abstract: Specific binding assays are disclosed which utilize a sensitizer as a label. Such sensitizers include any moiety which, when stimulated by "excitation" with radiation of one or more wavelengths or other chemical or physical stimulus (e.g., electron transfer, electrolysis, electroluminescence or energy transfer), will achieve an excited state which (a) upon interaction with molecular oxygen will produce singlet molecular oxygen, or (b) upon interaction with a leucodye will assume a reduced form which can then be returned to its original unexcited state by interaction with molecular oxygen resulting in the production of hydrogen peroxide. Either interaction with the excited sensitizer will, with the addition of other reagents, produce a detectable signal.

Abstract: The content of decomposable organic carbon compounds present in a gaseous phase is determined down to the parts per billion (10.sup.-9) range and in special cases down to the parts per trillion (10.sup.-12) range. The gaseous sample material being tested is introduced into a limited quantity of water wherein the organic compounds are photolytically decomposed. The decomposition products are ascertained in the carrier gas and/or in the limited quantity of water.

Abstract: Irradiating, with ultraviolet light, surfaces which contain thiol groups, epoxy groups, or vicinal diol groups, results in surfaces which exhibit a reduced adsorption of biomolecules. In the case of surfaces having thiol groups such irradiation also results in a reduced capacity for the bonding of heterobifunctional crosslinking reagents. Such irradiation may be carried out in a patternwise fashion to obtain patterned surfaces.

Abstract: A chemical moiety is disclosed which comprises a chemical, biochemical, or biological substance attached to one or more electrochemiluminescent organometallic compounds. In a preferred embodiment of the invention the substance is attached to one or more ruthenium-containing or osmium-containing luminescent organometallic compounds. Methods are disclosed for detecting low concentrations of the chemical moiety using chemiluminescent, electrochemiluminescent, and photoluminescent means. Compounds are disclosed which are useful for labeling substances of interest with ruthenium-containing and osmium-containing labels or other electrochemiluminescent labels. These labeled substances are useful in methods provided for detecting and quantifying analytes of interest in binding assays and competitive binding assays. The labeled substances are of particular use in homogeneous binding assays.

Abstract: The present invention provides a process of quantifying the number of viable cells in an aqueous suspension of cells using an energy-emitting non-hazardous probe and a probe-trigger. The process provides quantification data in short periods of time without the use of hazardous materials. A process of the present invention can also be used to quantify negatively charged particle number, assay for cytotoxicity, assay for cell proliferation and assay for cell differentiation. Still further, the present invention provides an assay kit for quantification of cells or negatively charged particles.

Abstract: A polyacrylamide gel comprising acrylamide and diacrylylpiperazine. A method for providing a polyacrylamide gel comprising employing a catalyst system which comprises dimethylpiperazine, sodium thiosulfate or a mixture thereof and ammonium or potassium persulfate. The use of the gel as the matrix in a silver staining procedure for the detection of biomaterials, provides for the obtainment of reduced background staining.

Abstract: Apparatus and methods for measurement of total organic carbon content of water, particularly of low relative organic content, are described, featuring a single sample cell for exposure of a static sample to ultraviolet radiation and comprising electrodes for measuring the conductivity of the water. The conductivity is monitored as a function of time and the second time derivative of the conductivity signal is monitored to indicate when the oxidation reaction has been completed. Compensation for the contribution to conductivity of the water sample made by the instrument is achieved by subtracting a quantity proportional to the first time derivative of the conductivity at a time when the second time derivative reaches zero, indicating that the oxidation reaction is complete, from the change in the total conductivity measurement, the remainder being equal to the contribution to conductivity made by oxidation of the organic content of the water.

Abstract: A method and apparatus is provided for analyzing the leucocytes in a biological fluid. The biological fluid is passed through a filter material having a critical wetting surface tension greater than 53 dynes/cm so that the leucocytes are held in the filter by adsorption. The filter material is subsequently treated with luminogenic material so that the treated filter may be analyzed by luminescence detection.

Abstract: A method and system for determining organic matter in an aqueous solution including an oxidizing agent are disclosed. The method includes contacting the solution with a semiconductor which is capable of photocatalytically oxidizing the organic matter, illuminating the semiconductor with light of a wavelength or having a spectrum whereby the semiconductor photocatalytically oxidizes the organic matter in the solution to form a photocatalytic by-product(s), and detecting the by-product(s).

Abstract: Wet pressure sensitivity of a film having a silver halide coating is indirectly determined by measurement of a difference in density of a coating area which has increased pressure applied thereto compared to a coating area without such increased pressure.

Abstract: An improved silver staining technique is disclosd for the detection of a biocomponent contained in a support medium. The technique includes fixing the support medium with a fixing agent, pretreating the thus-fixed support medium with a sensitizer, treating the resultant support medium with a silver staining solution and then developing the thus-treated support medium with a reducing agent. In one aspect of the invention, thiourea is incorporated in either one or both of the fixing agent and sensitizer. In another aspect of the invention, thiosulfate is contained in the reducing agent. According to the invention, improved stainability and contrast are obtained. Also disclosed is a silver staining kit.

Abstract: A method and compositions including a 1,2-dioxetane and a fluorescent compound is described. In particular, enzymatic triggering of a triggerable 1,2-dioxetane admixed with a surfactant and the fluorescent compound attached to a hydrocarbon to provide a co-surfactant in a micelle or other structure providing close association of these molecules is described. The method and compositions are useful in immunoassays and in DNA probes used for various purposes.

Abstract: A method and apparatus are disclosed for the in vivo and in vitro detection and measurement of dose critical levels of DNA-binding anti-cancer drug levels in biological fluids. The apparatus comprises a laser based fiber optic sensor (optrode) which utilizes the secondary interactions between the drug and an intercalating fluorochrome bound to a probe DNA, which in turn is attached to the fiber tip at one end thereof. The other end of the optical fiber is attached to an illumination source, detector and recorder. The fluorescence intensity is measured as a function of the drug concentration and its binding constant to the probe DNA.Anticancer drugs which lend themselves to analysis by the use of the method and the optrode of the present invention include doxorubicin, daunorubicin, carminomycin, aclacinomycin, chlorambucil, cyclophosphamide, methotrexate, 5-uracil, arabinosyl cytosine, mitomycin, cis-platinum 11 diamine dichloride procarbazine, vinblastine vincristine and the like.

Abstract: A method for modifying the solid surface to improve its biocompatibility is disclosed. The method employs molecules of a biocompatible agent and a chemical linking moiety possessing a photochemically reactive group capable upon activation of covalently bonding to the solid surface and possessing a different reactive group as capable upon activation of covalently bonding to separate molecules of the biocompatible agent. The method comprises applying stimulus to sequentially activate the groups and covalently bind the different reactive group of the linking moiety to the molecules of the biocompatible agent and to photochemically covalently bind the linking moiety to the solid surface with a sufficient population density to enable the molecules of the biocompatible agent to effectively shield the solid surface and to provide a biocompatible surface.

Abstract: A method is provided for detecting the presence of organic materials in an aqueous sample. The materials are decomposed by simultaneous exposure to ultraviolet radiation and acoustic energy to decompose the materials to simple decomposition products. The simple decomposition products such as ammonium ion, halogen ion, alkyl ammonium ions, or sulfate ions, are then detected by conventional analytical devices and methods.

Abstract: A photoactivated time-temperature indicator is based on a leuco base system. A thermally insensitive, white ("inactive") leuco base (or a mixture of such leuco bases) is mixed, preferably in a polymeric matrix, with a material that generates acid upon exposure to light. Photoexcitation, preferably by UV or near UV light, causes the formation of a thermally sensitive, color-forming ("active") product. Following this activation step, a progressive color development occurs at a rate that increases with temperature. The indicator is useful for monitoring the freshness of perishable products, particularly those stored at subambient temperature.

Abstract: A system for measuring cyanides in a sample employs a photoillumination component for producing ultraviolet radiation to dissociate cyanides contained in an alkaline sample. The system includes filtering components interposed between the photoillumination components and an alkaline sample to be tested for passing lower frequency ultraviolet radiation to produce an irradiated sample in which cyanides have been dissociated, while blocking high frequency ultraviolet radiation to inhibit thiocyanate dissociation. Thin-film distillation components are included for separating cyanide from the irradiated sample to produce recovered cyanide for measurement purposes, and measuring components are provide for receiving the recovered cyanide generating a recordable signal indicative of recovered cyanide quantity.

Abstract: A polypeptide is located in a gel matrix by treating the matrix with a negative staining agent (i.e. an agent that stains the gel more intensely in regions devoid of polypeptides, so that gel areas exhibiting reduced staining intensity are indicative of the presence of polypeptide). Specifically, the staining agent comprises a copper or cobalt salt, and a detergent. The term polypeptide is used to include polypeptides of all sizes, including proteins and glycoproteins. The polypeptide can be purified by applying it to a gel matrix, causing it to run into the matrix, applying the above-described staining agent and then eluting the polypeptides from the matrix.

Abstract: A sample aqueous stream including one or more organic compounds capable of partial oxidation to acid form are flowed continuously through an ultraviolet light reactor in which the sample is exposed to ultraviolet light in the presence of oxygen under conditions to partially oxidize the organic compounds to convert at least a portion of them to their corresponding ionized organic acids. Thereafter, the sample stream continuously flows through a conductivity cell in which the changing conductivity of the sample is detected as an indication of the presence of organic compounds in the sample stream.

Abstract: A photoactivated time-temperature indicator is based on diacetylenic salts. A thermally unreactive ("inactive") diacetylenic salt (or a mixture of such salts) is mixed, in a polymeric matrix, with a material that generates acid upon exposure to light. Photoexcitation, preferably by UV or near UV light, causes the formation of a thermal reactive ("active") free diacetylenic acid. Following this activation step, a progressive color development occurs at a rate that increases with temperature. The indicator is useful for monitoring the freshness of perishable products, particularly those that require refrigeration.

Abstract: The present invention provides a carrier such as polyethylene having covalently bound to it a reaction component such as an antibody, for use for immune determinations. The reaction component is covalently bound via heterobifunctional photoactivatable compounds, one group of which is found by an aryl azide group. Protein A may be bound covalently to the carrier via heterobifunctional photoactivatable compounds, and antibodies bound to the protein A.

Abstract: A simple, positive image forming silver stain which takes less than 15 minutes to perform is disclosed for the detection of nanogram quantities of proteins and DNA on membranes and thin layer plates. This stain demonstrates a reproducible curvilinear relationship between silver density and the amount of protein or DNA, over an averaged concentration range from 1 nanogram to 300 nanograms for proteins and 10 nanograms to 700 nanograms for DNA. The ease of staining proteins and DNA on membranes, combined with the stain's sensitivity and reproducibility, permits quantitative determination and assay of proteins and DNA.

Abstract: Methods for attaching one component of a ligand-anti-ligand pair onto a solid phase surface. The component may be attached to a photoactivatable cross-linker capable of coupling the component to a colloidal medium coating the surface or alternatively, the component may be coupled to a bead and held in place against the surface by an overlay of the colloidal media having voids and spaces smaller than the diameter of the particle but large enough to permit diffusion of the other of the ligand-anti-ligand pair to be detected.

Abstract: Apparatus and methods for measurement of total organic carbon content of water, particularly of low relative organic content, are described which feature a single sample cell for exposure of a static sample to ultraviolet radiation comprising electrodes for measuring the conductivity of the water. The conductivity is monitored as a function of time and the second time derivative of the conductivity signal is monitored to indicate when the oxidation reaction has been completed. Compensation for the contribution to conductivity of the water sample made by the instrument is achieved by subtracting a quantity proportional to the first time derivative of the conductivity at a time when the second time derivative reaches zero, indicating that the oxidation reaction is complete, from the change in the total conductivity measurement, the remainder being equal to the contribution to conductivity made by oxidation of the organic content of the water.

Abstract: A method and kit for the optical detection of proteins and nucleic acids in a matrix, such as polyacrylamide electrophoresis gels. The method comprises fixing the proteins and nucleic acids in the matrix using aromatic sulfonic acids having tertiary amines capable of forming coordination complexes with silver ion.