Abstract: An improved low-cost practical method of determining beryllium or a beryllium compound thereof in a sample is disclosed by measuring fluorescence. This method discloses methods to lower the back ground fluorescence. Further, the method is extended to improved analysis of beryllium in soils by including a heating step.

Abstract: Provided is a method of measuring a biodegradation rate of a non-natural organic compound in the presence of a biodegradation medium, characterized by including: measuring a concentration of a radioactive carbon isotope 14C in a biodegradation medium; and measuring a biodegradation rate of a non-natural organic compound from a difference between the concentration of 14C in the biodegradation medium and a concentration of 14C in modern carbon. Further, a metal such as iron in the medium can be used as an internal standard. According to the method, a biodegradation rate of a non-natural organic compound can be measured safely, simply, rapidly, and accurately without providing any special measures against radiation.

Abstract: The present invention relates to the field of compression refrigeration and air conditioning. Specifically, the present invention relates to a tracer-containing compositions comprising refrigeration/heating fluid and tracer compound(s). Additionally, the present invention relates to a method for detecting tracer compounds to identify gases after leaving the custody of the original manufacturer or prior source, and the verification of authenticity. The aforementioned method provides for the detection of tracer compounds, which in turn, may alert the refrigeration industry to when dilution, adulteration, contamination or other unauthorized practices have occurred with refrigeration products.

Abstract: A method for quantitative monitoring of a gas injected into a reservoir and likely to react chemically with the injection medium includes injecting into a reservoir a mixture of the potentially reactive gas to be quantified with a low proportion of a tracer gas whose chemical inertness is total, and in determining the variation with time of the initial proportion of reactive gas that may have disappeared through conversion, by measuring the concentration variation of the tracer gas in the mixture. The tracer gas is preferably selected from the rare gas family and from isotopes thereof, unlikely to be contaminated by contact of the mixture with the injection medium, and which have physical properties such as solubility in water or diffusion coefficients as close as possible to the gas injected. The method is applicable to monitoring of the evolution and conversion of a reactive gas such as carbon dioxide or methane, injected into an underground reservoir for example.

Abstract: Tagging system and method including a plurality of particles, each particle having a miniature body and configured to provide a non-radioactive resolvable optical emission in a distinguishable pattern when selectively illuminated. The particles are set for selective release to a subsurface location. An apparatus having an elongated body configured for subsurface disposal and a chamber to house a plurality of particles therein.

Abstract: A tagged object includes a main body and a plurality of coded particles. Each coded particle may have a miniature body and be configured to provide a resolvable optical emission pattern when illuminate. The plurality of coded particles may be immobilized to the main body. A method for performing oilfield monitoring may include disposing of different types of tagged objects at different locations, wherein the different types of tagged objects each comprise a plurality of coded particles. Each of the coded particles may have a miniature body containing rare earth elements configured to produce a unique optical emission pattern when illuminated. The method may include allowing an event to trigger the release of one of the different types of tagged objects from one of the different locations. In addition, the method may include identifying the released tagged objects by unique optical emission patterns, in some cases in order to determining an occurrence location of the event.

Abstract: The present invention provides a method and apparatus or system for determining an amount of coal tar that can enter, and subsequently be displaced from, a given type of soil for a range of depths of the soil. The method and apparatus also provide verification of the pressure at which coal tar can be displaced from a given type of soil. In particular, the method and apparatus simulate the hydrostatic pressure that a soil sample encounters in the subsurface of the ground. Accordingly, the method and apparatus provide a relationship between the concentration of coal tar in the soil and the pressure required to displace the coal tar from the soil, which allows for an estimation of the amount of coal tar that may be displaced at a particular location or site. Further, the method and apparatus are adaptable for use in the laboratory or the field.

Abstract: A stable isotopic identification comprising a mathematical array of concentrations of isotopes found in a product, said mathematical array being presented in a machine readable form and comparable to analytical results whereby the product can be distinguished from other similar products, said machine readable form also being indexed through stored product information. The stored product information may be displayed when desired. By the stable isotopic identification of the invention, a product may be securely traced through manufacturing of a product, marketing of a product and the use of a product.

Abstract: A method of covertly tagging an object for later tracking includes providing a material capable of at least one of being applied to the object and being included in the object, which material includes deuterium; and performing at least one of applying the material to the object and including the material in the object in a manner in which in the appearance of the object is not changed, to the naked eye.

Abstract: The invention provides a method of online and on-site tracer generation for tagging natural gas stored in underground storage fields wherein feedstock is drawn from a feedstock source. The feedstock undergoes initial analysis to determine hydrocarbon levels. The feedstock then undergoes reaction to produce tracers such as ethylene, propylene, acetylene hydrogen and carbon monoxide. The feedstock is then analyzed to determine post reaction tracer concentration. The feedstock including generated tracers is then introduced back into the feedstock stream. Tracer levels in the pre-reaction or initial analysis of feedstock are compared with tracer levels in the post-reaction feedstock and the rate of flow of feedstock through the system is adjusted to achieve a predetermined level of tracer concentration. The level of tracer concentration will then be used to identify the particular natural gas charge in a storage field.

Abstract: The invention relates to a sample cell with a glass body comprising a gas inlet and a gas outlet and at least one orifice, a plane glass window is fused into the orifice, the shape and size of the window corresponds to the shape and size of the orifice, the orifice is limited by a rim, the rim is wider than the thickness of the window, the rim of the window is fused with the rim of the orifice. The invention further relates to a method of producing the sample cell. The window is inserted into the orifice. The rim of the orifice is heated several times from the exterior in such a way that the glass melts and a fused joint is formed between the window and the rim of the orifice. The sample cell produced by the method has a particularly rigid joint between the window and the glass body. Therefore, this glass cell is able to withstand pressures above 10 bar and allows the passage of light without lens effects owing to its plane-parallel windows. The sample cell is used in a polarizer for inert gas.

Abstract: A method and composition for identifying chemically tagged petroleum products can be achieved by adding one or more chemicals to a selected petroleum product wherein the chemical is immune to extraction from the petroleum product by conventional inexpensive absorbents, cannot be removed by extraction with acids, bases, or immiscible solvents, cannot be easily oxidized, reduced or reacted with common agents, is difficult to disguise by masking with other agents, has a low polarity, and has a boiling point in the range of the petroleum product the chemical is being added to. The presence of the chemical is determined by using ion mobility spectroscopy.

Abstract: A method for assay of an analyte by use of a material labeled with a chemiluminescent substance, which comprises adding a quencher and/or decreasing the specific activity of a chemiluminescent substance labeled probe, thereby decreasing the quantity of chemiluminescence.

Abstract: Method intended for quantitative monitoring of a gas injected into a reservoir and likely to react chemically with the injection medium.

Abstract: Compositions and methods for determining the source of treatment fluids being produced from a production formation having multiple zones by introducing a treatment composition having a tracking material into a zone in the subterranean formation, and detecting the tracking material in treatment composition that flows back from the subterranean formation.

Abstract: Disclosed is a method of determining the extent of recovery of materials injected into a oil well comprising the steps of: a) preparing a material to be injected into an oil well; b) admixing therewith a chemical tracer compound at a predetermined concentration; c) injecting the admixture into an oil well; d) recovering from the oil well a production fluid; e) analyzing the production fluid for the concentration of the chemical tracer present in the production fluid; and f) calculating the amount of admixture recovered from the oil well using the concentration of the chemical tracer present in the production fluid as a basis for the calculation. Fluorinated benzoic acids are disclosed as a preferred tracer.

Abstract: A method for monitoring hydrocarbon and water production from different production zones/sections in a hydrocarbon reservoir and/or injection wells and detection of different phenomena such as e.g. local variations in pH, salinity, hydrocarbon composition, temperature, pressure, microorganisms, and the difference between production of formation and/or injection water from various zones/sections. The method includes dividing regions around wells in the reservoir into a number of zones/sections, and injecting or placing specific tracers with unique characteristics for each zone/section into the formation in these regions such that tracers are placed as integrated parts of the well completion or placed and immobilized in these regions through injection, squeeze or by other techniques. The tracers can also be immobilized or placed on a filter, a casing or other constructions surrounding the well in each zone/section. The tracers are specific or introduced to give specific information from each zone/section.

Abstract: Disclosed is a method of determining the extent of recovery of materials injected into a oil well comprising the steps of: a) preparing a material to be injected into an oil well; b) admixing therewith a chemical tracer compound at a predetermined concentration; c) injecting the admixture into an oil well; d) recovering from the oil well a production fluid; e) analyzing the production fluid for the concentration of the chemical tracer present in the production fluid; and f) calculating the amount of admixture recovered from the oil well using the concentration of the chemical tracer present in the production fluid as a basis for the calculation. Fluorinated benzoic acids are disclosed as a preferred tracer.

Abstract: A portable pathogen detection system that accomplishes on-site multiplex detection of targets in biological samples. The system includes: microbead specific reagents, incubation/mixing chambers, a disposable microbead capture substrate, and an optical measurement and decoding arrangement. The basis of this system is a highly flexible Liquid Array that utilizes optically encoded microbeads as the templates for biological assays. Target biological samples are optically labeled and captured on the microbeads, which are in turn captured on an ordered array or disordered array disposable capture substrate and then optically read.

Abstract: A method for marking or tagging individual microparticles using a near infrared fluorophore for identification is provided. The near infrared fluorophore is included with one or more layers comprising the microparticle. Desirably, the coating layers contain colorants such as dyes and/or pigments which increases the total possible combinations that may be used to identify the marked material. There is further provided a method for marking a material using these microparticles containing a near infrared fluorophore.

Abstract: A process of using a non-radioactive tracer in the monitoring of the flow of a traced fluid is disclosed. The process includes injecting a tracer containing fluid at a first point and analyzing at least one sample from a second point in the flow of the fluid for the tracer compound. In one embodiment heavy oil is traced with a long chain hydrocarbon having a primary chain of more than 25 carbon atoms, the compound preferably being a saturated hydrocarbon. Exemplary tracer compounds include pentacosane (C25H52); hexacosane (C26H54), heptacosane (C27H56), octacosane(C28H58), nonacosane(C29H60), triacontane(C30H62), hentriacontane(C3lH64), dotriacontane(C32H66), tritriacontane (C33H68), tetratriacontane (C34H70) and the like.

Abstract: Characterization of organic contaminants in subsurface formation is performed by methods for detecting the presence of nonaqueous phase liquid in a subsurface formation, and for determining the composition and for determining the volume of nonaqueous phase liquids. Generally the methods comprise introducing one or more partitioning tracers and one or more non-partitioning tracers at one or more injection points located in the subsurface formation and measuring separation between the one or more partitioning tracers and the one or more non-partitioning tracers from one or more sampling points located in the subsurface formation to determine presence, composition and/or volume of nonaqueous phase liquid in the subsurface formation. In addition, the methods can be used to assess the performance of an attempted remediation.

Abstract: The present invention relates to a method of marking liquids using at least two markers, wherein said markers absorb in the 600-1200 nm region of the spectrum and reemit fluorescent light and the absorption range of at least one marker overlaps with the absorption range of at least one other marker. The present invention further relates to a method for detecting markers in liquids marked by the method of the invention, which comprises using light sources which emit radiation in the absorption ranges of said markers and detecting the fluorescent light reemitted by said markers, at least one of said light sources emitting radiation in the overlapping absorption range of at least one marker with that of at least one other marker and the number of light sources being less than or equal to the number of markers. The present invention further relates to liquids marked by the method of the invention.

Abstract: The invention concerns a method for determining the presence and quantity of an amine-based additive in fluids, particularly aqueous fluids used in hydrocarbon recovery such as drilling fluids, drill-in fluids, completion fluids, and the like. It was discovered that, after isolating the amine-based additive, the amount of clay stabilizer is linearly dependent upon the spectrometric count of its peak fluorescent spectrum. The method is reproducible and is not bothered by the presence of lignosulfonate and/or lignite which interferes with conventional methods.

Abstract: The presence of hydrocarbons in water is detected by contacting a water sample with an adsorbent material to extract hydrocarbons from the water sample and then contacting the adsorbent material with a solvent for the hydrocarbons. A developer such as a miscible nonsolvent liquid is mixed into the solvent to produce a test mixture. The turbidity of the test mixture is observed to determine the presence of hydrocarbons in the water sample. The nonsolvent may contain at least 0.5% salt, e.g., at least 1%, preferably 5% salt, and an emulsifier. Turbidity may be measured quantitatively by measuring light scattered at 90.degree. to a test light beam or by visual comparison to a reference scale.

Abstract: A method of tagging and detecting objects is disclosed which comprises the steps of: (a) applying a volatile taggant to the object; and (b) subsequently detecting the presence of the taggant by the absorption, transmittance, reflectance, photon emission or fluorescence of the taggant and therefore a proximity of the tagged object. The present invention therefore provides optical sensing means which do not require physical separation of differing compounds for discrimination thereof.

Abstract: Characterization of organic contaminants in subsurface formation is performed by methods for detecting the presence of nonaqueous phase liquid in a subsurface formation, and for determining the composition and for determining the volume of nonaqueous phase liquids. Generally the methods comprise introducing one or more partitioning tracers and one or more non-partitioning tracers at one or more injection points located in the subsurface formation and measuring separation between the one or more partitioning tracers and the one or more non-partitioning tracers from one or more sampling points located in the subsurface formation to determine presence, composition and/or volume of nonaqueous phase liquid in the subsurface formation. In addition, the methods can be used to assess the performance of an attempted remediation.

Abstract: Use of compounds from the class of the phthalocyanines, naphthalocyanines, nickel dithiolene complexes, aminium compounds of aromatic amines, methine dyes or azulenesquaric acid dyes which have their absorption maximum in the range from 600 to 1,200 nm and/or a fluorescence maximum in the range from 620 to 1,200 nm, as markers for liquids, a process for detecting markers in liquids, and a detector suitable for this purpose.

Abstract: A liquid hydrocarbon fuel composition comprises at least one tagging agent and a mixture of hydrocarbon components having boiling points in the range of about 100 degrees F. to about 800 degrees F. The tagging agent is present at a concentration in the range of from about 0.5 ppb to about 500 ppb. The tagging agent is elutable by chromatographic analysis of the liquid hydrocarbon fuel composition apart from the hydrocarbon components of the fuel composition. The tagging agent is formed from an organic compound containing elements found at natural isotopic abundance. Preferably, two or more tagging agents are employed in the fuel so that each fuel composition can be assigned a unique tagging agent composition. Analysis techniques are also disclosed.

Abstract: Methods for marking a liquid and methods and systems for identifying marked liquids. A liquid can be marked for identification purposes with at least a first marker and a second marker. Each of the markers is miscible with the liquid. The markers are mixed in the liquid so that the ratio of the concentration of the first marker to the concentration of the second marker is substantially equal to a predetermined value. Thus, when a system according to the invention measures the concentrations of the first and second markers, the system can compare the ratio of the measured concentration of the first marker to the measured concentration of the second marker with a look up table of the predetermined values to provide information concerning the identity of the liquid. In a preferred embodiment, the concentration of the markers is measured using an absorption spectrometer.

Abstract: A method for assay of an analyte by use of a material labeled with a chemiluminescent substance, which comprises adding a quencher and/or decreasing the specific activity of a chemiluminescent substance labeled probe, thereby decreasing the quantity of chemiluminescence.

Abstract: Method for tagging hydrocarbons and for detecting the presence of tagged hydrocarbons in a hydrocarbon mixture. The method can be utilized to tag gasoline, diesel fuel, heating oil, lubricating oil or crude petroleum. The hydrocarbon to be tagged is blended with a relatively small amount of a fluorescent dye. The presence of the tagged hydrocarbon is subsequently determined by exciting the dye to fluoresce at wavelengths in the higher portion of the visible spectral region or the lower portion of the near infrared spectral region.

Abstract: A porous material (10) is contaminated with soil (14). Optionally, the porous material is partially shielded by an impermeable layer. The contaminated porous material is packaged and shipped to a user site. The contaminated porous material is removed from the package and placed in an automated processor containing medical equipment (22). The medical equipment and porous material are subjected to a cleaning, disinfecting, or sterilizing cycle in the processor. The cleaning process is evaluated by examining the porous material with an infrared or other electronic reader (24) to determine the presence of remaining soil which has not be removed during the cleaning, disinfecting, or sterilizing cycle.

Abstract: The presence of hydrocarbons in soil is detected by immersing a soil sample in a water-miscible solvent capable of dissolving the hydrocarbons to extract hydrocarbons from the soil into the solvent. An aqueous developer is mixed into the solvent to produce a test mixture. The turbidity of the test mixture is observed to determine the presence of hydrocarbons in the soil. The aqueous developer may contain at least 0.5% salt, e.g., at least 1%, preferably 5% salt, and an emulsifier. Turbidity may be measured quantitatively by measuring light scattered at 90.degree. to a test light beam or by visual comparison to a reference scale.

Abstract: A method for the quantitative determination of dissolved oxygen in a liquid fuel includes the steps of doping a sample of the fuel with a preselected concentration of a probe material including a luminophor which exhibits luminescence of wavelength which is quenched by oxygen dissolved in the fuel, illuminating the fuel with light from a coherent light source, such as a laser, of a wavelength which induces the luminescence in the luminophor, and thereafter measuring the change with time of the luminescence from the luminophor in the fuel and determing from the change with time of the luminescence the concentration of oxygen in the fuel.

Abstract: Characterization of organic contaminants in subsurface formation is performed by methods for detecting the presence of nonaqueous phase liquid in a subsurface formation, and for determining the composition and for determining the volume of nonaqueous phase liquids. Generally the methods comprise introducing one or more partitioning tracers and one or more non-partitioning tracers at one or more injection points located in the subsurface formation and measuring separation between the one or more partitioning tracers and the one or more non-partitioning tracers from one or more sampling points located in the subsurface formation to determine presence, composition and/or volume of nonaqueous phase liquid in the subsurface formation. In addition, the methods can be used to assess the performance of an attempted remediation.

Abstract: A water-immiscible organic fluid is tagged and identified by tagging the organic fluid with between about 0.25 and about 100 ppm of a marker compound having the formula: ##STR1## where the OH groups are either ortho or para to the diazo moieties, and the Xs are the same or different and are selected from C.sub.1 -C.sub.12 -alkyl, Cl, Br, F, NH.sub.2, CN, NO.sub.2, NH(C.sub.1-3 -alkyl) and N(C.sub.1-3 -alkyl).sub.2, and the fluid is identified by extracting the tagged fluid with an alkaline aqueous extractant having a pH above about 12 and containing, based on 100 parts by weight of said extractant, between about 10 and about 60 parts by weight of an organic cosolvent having the formula:R.sup.1 --O--R.sup.2 --NH.sub.2 (II)where R.sup.1 is C.sub.1 -C.sub.3 -alkyl, and R.sup.2 is C.sub.2 -C.sub.6 -alkylene.

Abstract: A method is disclosed for identifying the source of a transported chemical shipment. The method employs either a chemical element or an organic compound with one or more atoms that are non-radioactive isotopes generally not found in nature. A small quantity of the isotopic compound is introduced into the storage vessel containing the chemical to be transported prior to shipment of the chemical. Upon arrival at its destination point, a sample of the chemical shipment is analyzed. Matching the isotopic compound found in the chemical with the isotopic compound introduced into the storage vessel prior to shipment is indicative that the shipped chemical is identical to the chemical received. Non-radioactive materials may further be employed for detecting the source of a newly introduced contaminant in a water supply. The chemical substance may be a non-radioactive isotope of the chemical shipment being transported.

Abstract: Rare elements, which can be selected from Ni, Cu, W, Li, N, Ce, Sn, Y, Nd, Nb, Co, La, Pb, Ga, Mo, Th, Cs, Ge, Sm, Gd, Be, Pr, Se, As, Hf, Dy, U, B, Yb, Er, Ta, Br, Ho, Eu, Sb, Tb, Lu, Tl, Hg, I, Bi, Tm, Cd, Ag, In, Se, Pd, Pt Au, He, Te, Rh, Re, Ir, Os, and Ru can be used to tag commodities, including explosive materials, with a unique tagging agent.

Abstract: A method for tagging hydrocarbons and for detecting the presence of tagged hydrocarbons in a hydrocarbon mixture. The method can be utilized to tag gasoline, diesel fuel, heating oil, lubricating oil or crude petroleum. The hydrocarbon to be tagged is blended with a relatively small amount of a fluorescent dye. The presence of the tagged hydrocarbon is subsequently determined by exciting the dye to fluoresce at wavelengths in the higher portion of the visible spectral region or the lower portion of the rear infrared spectral region.

Abstract: Use of compounds from the class of the phthalocyanines, naphthalocyanines, nickel dithiolene complexes, aminium compounds of aromatic amines, methine dyes or azulenesquaric acid dyes which have their absorption maximum in the range from 600 to 1,200 nm and/or a fluorescence maximum in the range from 620 to 1,200 nm, as markers for liquids, a process for detecting markers in liquids, and a detector suitable for this purpose.

Abstract: The presence of hydrocarbons in soil is detected by immersing a soil sample in a water-miscible solvent capable of dissolving the hydrocarbons to extract hydrocarbons from the soil into the solvent. An aqueous developer is mixed into the solvent to produce a test mixture. The turbidity of the test mixture is observed to determine the presence of hydrocarbons in the soil. The aqueous developer may contain at least 0.5% salt, e.g., at least 1%, preferably 5% salt, and an emulsifier. Turbidity may be measured quantitatively by measuring light scattered at 90.degree. to a test light beam or by visual comparison to a reference scale.

Abstract: A method for tagging hydrocarbons and for detecting the presence of tagged hydrocarbons in a hydrocarbon mixture. The method can be utilized to tag gasoline, diesel fuel, heating oil, lubricating oil or crude petroleum. The hydrocarbon to be tagged is blended with a relatively small amount of a fluorescent dye. The presence of the tagged hydrocarbon is subsequently determined by exciting the dye to fluoresce at wavelengths in the higher portion of the visible spectral region or the lower portion of the near infrared spectral region.

Abstract: A method of determining the dosage of dust control agents applied to coal is disclosed. The method comprises the steps of: (1) treating the coal, with a small amount of a dust control agent containing a compatible fluorescent dye; (2) extracting the treated coal with a polar solvent for the freeze-release agent and determining the fluorescence of such extract; (3) extracting a similar treated coal sample to which a known amount of the dust control agent has been further added and determining the fluorescence of this extract; (4) setting up a proportionality between the fluorescence values of extracts (2) and (3) with the corresponding dosages of dust control agents and solving for the unknown dosage originally applied to the coal.

Abstract: A method for tagging hydrocarbons and for detecting the presence of tagged hydrocarbons in a hydrocarbon mixture. The method can be utilized to tag gasoline, diesel fuel, heating oil, lubricating oil or crude petroleum. The hydrocarbon to be tagged is blended with a relatively small amount of a fluorescent dye. The presence of the tagged hydrocarbon is subsequently determined by exciting the dye to fluoresce at wavelengths in the higher portion of the visible spectral region or the lower portion of the near infrared spectral region.

Abstract: A method for the quantitative determination of oil in a soil matrix is provided, in which the method involves: extracting a soil sample with a solvent in the presence of a drying agent to provide an extract containing oil, if present in the soil sample, wherein the solvent is capable of complete solvation of oil and is completely miscible with water; filtering the extract; combining the filtered extract with water in the presence of an emulsifier to form an assay sample; and determining the amount of oil in the soil sample by measuring the turbidity of the assay sample to provide a turbidimetric response for the assay sample which correlates to concentration of oil present in the assay sample and comparing the turbidimetric response to a standard curve prepared from performing the methods on soil samples of known oil content. A kit for performing the method is also provided.

Abstract: Rare elements, which can be selected from Ni, Cu, W, Li, N, Ce, Sn, Y, Nd, Nb, Co, La, Pb, Ga, Mo, Th, Cs, Ge, Sm, Gd, Be, Pr, Se, As, Hf, Dy, U, B, Yb, Er, Ta, Br, Ho, Eu, Sb, Tb, Lu, Tl, Hg, I, Bi, Tm, Cd, Ag, In, Se, Pd, Pt, Au, He, Te, Rh, Re, Ir, Os, and Ru can be used to tag commodities, including explosive materials, with a unique tagging agent.

Abstract: A method is disclosed for identifying the source of a transported chemical shipment. The method employs either a chemical element or an organic compound with one or more atoms that are non-radioactive isotopes generally not found in nature. A small quantity of the isotopic compound is introduced into the storage vessel containing the chemical to be transported prior to shipment of the chemical. Upon arrival at its destination point, a sample of the chemical shipment is analyzed. Matching the isotopic compound found in the chemical with the isotopic compound introduced into the storage vessel prior to shipment is indicative that the shipped chemical is identical to the chemical received. Non-radioactive materials may further be employed for detecting the source of a newly introduced contaminant in a water supply. The chemical substance may be a non-radioactive isotope of the chemical shipment being transported.

Abstract: A method of monitoring the movement of a material which comprises adding to the material, as a microtrace additive, DNA molecules, sampling the resulting material after movement thereof and detecting the presence of said microtrace additive in the sample. The method is particularly suitable for use in monitoring the movement of oil shipments and the microtrace additive is selected such that it will remain in the oil phase in the event the oil is dispersed in water e.g. sea water.

Abstract: This invention provides a method for imparting invisible markings for identification purposes to petroleum hydrocarbons by incorporating one or more infrared fluorescing compounds therein. Certain infrared fluorophores from the classes of squaraines (derived from squaric acid), phthalocyanines and naphthalocyanines are useful in providing invisibly marked petroleum hydrocarbons such as crude oil, lubricating oils, waxes, gas oil (furnace oil), diesel oil, kerosene and in particular gasoline. The near infrared fluorophores are added to the hydrocarbons at extremely low levels and are detected by exposing the marked hydrocarbon compositions to near infrared radiation having a wavelength in the 670-850 nm range and then detecting the emitted fluorescent light via near infrared light detection means.