47results about How to "Detection line low" patented technology

The invention provides a preparation method of a polydopamine-noble metal composite nano material with a Raman-enhanced effect. The preparation method comprises the steps: (1) performing oxidizing auto polymerization on dopamine to form spherical polydopamine particles; (2) adding a noble metal precursor solution into an aqueous solution of the polydopamine to prepare polydopamine-noble metal nanoparticles; and (3) after centrifugal washing of the nanoparticles, storing the same at room temperature. Compared with the prior art, by taking the polydopamine particles as a template, nanoparticles of core-shell structures with controllable metal nanoparticle loading amount and adjustable distance are synthesized by regulating the reaction temperature and the rate of charge, and the nanoparticles have a remarkable SERS enhancing effect. The method has the advantages of being simple and convenient to prepare, relatively strong in Raman-enhanced effect, high in repeatability and good in stability.

The invention provides a method for preparing H2O2 biosensor of MWNTs-IL / Cyt c / GCE, which includes the following steps: performing chemical reaction between a multi-wall carbon nano tube subjected to carboxylation and ionic liquid subjected to amidation, so as to form a carbon nano tube subjected to amidation; and then fixing a cytochrome c on a glassy carbon electrode modified by the carbon nanotube subjected to amidation to increase the adsorption and catalytic activity of the cytochrome c. Through adopting the method, the detection line of the hydrogen peroxide obtained from the ampere response can reach 1.3*10<-8>M, and the MWNTs-IL / Cyt c / GCE has sensitive response to the oxidation of the hydrogen peroxide.

The invention discloses a histamine immunoassay method based on the characteristics of platinum-gold bimetallic nano-particle peroxidase. The method comprises the following steps: S1, labeling a histamine monoclonal antibody with a platinum-gold nano-particle to prepare a platinum-gold standard antibody nano-probe; S2, adding a sample to be tested and the nano-probe obtained in step S1 to an ELISAplate coated with a histamine antigen, and forming an antigen and platinum-gold standard antibody immune compound in a competitive immunoassay mode; S3, adding a coloring substrate solution containing 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide to the ELISA plate, performing color development, and terminating the color development with sulfuric acid; and S4, detecting the absorbance at 450 nm by a the absorption of 450 nm was measured by an enzyme-linked immunometric meter to achieve the quantitative detection of histamine in the sample. The method has the advantages of easiness in operation, high sensitivity, good stability and high sample throughput, is suitable for rapid high-throughput screening of the histamine in foods, and has a great application prospect.

The invention provides a method for measuring mercury in hydrocarbon-containing gas. The method comprises the following specific steps: applying the hydrocarbon-containing gas to be measured to a metal oxygen carrier under a heating environment; converting hydrocarbon substances, which disturb mercury measurement, into carbon dioxide and water through the oxidizing reaction of the hydrocarbon substances and the metal oxygen carrier; removing water vapor in the reacted gas; measuring the mercury through a mercury vapor analyzer. The invention also provides a measurement device for implementing the method. The measurement device is structurally characterized in that a first mass flow meter is in sequential pipeline connection with a first valve, a first reactor, a dehumidification device and the mercury vapor analyzer, wherein the first reactor is used for accommodating the metal oxygen carrier and is arranged in an electric heating furnace; the electric heating furnace is connected with a temperature controller; the dehumidification device is connected with a refrigerator. The hydrocarbon substances can be oxidized into the carbon dioxide and the water through the metal oxygen carrier at high temperature, so that the influence on the mercury vapor analyzer caused by the hydrocarbon substances is eliminated, the hydrocarbon substances can be removed, and meanwhile the influence on the mercury vapor analyzer caused by other interference gas can be eliminated. The measurement device is easy to operate and high in applicability.

The invention provides a method for detecting stannous ions by using a rhodamine fluorescence probe. The method comprises the following steps: adding a rhodamine fluorescence probe solution to a NaOH / NaH2PO4 buffer solution to obtain multiple fluorescence probe-containing buffer systems, respectively adding different volumes of a stannous ion solution to obtain stannous ion solutions with different concentrations, standing the stannous ion solutions, detecting the fluorescence intensity at an emission wavelength of 587nm under an excitation wavelength of 560nm, and mapping through adopting the concentration of the stannous ions as abscissa and the fluorescence intensity as ordinate to obtain a linear relation curve; and adding the rhodamine fluorescence probe solution to the NaOH / NaH2PO4 buffer solution to obtain a fluorescence probe-containing buffer system, adding a stannous ion solution to be detected, standing the obtained system, detecting the fluorescence intensity at an emission wavelength of 587nm under an excitation wavelength of 560nm, and calculating the concentration of the stannous ions. The method has the advantages of simple operation, fast detection, high sensitivity and good selectivity.

The invention discloses an ionic liquid film fixed cholesterol enzyme / Prussian blue-based modified electrode. A cholesterol oxidase is fixed on an electrode through ionic liquid to form a modified layer on the surface of the electrode, and concretely, the cholesterol oxidase is dispersed into hydrophobic ionic liquid to form a cholesterol enzyme ionic liquid stock solution, then, the solution is coated on the surface of the electrode on which Prussian blue is electrodeposited, and finally, the ionic liquid film fixed cholesterol enzyme / Prussian blue-based modified electrode is obtained after vacuum drying. The modified electrode disclosed by the invention can be directly used for detecting cholesterol and has the characteristics of high sensitivity and low detection limit.

The invention discloses a preparation method of a zirconium dioxide / porous polyaniline modified electrode. The preparation method comprises the following steps: (1) dispensing a silicon dioxide microsphere layer on a glass carbon electrode subjected to cleaning treatment and airing at the room temperature; (2) soaking the electrode modified in the step (1) in a 0.25M phenylamine and 0.6M sulfuric acid solution and performing electropolymerization to form a polyaniline film layer; (3) soaking the electrode modified in the step (2) in an HF solution for etching for 45min, and washing with a great amount of water; and (4) soaking the electrode modified in the step (3) in a 5mM ZrOCl2 solution containing 0.1M KCl, performing electro-deposition to form a ZrO2 nano particle layer, and washing with the water to obtain the zirconium dioxide / porous polyaniline modified electrode. The zirconium dioxide / porous polyaniline modified electrode is prepared by the electropolymerization and the electro-deposition, and compared with the other methods, the method for preparing the zirconium dioxide / porous polyaniline modified electrode is simple, rapid, economic and effective.

The invention discloses an immunoassay method based on an iron (II) and phenanthroline system and glucose-encapsulated liposome. According to the method, glucose-loaded liposome with a high-efficiencyloading capacity and glucose oxidase with a high-efficiency catalytic property are used for signal amplification, and the ferrous ion and phenanthroline system is used as a visual visible chromogenicgroup. The method can be used for high-resolution colorimetric semiquantitative detection of the concentration of streptomycin by a smart mobile phone; along with the increase of the concentration ofstreptomycin, the color of a detection solution is changed from bright yellow to reddish orange, and quantitative detection is performed by an ultraviolet and visible spectrophotometer. The glucose-loaded liposome preparation process is simple and low in cost; the colorimetric detection method of the ferrous ion and phenanthroline color development system is simple and convenient, fast in color development speed and high in sensitivity, and a new sensitive and stable-property visual detection method is provided for food safety detection.

The invention discloses a preparation method of a zirconium dioxide / porous polyaniline modified electrode. The preparation method comprises the following steps: (1) dispensing a silicon dioxide microsphere layer on a glass carbon electrode subjected to cleaning treatment and airing at the room temperature; (2) soaking the electrode modified in the step (1) in a 0.25M phenylamine and 0.6M sulfuric acid solution and performing electropolymerization to form a polyaniline film layer; (3) soaking the electrode modified in the step (2) in an HF solution for etching for 45min, and washing with a great amount of water; and (4) soaking the electrode modified in the step (3) in a 5mM ZrOCl2 solution containing 0.1M KCl, performing electro-deposition to form a ZrO2 nano particle layer, and washing with the water to obtain the zirconium dioxide / porous polyaniline modified electrode. The zirconium dioxide / porous polyaniline modified electrode is prepared by the electropolymerization and the electro-deposition, and compared with the other methods, the method for preparing the zirconium dioxide / porous polyaniline modified electrode is simple, rapid, economic and effective.

The invention discloses a double-signal miRNA-21 detection method based on three-dimensional DNA Walker and MOF-Fe (II) induced generation of Turnskill blue. The method comprises the following steps: mixing and incubating avidin modified MB and a biotin modified hairpin strand H1, and then mixing and incubating with a hairpin strand H2-Au NP-GOx probe and a miRNA-21 solution, so as to obtain a DNA Walker product; adding the DNA Walker product into a glucose solution to carry out catalytic reaction, and carrying out magnetic separation to obtain a solution containing hydrogen peroxide; and enabling the MOF-Fe (II) to react with a solution containing hydrogen peroxide and induce generation of TB on an electrode to realize electrochemical detection, or enabling the MOF-Fe (II) solution containing hydrogen peroxide to induce generation of TB in the solution to realize photo-thermal detection, so that the method can be used for dual-signal detection of miRNA, and is low in miRNA target object detection lower limit and high in selectivity.

The invention provides a method for detecting trivalent chromic ions by using a rhodamine fluorescent probe, and is characterized in that the method includes the steps: preparing trivalent chromic ion solutions with different concentrations, allowing to stand, under a condition of the excitation wavelength of 560 nm, detecting the fluorescence intensity at the emission wavelength of 582 nm, and with the concentration of chromium ions as an abscissa and the fluorescence intensity as an ordinate, mapping to obtain a linear relationship curve; adding a rhodamine fluorescent probe solution to an NaOH / NaH2PO4 buffer solution to obtain a buffer system containing the fluorescent probe, adding a to-be-tested trivalent chromic ion solution, allowing to stand, under a condition of the excitation wavelength of 560 nm, detecting the fluorescence intensity at the emission wavelength of 582 nm, and according to the linear relationship curve obtained in the step 4, calculating the concentration of the chromium ions. The fluorescent probe can selectively identify the trivalent chromic ions, is free from the interference of other common ions, and is high in fluorescence intensity.

The invention discloses a metal ion-labeled immunoreaction single-pulse detection method, which realizes single-pulse signal detection by using inductively coupled plasma or microwave plasma mass spectrometry analysis technology, and uses metal nanoparticles to mark the immune reaction, and further utilizes inductively coupled Plasma or microwave plasma mass spectrometry technology detects the pulse signal of metal ions that mark the immune reaction, so as to achieve the purpose of indirect detection of the analyte.

The invention discloses a preparation method and a use of a functional graphene-loaded palladium nanoparticle composite material. The preparation method comprises the following steps of carrying out ultrasonic dispersion of graphene in water to obtain a graphene suspension liquid, adding a pyrenetetrasulfonic acid sodium salt aqueous solution into the graphene suspension liquid, carrying out heating stirring for 8-15h, carrying out centrifugal filtration to obtain functional graphene, dispersing the functional graphene in water to obtain a functional graphene suspension liquid, adding a palladium chloride solution into the functional graphene suspension liquid, adding a sodium borohydride solution into the mixed solution, carrying out heating stirring for 8-15h, and carrying out centrifugal filtration to obtain the functional graphene-loaded palladium nanoparticle composite material. Through functionalization of graphene by the pyrenetetrasulfonic acid sodium salt, dispersibility and stability of graphene and palladium nanoparticles are improved. A glassy carbon electrode modified by the functional graphene-loaded palladium nanoparticle composite material has a good nitroaromatic compound catalysis performance, a low nitroaromatic compound detection limit, a wide nitroaromatic compound detection linear range, high nitrobenzene detection sensitivity, a nitrobenzene detection linear range of 170-8ppb, and a nitrobenzene detection limit of 0.62ppb.

The invention relates to preparation and application of a competitive immunosensor, in particular to a competitive immunosensor which takes a composite material of UiO-66 and gold nanoparticles (UiO-66 / Au) as a sensing platform and NH2-MIL-125 as a marker, and belongs to the technical field of novel functional materials and biosensing. The UiO-66 / Au has excellent electrical conductivity and largespecific surface area, so that the electron transfer process can be effectively promoted and the roles of amplifying the current signal and increasing the sensitivity of the sensor are played; and theNH2-MIL-125 synthesized by utilizing an one-pot method has large steric hindrance to ensure that the electron transfer can be hindered and the current signal is reduced, so that the changing value ofthe current signal is increased, the content of a target can be detected by utilizing the change of the electrochemical signal by the sensor; and therefore, the stability and the sensitivity of the immunosensor are significantly increased, the detection range is expanded and the detection limit is reduced.

The invention provides a method for detecting trivalent chromic ions by using a rhodamine fluorescent probe, and is characterized in that the method includes the steps: preparing trivalent chromic ion solutions with different concentrations, allowing to stand, under a condition of the excitation wavelength of 560 nm, detecting the fluorescence intensity at the emission wavelength of 582 nm, and with the concentration of chromium ions as an abscissa and the fluorescence intensity as an ordinate, mapping to obtain a linear relationship curve; adding a rhodamine fluorescent probe solution to an NaOH / NaH2PO4 buffer solution to obtain a buffer system containing the fluorescent probe, adding a to-be-tested trivalent chromic ion solution, allowing to stand, under a condition of the excitation wavelength of 560 nm, detecting the fluorescence intensity at the emission wavelength of 582 nm, and according to the linear relationship curve obtained in the step 4, calculating the concentration of the chromium ions. The fluorescent probe can selectively identify the trivalent chromic ions, is free from the interference of other common ions, and is high in fluorescence intensity.

The invention discloses a preparation method of a magnetic nano mimic enzyme, and relates to the technical field of mercury ion detection, and the preparation method comprises the following steps: (1) dissolving cobalt chloride hexahydrate, ferric trichloride hexahydrate and sodium hydroxide in ethylene glycol, stirring and dissolving, and carrying out ultrasonic treatment to form a solution, the molar ratio of cobalt chloride hexahydrate to ferric trichloride hexahydrate to sodium hydroxide being 1: 2: 16; (2) carrying out hydrothermal reaction on the solution in the step (1), and cooling to room temperature after the reaction; and (3) washing the reaction product in the step (2) under the attraction of a permanent magnet, and then drying. The invention also provides the magnetic nano mimic enzyme prepared by the method and application of the magnetic nano mimic enzyme in mercury ion detection. The preparation method has the beneficial effects that only the precursor and the reducing agent are adopted, the magnetic nano mimic enzyme is synthesized through a simple hydrothermal method, and the reaction condition is mild; the strong magnetic property of the magnetic nano mimic enzyme is fully utilized, the washing process is simplified, and the synthesized magnetic nano material can be recycled and reused.

The invention discloses an ion-selective electrode flow injection analyser. Ports of a three-way valve are connected with an ion selective electrode (ISE), a No.1 channel of a six-way valve and a peristaltic pump; the other end of the peristaltic pump A is connected with a total ionic strength adjustment buffer (TISAB) bottle; two ends of a peristaltic pump B are connected with a carrier liquid bottle and a No.6 channel; two ends of a peristaltic pump C are connected with a waste liquor bottle and a No.4 channel; a sample liquid bottle is connected with a No.3 channel; two ends of a separation column are connected with a No.2 channel and a No.5 channel; the bottom end of the ISE is provided with an ISE electrode membrane, a reflux tube is arranged below the ISE electrode membrane, and a gap between the reflux tube and the ISE electrode membrane is 0.5mm; a reference electrode and the ISE electrode are connected through a gravity separator consisting of an A-B channel and a C-D channel; inclination angles of the A-B channel and the C-D channel are 35 degrees and 45 degrees; and channels on two sides of the reflux tube are connected with the ends B and D of the gravity separator. The ion-selective electrode flow injection analyser has the advantages that: experimental reagents are saved, a detection line can be reduced, and a phenomenon that the detection limit is improved due to the dissolution of a salt type ISE membrane is inhibited.

The invention relates to a preparation method and application of a fluorescent probe that can be used for ammonia gas detection and a test paper thereof, and belongs to the technical field of analytical chemistry. The fluorescent probe of the present invention takes the benzo[a]phenoxazine nucleus as the parent nucleus, and its chemical structure is shown in formula (I). The fluorescent probe with NH 3 When acting, the intramolecular charge transfer effect is significantly enhanced, showing red fluorescence, realizing NH 3 detection. In addition, the fluorescent probe of the present invention can also be prepared into a test paper to realize the rapid detection of ammonia gas, and also has very important practical value for the determination of ammonia gas content in the ammonia breath experiment and the diagnosis of Helicobacter pylori.

The invention belongs to the technical field of nano materials and particularly relates to aminated mesoporous silica-glucose-manganese dioxide nanocomposite and a preparation method and application thereof. The nanocomposite is prepared from manganese dioxide nanosheet and aminated mesoporous SiO2 nanosphere containing glucose, wherein the surface of the aminated mesoporous SiO2 nanosphere is coated by the manganese dioxide nanosheet, the particle size of the aminated mesoporous SiO2 nanosphere is 40 to 60nm, and the hole diameter is 2 to 3nm. The preparation method of the aminated mesoporous silica-glucose-manganese dioxide nanocomposite comprises the steps of preparing aminated mesoporous SiO2 and MnO2 nanosheet, then dispersing the aminated mesoporous SiO2 into a glucose water solution and finally connecting the MnO2 nanosheet to the surface of aminated MSN. According to the aminated mesoporous silica-glucose-manganese dioxide nanocomposite and the preparation method and application thereof, PGM is utilized to detect; thus, the content of GSH in a sample of the aminated mesoporous silica-glucose-manganese dioxide nanocomposite can be quantitatively detected, a detection line is low, and flexibility is high.