75 results about "Ultra trace" patented technology

A device, system and method for detecting and measuring concentrations of elements in fluids comprises: flowing a fluid through a central flow interelectrode gap of an ionic preconcentration cell separating an upper high specific surface area electrode from a lower high specific surface area electrode of the ionic preconcentration cell by a predetermined interelectrode gap width; and applying a voltage differential between the upper high surface area electrode and the lower high surface area electrode while the fluid is flowing through the central flow interelectrode gap. As such, this cell that utilizes its inherent capacitance for double layer formation to extract ultra-trace levels of ionic contaminants from fluids in order to enhance detection by x-ray fluorescence analysis.

A sol-gel poly-THF coating was developed for high-performance capillary microextraction to facilitate ultra-trace analysis of polar and nonpolar organic compounds. Parts per quadrillion level detection limits were achieved using Poly-THF coated microextraction capillaries in conjunction with GC-FID. Sol-gel Poly-THF coatings showed extraordinarily high sorption efficiency for both polar and nonpolar compounds, and proved to be highly effective in providing simultaneous extraction of nonpolar, moderately polar, and highly polar analytes from aqueous media. Sol-gel poly-THF coated microextraction capillaries showed excellent thermal and solvent stability, making them very suitable for hyphenation with both gas-phase and liquid-phase separation techniques, including GC, HPLC, and CEC. In CME-HPLC and CME-CEC hyphenations, sol-gel poly-THF coated microextraction capillaries have the potential to provide new levels of detection sensitivity in liquid-phase trace analysis, and to extend the analytical scope of CME to thermally labile-, high molecular weight-, and other types of compounds that are not amenable to GC.

The invention provides a novel series-parallel connection mass spectrum device system. The system comprises mass spectrum necessary basic subsystems, such as a set of quadrupole mass filter system, a special quadrupole rod/linear ion trap mass analyzer system, an ion guidance system, a quadrupole deflector, a hyperbolic quadrupole rod mass analyzer and ion counter system, a low air pressure linear ion trap mass spectrometer and electron multiplier system, a flight time mass spectrum system, a multi-path gas flow control system, a vacuum gauge, a multi-section differential motion vacuum system and the like. Furthermore, the invention provides a method for operating above systems to perform quantitative analysis in a triplet quadrupole rod mode, qualitative analysis in a quadrupole filtering medium combined high/low air pressure ion trap mode, and quick/high-mass precision analysis in a quadrupole filtering combined flight time mass spectrum mode on ultra-trace materials in a complex matrix, a method for utilizing an effective combination of three different mass analyzers to achieve optimal ion optical parameter adjustment and a method for performing high-precision qualitative and quantitative analysis on the ultra-trace materials.

An atomic force microscope (AFM) tip is used to selectively produce surface enhanced Raman scattering (SERS) for localized Raman spectroscopy. Spectra of thin films, undetectable with a Raman microprobe spectrometer alone, are readily acquired in contact with a suitably gold-coated AFM tip. Similarly, an AFM tip is used to remove sample layers at the nanometer scale and subsequently serve as a SERS substrate for ultra-trace analysis. This demonstrates the interface of an AFM with a Raman spectrometer that provides increases sensitivity, selectivity and spatial resolution over a conventional Raman microprobe. An AFM guiding the SERS effect has the potential for targeted single molecule spectroscopy.

The invention discloses a preparation method of surface enhanced Raman substrate (SERS). The preparation method comprises the following steps: step a, forming a surface enhanced Raman substrate (SERS) on a surface enhanced layer formed by attaching nano silver particles on a basic layer; step b, preserving the surface enhanced Raman substrate (SERS) formed in the step a in the protection of inert gas. Because the nano silver particle substrate is preserved in the protection of nitrogen gas, the surface will not be oxidized after a long period, thus the substrate, which has been preserved for a long time, still has a very good enhancing effect when the substrate is applied to an SERS substrate. The SERS has ultrahigh analysis sensitivity, is suitable for the detection of ultra-trace samples, has the advantages of simple preparation, short production time, low cost, and suitability for batch production, and provides conditions for promoting the SERS technology to be used in the fields of national security, environmental supervision, food safety, medical treatment and public health, and the like.

Means for reducing an arsenic ion concentration in the solution to the degree of ultra trace amount are provided. Ammonium molybdate is supported by a nanostructure material by mixing the nanostructure material, which is obtained after the nanostructure material such as an alumina reacts with a surfactant, in the solution containing the ammonium molybdate. The nanostructure material supporting an arsenic ion adsorption compound such as ammonium molybdate can selectively adsorb and remove trace of arsenic ion in the solution by a room temperature treatment without a water conditioning such as pH control. In our removal system of arsenic, extra posttreatments are not needed because special pretreatments are not carried out, and special heating equipments are not used. Accordingly, our removal system of arsenic can be constructed at low cost. Furthermore, it can supply an arsenic-free solution by be constructed at multi stages.

The invention relates to a mass spectrometry instrument, more particularly to a vacuum ultraviolet light ionization source used for a high-flux gas sample analysis. The ionization source comprises an ionization source cavity and vacuum ultraviolet sources. A gas inlet is arranged at the top of the ionization source cavity and a gas sample enters the ionization source cavity through the gas inlet. Ion extraction electrodes, ion funnels and difference interface polar plates are successively arranged inside the ionization source cavity along a flow direction of the gas sample, wherein the ion extraction electrodes are coaxial, separated from each other and parallel to each other. The vacuum ultraviolet sources are arranged at side walls of the ionization source cavity; and vacuum ultraviolet lights emitted by the vacuum ultraviolet sources pass through areas between the separated polar plates and enter through hole areas of the ion extraction polar plates, wherein the vacuum ultraviolet lights are parallel to polar plates of the ion extraction electrodes. According to the vacuum ultraviolet light ionization source provided in the invention, detection sensitivity of a whole mass spectrometer system can be effectively improved; and the vacuum ultraviolet light ionization source has wide prospects for application in organic pollutant trace quantity or ultra trace quantity detection in a high-flux gas sample analysis and environment.

The invention discloses a super hydrophobic type SERS (Surface-enhanced Raman scattering) composite substrate. The composite substrate comprises a base layer with a super hydrophobic surface and an SERS substrate layer, wherein the SERS substrate layer is embedded or placed on a super hydrophobic structure surface of the substrate layer, and smaller than a solution droplet formed on the super hydrophobic surface; after the solution of detected substances drips on the SERS substrate layer, spheroidal and ellipsoidal droplets are formed on the super hydrophobic surface and can be used for fully covering the SERS substrate layer, the super hydrophobic surface and tiny SERS eliminate edge effects of the prior art, and the distribution uniformity of a detected solute on the SERS substrate layer is ensured, so that the certainty and stability of detection results are improved; the spheroidal droplets with larger specific surface areas are formed by a detected solution on the super hydrophobic surface, and the concentration of the detected solute can be increased after the spheroidal droplets are concentrated, and the detection sensitivity and accuracy can be improved, therefore, in comparison with a common SERS substrate, the substrate has better enhancement effects and ultra-high sensitivity for analysis, and is applied to detection of ultra-trace samples.

The invention discloses an ultra-trace lead-cadmium ion detection method and a detection test strip. The detection method comprises the following steps: (1) acidifying a sample; (2) removing Hg2+ and Zn2+ in the sample; (3) diluting the sample by utilizing a buffer solution to obtain a neutral sample; (4) enabling the neutral sample obtained in the step (3) to be contacted with dithizone to generate a lead-cadmium ion-dithizone complex; (5) adding sulfide solution so as to enable the lead-cadmium ion-dithizone complex to be completely reacted to generate PbS and/or CdS; (6) carrying out silver staining reaction on the mixture containing PbS and/or CdS obtained in the step (5), and determining the concentration of lead and cadmium ions in the to-be-detected sample according to the grey scale of a reaction product. The test strip comprises a substrate film and a dithizone layer, wherein the dithizone layer is compounded onto the substrate film, and the test strip is packaged in a vacuum manner. The detection method and the detection test strip are sensitive inn detection, simple in judgment, capable of reaching the standard of naked eye detection, strong in applicability and stable inn performance.

The invention provides a method for improving detection sensitivity of a SERS substrate by using a molecular template enhanced reagent, and belongs to the detection technology field. Ultra trace detection of molecules to be measured on traditional surface enhanced raman spectroscopy (SERS) substrates is increased by 2 orders of magnitude by the method, detection sensitivity of SERS is greatly improved, and prospect prospects are wide. The SERS substrate with gold or silver nanoparticles on the surface by self assembly or vapor plating is placed in an ethanol solution of probe molecules, and immersion is carried out for 20-30 hours, and the substrate is taken out; an ethanol solution of 1-hexanethiol whose concentration is 10<-4>-10<-6>M is prepared, the substrate is immersed in ethanol solution of 1-hexanethiol for 4-10 hours, ethanol is used for cleaning, drying is carried out with nitrogen, and the SERS substrate with constructed molecular templates is obtained; SERS test results show that the molecular template enhanced reagent can effectively improve detection sensitivity of the SERS substrate. The method further provides experimental evidence for researching mechanism of SERS, and at the same time, establishes a base for developing the SERS into a representation tool of material surface special properties.

In order to enhance the spectrum stability during theRaman spectrumsubstance analysis, the invention provides a Raman spectrum-based substance detection method which comprises the following steps: (1) generating a laser beam through a light source; (2) irradiating the laser beam in a sample to be detected so as to stimulate the Raman scattered light of the sample to be detected; (3) collecting the Raman scattered light to ensure that the Raman scattered light runs through an entrance slit and irradiates on a dispersion optical grating after being collimated by a collimating lens; (4) decomposing the polychromatic light into monochromatic lights with different wavelengths by the dispersion optical grating and converging the monochromatic lights onto a detection device; (5) converting the received light signal into an electric signal by the detection device; (6) processing the electric signal to obtain the spectral information of the lights with different wavelengths, and carrying out pretreatment to obtain the Raman spectrum of the sample to be detected. The detection method is accurate and reliable, has high reproducibility and ultrahigh analytic sensitivity, is suitable for the detection of ultra-trace samples and is capable of correctly obtaining the detection result.

The invention discloses a preparation method for an organic/inorganic hybrid quartz capillary monolithic column modified by single-chain DNA nucleic acid aptamer. The preparation method is performed successively through the following steps: (1) performing activation processing on the internal surface of a hollow quartz capillary; (2) weighing CTAB (hexadecyltrimethylammonium bromide) and putting into a centrifugation tube, respectively adding TEOS (tetraethyl orthosilicate), APTES (3-aminopropyltriethoxysilane), anhydrous ethanol and the like, and performing multi-step processing, so as to obtain an organic/inorganic hybrid monolithic column; (3) subsequently using methanol and pure water for flushing; (4) activating, reacting at room temperature for a period, and using a PBS (phosphate buffer saline) for repeated flushing; and (5) injecting an ochratoxin A aptamer solution into the organic/inorganic hybrid monolithic column, and performing circular reaction at room temperature and storing at a low temperature, so as to obtain the organic/inorganic hybrid quartz capillary monolithic column modified by single-chain DNA nucleic acid aptamer. The product is applied to high-selectivity separation and enrichment of trace quantity or ultra trace quantity of ochratoxin, aflatoxin and other substances in complex biological samples and food.

The invention discloses a surface-enhanced Raman substrate (SERS) of ground glass, and a preparation method thereof. The SERS comprises a base layer and a surface-enhanced layer. The surface-enhanced layer is adhered on the ground surface of the ground glass. With the method, a noble metal surface-enhanced layer is directly formed on the ground glass having a roughness with a micron order of magnitude; no etching surface is necessary to be formed on the base layer; the noble metal layer is not necessary to be roughed; and the formed substrate has extremely good enhanced effect and ultra-high analytical sensitivity. The SERS is suitable for the detection of ultra trace samples. The most prominent is that the SERS is simple in preparation, short in production period and relatively low in cost, is suitable for large-scale production, and provides conditions for promoting wider applications of the SERS technology in the fields of homeland security, environmental monitoring, food security, health care, etc.

The invention discloses a methylmercury ion imprinted magnetic microsphere, and a preparation method and application thereof. The methylmercury ion imprinted magnetic microsphere is an ion imprinted polymer prepared by synthesizing methylmercury ion physical structure three-dimensional holes in the surface of a ferroferric oxide magnetic microsphere. According to the characteristics that the ion imprinted polymer with the methylmercury ion structure three-dimensional holes has high specific adsorption capacity to methylmercury ions, and ferroferric oxide magnetic microspheres can be quickly collected and separated through magnet, specific, rapid and high-expansion preconcentration and separation of ultra-trace methylmercury in water can be realized.

The invention discloses a detection method of tetracycline antibiotics in a water sample, wherein the method comprises the steps: firstly, pretreating a water sample with a magnetic material, and then determining the content of the tetracycline antibiotics in a filtrate by high performance liquid chromatography and tandem mass spectrometry. The method provided by the invention can detect trace or ultra trace tetracycline antibiotics in water bodies, and has the advantages of simple and fast operation, green environmental protection, reliable results, low detection limit and good reproducibility.

Provided is a method for quantification collecting heavy metal cations in water environment. The steps includes pre-treating dialysis membranes, pre-treating water-soluble poly-aspartic acid binding agents, placing collecting devices containing the binding agents in the water environment, the dialysis membranes is downward in placement, and fixing the collecting devices, storing the collecting devices for 1-120 days, and taking out and detecting the collecting devices; taking out the binding agents gathered with the heavy metal cations in every collecting device by 50%-80% of the volume of the whole volume, fixing volume by hydrochloric acid so as to detect accumulation volume of the heavy metal cations in the binding agents, and calculating density of the heavy metal cations in the water environment. The method has the advantages of using the collecting devices for sampling in original positions, being simple in the collection devices, having a gathering function, actually reflecting substantial existence states through detecting results, being low in detecting limit, and capable of detecting ultra-trace heavy metal cations, having no pollution to the environment, and being capable of completely reflecting change of a water environment system in a certain period.

The invention provides a capillary analysis detection method based on ultrasonic aggregation and belongs to the technical field of analytical chemistry. The method comprises the steps of mixing and injecting trace target substances, signal marker molecules and specifically modified nanoparticles into a capillary; using an ultrasonic device for aggregating the nanoparticles after markers are captured to realize aggregation of ultra-trace target substances; achieving SERS or fluorescence detection of the target substances in combination with a Raman microscope or a fluorescence microscope. The method has the advantages of being high in detection speed, low in detection limit, capable of realizing automated detection and the like, and has an important value in the aspects of realizing rapid and accurate analysis and ultra-trace detection.

The invention relates to the technical field of construction of engineering strains, and in particular relates to a construction method of engineering bacteria by surface display of black nightshade herb metallothionein. The construction method comprises the following steps: extracting a black nightshade herb metallothionein gene; taking pYES2 as a starting vector; replacing an inducible promoter on the vector with a constitutive expression promoter; separately connecting a secretion signal peptide gene and an anchoring protein agglutinin gene of saccharomyces cerevisiae; connecting the black nightshade herb metallothionein gene between the secretion signal peptide gene and the agglutinin gene; transferring an expression vector into escherichia coli; extracting vector plasmids; and transferring into the saccharomyces cerevisiae. The engineering bacteria by surface display of black nightshade herb metallothionein, constructed by the construction method provided by the invention, has stronger adsorptivity to Cd<2+>, the cadmium tolerance is also promoted significantly, and the capability of adsorbing ultra-trace heavy metals is significantly higher than that of wild yeast strains and control strains; the influence caused by pH values is small; and the engineering bacteria can adsorb a heavy metal namely cadmium in the coexistence of Cd<2+> and Cu<2+>, or Cd<2+> and Hg<2+>.

The invention discloses a preparation method and application of aptamer-modified chitosan nano fibers. The preparation method comprises the following steps: (1) preparing a chitosan solution; (2) preparing chitosan nano fibers; (3) chemical immobilization: taking the aptamer solution, adding an EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide) solution for activation, adding the chitosan nano fibers obtained in the step (2), and oscillating to react at normal temperature; and (4) after-treatment: carrying out solid-liquid separation on the reaction mixed solution obtained in the step (3) to obtain the aptamer-modified chitosan nano fibers. The aptamer-modified chitosan nano fibers are suitable for high-selectivity separation and enrichment of trace or ultra-trace mycotoxin substances and other substances in the food and environment, and have the advantages of high selectivity, high extraction capacity, high stability and simple preparation process.

The invention discloses an ultra-trace multi-biological macromolecule detecting method based on a mixed hydrogel magnetic photonic crystal barcode. The mixed hydrogel magnetic photonic crystal barcodeis obtained by utilizing a protein structure assembled by a monodisperse microsphere prepared by a microfluidic device as a template, then pouring mixed magnetic nanoparticle hydrogel into a templateand removing the template. Then a probe is coupled on the surface of the mixed hydrogel photonic crystal barcode and then integrated into the super-hydrophobic surface, the difference in wettabilityis utilized to achieve natural concentration and enrichment of a sample to achieve the purpose of ultra-trace biological macromolecule detection. Based on the stable optical characteristics such as the characteristic reflection peak of the photonic crystal, detection of a plurality of biological macromolecules, that is, multivariate detection can be achieved simultaneously. In summary, the concentrated enrichment method has the advantages of simple operation, low cost, high sensitivity and high versatility, and the method can be applied to the detection of clinical ultra-sensitive multi-microbial macromolecules.