71results about How to "High detection selectivity" patented technology

A gas sensing device (nanosensor) includes a substrate with at least a pair of conductive electrodes spaced apart by a gap, and an electrochemically functionalized semiconductive nanomaterial bridging the gap between the electrodes to form a nanostructure network. The nanomaterial may be single-walled carbon nanotubes (SWNTs) functionalized by the deposition of nanoparticles selected from the group consisting of an elemental metal (e.g., gold or palladium), a doped polymer (e.g., camphor-sulfonic acid doped polyaniline), and a metal oxide (e.g. tin oxide). Depending on the nanoparticles employed in the functionalization, the nanosensor may be used to detect a selected gas, such as hydrogen. mercury vapor, hydrogen sulfide, nitrogen dioxide, methane, water vapor, and / or ammonia, in a gaseous environment.

The invention relates to an electro-polymerization preparation method of an electrochemical sensor for quickly detecting EGCG (Epigallocatechin-3-Gallate), and relates to a technology in the field of active ingredient analysis and detection of an agricultural product. The method mainly comprises the following steps of: pre-treating a glass-carbon electrode; performing electro-polymerization filming on the surface of the glass-carbon electrode; and eluting template molecules to obtain EGCG molecularly imprinted membrane modified electrode, wherein the sensor can be used for quick detection of an EGCG-containing actual sample in combination of an electrochemical working station. The electro-polymerization preparation method has the advantages of high selectivity, high operation efficiency, high stability of the sensor, capability of being recycled, low cost and suitability for quick, real-time and field detection, and is suitable for quick detection of the content of the main active ingredient EGCG in tea and products thereof and quality evaluation of the tea or the tea products.

The objective of the invention is to provide an analytical method for observing the morphology of an ultrafine powder sample by using a scanning electron microscope. The method provided by the invention comprises the following steps: 1) adsorbing the ultrafine powder sample by using an electrostatically charged smooth surface of an adsorbate; 2) bonding powder adsorbed onto the adsorbate, i.e., a film, with one side of a double-sided conducting adhesive tape; 3) adhering the other side of the double-sided conducting adhesive tape onto a sample table of the scanning electron microscope; 4) carrying out gold plating on the powder adhered on the double-sided conducting adhesive tape; and 5) carrying out observation with the scanning electron microscope. With the method, a part of powder with a uniform particle size in the ultrafine powder sample can be obtained, the powder adsorbed under the action of electrostatic attraction is fine particles in the ultrafine powder sample, and only particles with similar particle sizes can be adsorbed at the same time, so a picture with uniform granularity can be obtained in observation with the scanning electron microscope.

The invention provides preparation and application of a mercury ion sensor based on photonic crystal enhanced fluorescence. The mercury ion sensor is composed of photonic crystal, a nucleic acid fluorescence molecular probe and a DNA assistant probe. The photonic crystal is used as a substrate, and strong affinity between thymidine (T) of DNA and Hg<2+> is employed to allow fluorescence group ROX labeled aptamer and a complementary sequence to compose a fluorescence detection system. A photonic crystal film is formed on a glass sheet substrate by prepared PS microspheres through vertical deposition self-assembly. Gold is sprayed on the surface of the photonic crystal; and based on Au-S bonding effect, mercapto group modified fluorescence group ROX labeled aptamer undergoes self-assembly on the surface of the photonic crystal, wherein the emission wavelength of ROX accords with the forbidden band of the photonic crystal, so fluorescence enhancing effect is achieved. According to the invention, fluorescence signal intensity of a nucleic acid fluorescence molecule is improved by using the principles of enhancement of fluorescence through the photonic crystal, so sensitivity and accuracy of sensor detection are improved.

The invention discloses a photoelectrochemical sensor for detecting methylated RNA and a detection method thereof. The photoelectrochemical sensor comprises: an electrode, and tungsten sulfide, nanogold, mercaptobenzoic acid, m6A antibody, methylated RNA, poly(U) polymerase mixed with UTP and Ru(NH3)63+ which are modified on the surface of the electrode in order. The photoelectrochemical sensor for detecting methylated RNA and the detection method thereof utilize the good photoelectric activity and biocompatibility of WS2, the good biocompatibility and conductivity of nano gold, the specific recognition performance of antibodies to antigens, employ the Poly(U) polymerase to prolong the RNA sequence and take the Ru(NH3)63+ as a signal amplification unit to achieve the high-sensitivity and high-specificity detection for methylated RNA. The detection method is simple, achieves the miniaturization of the instrument, is easy to operation and achieves the detection for the methylated RNA.

The invention discloses a europium-based coordination polymer nanosphere and a preparation method and application thereof. The preparation method of the europium-based coordination polymer nanosphere comprises the following steps of adding EuCl3.6H2O, H2BDC and polyvinylpyrrolidone to mixed solvent formed by mixing N, N-dimethylformamide and absolute ethyl alcohol, and conducting stirring till the materials are fully dissolved; then, transferring a mixed solution into a reaction still provided with a polytetrafluoroethylene inner container, and putting the reaction still in a drying oven at the temperature of 150 DEG C to leave the reaction still standing still for 12 hours; and then sequentially conducting cooling, centrifugalization, washing and vacuum drying, so that the europium-based coordination polymer nanospheres are obtained. A to-be-detected water body is added to fluorescent material suspension liquid prepared from the europium-based coordination polymer nanospheres; after being mixed uniformly, the materials are left standing still; and then a fluorescence spectrophotometer is adopted for detection, and the content of phosphate in the to-be-detected water body can be obtained. The europium-based coordination polymer nanosphere is stable in performance, not prone to photobleaching, good in water solubility, capable of effectively detecting the content of the phosphate in the water body, simple in synthesis method and low in raw material cost.

Disclosed is a method of fabricating a carbon monoxide detector and a carbon monoxide detector fabricated using the same. Particularly disclosed is a method of fabricating a carbon monoxide detector, which can operate at room temperature and process high detecting selection, and the detector fabricated using the same. The method comprises: providing a substrate having an upper surface; forming two electrode sets on the upper surface of the substrate, and the two electrode sets combined to provide an interdigitated array electrode; forming a tin dioxide layer, which covers the portion of the two electrode sets and the portion of the upper surface; and forming an organic polymer layer on the surface of the tin dioxide layer. The carbon monoxide detector comprises: a substrate having an upper surface; two electrode sets, which are located on the upper surface of the substrate; a tin dioxide layer, which covers the portion of the two electrode sets and the portion of the upper surface; and an organic polymer layer, which is located on the surface of the tin dioxide layer.

The present invention provides a chemical sensor for dopamine detection. The chemical sensor comprises gold-containing nanoparticles, wherein the surface of the gold-containing nanoparticles is modified by class A organic function small molecules and class B organic function small molecules, the class A organic function small molecules contain a boric acid group capable of acting with o-diphenol hydroxyl in the dopamine molecule, the class B organic function small molecules contain one or a plurality of materials selected from a crown ether group, an aldehyde group, succimide activated carboxyl, a phosphate ion group and a sulfonate ion group and capable of acting with the protonated terminal amino group in the dopamine molecule, and the class A organic function small molecules and the class B organic function small molecules further contain one or a plurality of materials selected from pyridine, mercapto, a primary amine group and a disulfide group so as to modify the gold-containing nanoparticles. The invention further provides a preparation method for the chemical sensor, a method for detecting dopamine, and an application of the chemical sensor in dopamine detection apparatuses.

The invention discloses a high-sensitivity glucose sensor which comprises a substrate, an electrode system and a reagent layer. The electrode system is configured on the substrate, and the reagent layer is configured on the electrode system. The electrode system comprises a working electrode and a counter electrode, wherein the working electrode is provided with a lead portion, and the counter electrode is provided with a lead portion. A detection portion is arranged on the upper face of the top of one side of the substrate. The reagent layer is configured on the electrode of the detection portion. The reagent layer comprises N-doped graphene, a carboxylation carbon nano tube and glucose oxidase. The high-sensitivity glucose sensor is good in stability, good in glucose detection selectivity, short in response time and high in sensitivity.

The invention discloses an electrochemical biosensor for detecting ampicillin and a preparation method thereof. The electrochemical biosensor includes an electrode, and nanogold, a probe DNA and an aptamer DNA that are sequentially modified on the surface of the electrode. A sequence of the probe DNA is shown as SEQ ID NO.1; and the sequence of the aptamer DNA is shown as SEQ ID NO.2. The electrochemical biosensor utilizes good biocompatibility and conductivity of the nanogold, so that amplification of a photoelectric signal is achieved, and the detection sensitivity of the ampicillin is improved. A detection method of the electrochemical biosensor is simple, an instrument is miniaturized, and an operation is easy; and the ampicillin can be detected only by simply processing the surface ofa glassy carbon electrode.

The invention relates to the technical field of analysis and determination of agricultural residues, in particular to a double-inhibition electrochemiluminescence sensor and a method for measuring glyphosate by using the same, and the method comprises the steps of preparing a double-inhibition sensor, an operation method for measuring glyphosate by using the sensor and the like.. The double-inhibition sensor utilizes the enzymatic reaction and the catalysis of copper complex peroxidase, and the synergistic effect is generated by combining two signal conversion modes, so that the detection sensitivity of the sensor is effectively improved; and the method for measuring glyphosate by using the double-inhibition electrochemiluminescence sensor is used for detecting glyphosate, and has the advantages of small interference of coexisting substances, good selectivity and high sensitivity.

An electrochemical sensor for sensing a gaseous analyte includes a substrate having at least two electrodes disposed thereon, and a carbon nanotube-polyaniline (CNT / PANI) film disposed on the substrate and in contact with at least two electrodes. The CNT / PANI film includes carbon nanotubes coated with a thin layer of polyaniline. The thickness of the polyaniline coating is such that electron transport can occur along and / or between the carbon nanotubes.

The present invention discloses 1, 3-bi (2-benzothiazolyl diazo amino) benzene (BBTAB) as one kind of diherocyclic triazene compound and its preparation process and application. The compound is prepared with m-phenylenediamine and through double diazonation and coupling with 2-amino benzothiazole. Inside alkali medium with beta-CD, the diherocyclic triazene structure of the reagent is compounded with copper ion to raise the rigidity of BBTAB and to strength the fluorescence obviously. Based on water has been said, new fluorescent analysis method of determining Cu (II) with BBTAB is established. Test on different water samples containing copper ion gives satisfactory results. In addition, BBTAB may be also used as developing agent.

The invention discloses a preparation method of a CdSe@ZnS / AgNCs composite fluorescent nanoprobe. CdSe@ZnS quantum dots are mixed with nano-silver clusters under a certain pH condition to prepare theCdSe@ZnS / AgNCs composite fluorescent nanoprobe with the CdSe@ZnS quantum dot concentration of 0.032 mg / mL and the nano-silver cluster concentration of 0.015 mg / mL. The CdSe@ZnS / AgNCs composite fluorescent nanoprobe constructed by directly mixing the CdSe@ZnS quantum dots and nano-silver clusters has the advantage of simple synthesis method. The constructed CdSe@ZnS / AgNCs composite fluorescent nanoprobe realizes oxidative degradation of the silver clusters through hydrogen peroxide to release silver ions, and the silver ions have a quenching effect on fluorescence of the CdSe-ZnS quantum dots,so the efficient detection target of hydrogen peroxide is achieved, thereby the technical problems of long detection reaction time, slow response and insufficient low detection limit of traditional technologies are solved.

The invention discloses a photoelectrochemical biosensor for detecting histone acetyltransferase activity and a preparation method thereof. The photoelectrochemical biosensor comprises an ITO electrode, stripped WS2, polydopamine, SMCC, coenzyme A, phos-tag-biotin, and streptavidin, wherein the stripped WS2, polydopamine, SMCC, coenzyme A, phos-tag-biotin, and streptavidin are sequentially modified on the surface of the electrode. According to the photoelectrochemical biosensor and the method in the invention, by utilizing good biocompatibility and conductivity of WS2 and specifically recognized avidin and biotin, quenching of a photoelectric signal is realized, and the detection sensitivity of the histone acetyltransferase is improved. The specificity of activity detection of the histoneacetyltransferase is improved by utilizing the specific binding and identification effects of maleimide in the SMCC to sulfydryl in the CoA. The detection method disclosed by the invention is simple,miniaturization of the instrument is realized, the method is easy to operate, and the detection of the activity of the histone acetyltransferase can be realized only by simply processing the surface of the ITO electrode.

The invention relates to the technical field of fluorescent porous materials, and particularly relates to a fluorescent porous material as well as a synthetic method and application thereof. A chemical formula of the fluorescent porous material disclosed by the invention is C26H16N7O9Cd2; a main ligand is 1,3,5-tri-benzene imidazolyl, an auxiliary ligand is butene diacid, and a solvent is N,N-dimethylformamide; the fluorescent porous material is prepared through a heating method of the solvent. The fluorescent porous material disclosed by the invention has simple raw materials, a preparation process is simple and easy, and the fluorescent porous material has higher heat stability and fluorescence emission property. In a process of detecting pesticide paraquat by adopting the material, thesensitivity is high, the detection selectivity is good, and the fluorescent porous material has good application prospects in the field of material science.

The invention discloses an on-line detection device and detection method for natural hydrogen sulfide and thiophane content. The on-line detection device comprises a main pipeline and a processor (6),wherein a front gas switching valve (9) and a rear gas switching valve (20) are respectively arranged at two ends of the main pipeline, a front detector (11), a hydrogen sulfide absorption module (14) and a rear detector (16) are sequentially arranged on the main pipeline from the front gas switching valve (9) to the rear gas switching valve (20), a natural gas entering pipeline (8) and an air entering pipeline (10) are connected to the front gas switching valve (9), an air discharging pipeline (17) and a natural gas discharging pipeline (19) are connected to the rear gas switching valve (20), and the processor (6) is connected with the front gas switching valve (9), the front detector (11), the rear detector (16) and the rear gas switching valve (20). The on-line detection device and method has good selectivity and high accuracy and is convenient to install and maintain, and real-time monitoring can be achieved.

The invention discloses a magnetic solid-phase extraction agent, a preparation method and an application thereof. The preparation method comprises the following steps: preparing boron nitride nanosheets from a boric acid and urea, uniformly mixing the boron nitride nanosheets and ferrous salt in water, dropwise adding ammonia water to adjust a pH value to be alkaline, heating to 85-95 DEG C, reacting, and separating and drying a magnetic solid to obtain the Fe3O4 and boron nitride nanosheet compounded magnetic solid-phase extraction agent. According to the invention, with the combination of the magnetic solid phase extraction agent and the liquid chromatography-tandem mass spectrometry, trace analysis can be performed on six plant growth regulators (indole-3-acetic acid, indole-3-butyric acid, 3-indolepropionic acid, 1-naphthylacetic acid, 2-naphthoxyacetic acid and abscisic acid) in tomatoes.

The invention aims at providing a nano material for detecting dimethoate. The nano material comprises the following components by weight percent: 97.43 to 99.31 percent of sodium silicate, 0.06 to 0.23 percent of TPPS4 and 0.63 to 2.34 percent of plant-esterase. The plant-esterase is fixed by adopting a sol-gel technology, the fixation process is a physical embedding process, a gel network is gradually formed surrounding the enzyme, the structure completeness and isotropy and biological activity of surface microstructure of the enzyme can be maintained by virtue of the moderate reaction condition, amorphous structure of the gel and biological compatibility. Then the TPPS4 enters the gel network by virtue of the micropores on the surface of the gel to be reacted with the plant-esterase so as to form aggregation on the surface of the enzyme. In the gel network, the enzyme and the aggregation have less possibility of being subjected to the unfavorable influence of unfavorable environmental factors, but also the structure is more stable, the precipitate is unlikely to form, the enzyme and the aggregation are easy to store, the reaction activity can be well protected, and the detection reaction is favored.

The invention provides an iodide ion recognition probe and a preparation method thereof. The preparation method comprises the following steps: reacting 9,9-bis(6-bromohexyl)-fluorene-2,7-dicarbaldehyde serving as a raw material with 2,5-diaminopyridine under the condition of anhydrous LiCl serving as a catalyst to obtain an intermediate product; and under the condition that N,N-dimethylacetamide is taken as a solvent, reacting the intermediate product with trimethylamine to obtain a pyridine fluorenyl fluorescent conjugated polymer. The synthesis method is simple, industrial production is easy, iodine ions can be rapidly, sensitively, accurately and economically detected, the efficiency is high in an actual application process, and the probe and method are particularly suitable for detection of micro and trace iodine ions. The fluorescence probe disclosed by the invention is high in iodine ion detection selectivity, the lowest detection limit is 4.68*10<-7> mol / L, a good linear quantitative relation is shown in a range of 0-25 [mu]mol / L, and the fluorescence probe is suitable for trace detection.

The invention provides a water-soluble fluorescein polymer probe for mercury ion detection as well as preparation and application thereof. The fluorescein polymer probe is prepared by the following steps: reacting fluorescein with hydrazine hydrate to obtain a fluorescein hydrazide intermediate, and then reacting with eight-arm polyethylene glycol benzaldehyde through Schiff base. The preparation process of the probe is simple, and the obtained probe is good in water solubility, can be directly used for fluorescence detection of mercury ions in pure water, and has the characteristics of convenience in use, high detection selectivity, sensitivity and accuracy.

The invention discloses a pb<2+> concentration detection sensor and device, a preparation method and a use method. The pb<2+> concentration detection sensor comprises a photonic crystal fiber, single-mode fibers connected with the two ends of the photonic crystal fiber and a sensitive film coating the surface of the photonic crystal fiber, and the sensitive film has a function of causing refractive index change after being combined with pb<2+>. According to the pb<2+> concentration detection sensor, the sensitive film can be combined with Pb<2+> in a solution to cause the change of the refractive index, so that the concentration of Pb<2+> in water can be effectively detected according to the change of the refractive index. The pb<2+> concentration detection sensor has the advantages of high detection selectivity and low cost.

The invention discloses an electrochemical biosensor for detecting zeatin and a preparation method thereof. The electrochemical biosensor comprises an electrode, and nanogold, probe DNA, aptamer DNA,accessory DNA and avidin-modified alkaline phosphatase which are used for modifying on the surface of the electrode in sequence, wherein sequences of the probe DNA, aptamer DNA and accessory DNA are respectively shown as SEQ ID NO. 1-SEQ ID NO. 3. According to the electrochemical biosensor disclosed by the invention, by utilizing excellent biocompatibility and conductivity of the nanogold and catalytic property of specificity of the alkaline phosphatase, the amplification of electrical signals is realized, and the detection sensitivity of the zeatin is improved. By utilizing specific binding and recognizing effects of the aptamer on the zeatin, the zeatin detection specificity is improved. The electrochemical biosensor disclosed by the invention is simple in detection method, capable of realizing instrument miniaturization and easy to operate, and the zeatin can be detected by performing simple treatment on the surface of a glassy carbon electrode only.

The invention provides a nitrogen-oxide-doped carbon dot fluorescence probe for formaldehyde detection. The fluorescence probe is synthesized from citric acid and urea as raw materials with a hydrothermal method, a prepared yellow carbon dot solution is oxidized into green or blue nitrogen-doped carbon dots, groups containing nitrogen and oxygen are located on surfaces of the nitrogen-doped carbondots, and average grain diameter of the nitrogen-doped carbon dots is smaller than 10 nm. The invention further provides a preparation method of the fluorescence probe. The fluorescence probe is synthesized from citric acid and urea as the raw materials with the hydrothermal method, the prepared nitrogen-doped carbon dot solution is yellow and is stirred for several hours to several days in an open beaker for oxidization, and a green or blue nitrogen-doped carbon dot solution is obtained. Fluorescence of the oxidized nitrogen-oxide-doped carbon dots is enhanced and fluorescence quenching occurs after the carbon dots act with formaldehyde, on the basis, an ultra-sensitive fluorescence method is established to be used for quantitative detection of formaldehyde, detection selectivity is good, and detection limit is low. The fluorescence probe can be stable in multiple metal ion solutions and has low cytotoxicity and good biocompatibility.

An electrochemical sensor for sensing a gaseous analyte includes a substrate having at least two electrodes disposed thereon, and a carbon nanotube-polyaniline (CNT / PANI) film disposed on the substrate and in contact with at least two electrodes. The CNT / PANI film includes carbon nanotubes coated with a thin layer of polyaniline. The thickness of the polyaniline coating is such that electron transport can occur along and / or between the carbon nanotubes.

The invention aims at providing a nano material for detecting dimethoate. The nano material comprises the following components by weight percent: 97.43 to 99.31 percent of sodium silicate, 0.06 to 0.23 percent of TPPS4 and 0.63 to 2.34 percent of plant-esterase. The plant-esterase is fixed by adopting a sol-gel technology, the fixation process is a physical embedding process, a gel network is gradually formed surrounding the enzyme, the structure completeness and isotropy and biological activity of surface microstructure of the enzyme can be maintained by virtue of the moderate reaction condition, amorphous structure of the gel and biological compatibility. Then the TPPS4 enters the gel network by virtue of the micropores on the surface of the gel to be reacted with the plant-esterase so as to form aggregation on the surface of the enzyme. In the gel network, the enzyme and the aggregation have less possibility of being subjected to the unfavorable influence of unfavorable environmental factors, but also the structure is more stable, the precipitate is unlikely to form, the enzyme and the aggregation are easy to store, the reaction activity can be well protected, and the detection reaction is favored.

The invention relates to an electro-polymerization preparation method of an electrochemical sensor for quickly detecting EGCG (Epigallocatechin-3-Gallate), and relates to a technology in the field of active ingredient analysis and detection of an agricultural product. The method mainly comprises the following steps of: pre-treating a glass-carbon electrode; performing electro-polymerization filming on the surface of the glass-carbon electrode; and eluting template molecules to obtain EGCG molecularly imprinted membrane modified electrode, wherein the sensor can be used for quick detection of an EGCG-containing actual sample in combination of an electrochemical working station. The electro-polymerization preparation method has the advantages of high selectivity, high operation efficiency, high stability of the sensor, capability of being recycled, low cost and suitability for quick, real-time and field detection, and is suitable for quick detection of the content of the main active ingredient EGCG in tea and products thereof and quality evaluation of the tea or the tea products.

The invention discloses a method for constructing a photoelectrochemical sensor based on perovskite and black zirconium dioxide to detect 5-hydroxymethylcytosine deoxyribonucleotide (5hmC). The photoelectrochemical sensor includes an electrode, and the electrode is sequentially decorated with perovskite, mercaptopropionic acid, 5hmC and black ZrO 2 . First, a perovskite-based photoelectrochemical biosensor was constructed, using perovskite Bi 4 TaO 8 Good photoelectric activity and stability of Cl, M.HhaI methyltransferase catalyzes the specific reaction of hydroxymethyl groups with sulfhydryl groups on 5hmC, and black ZrO 2 Specific recognition of phosphate groups via black ZrO 2 with Bi 4 TaO 8 Cl forms a heterojunction to promote the transfer of photogenerated electrons to enhance the photoelectric signal, achieving high sensitivity and high specificity detection of 5hmC. The detection method of the invention is simple, easy to operate and low in cost, not only expands the application range of the two nanometer materials, but also realizes the detection of 5hmC.

The invention relates to a preparation method and application of a sensing chip for detecting atrazine. A single-molecule alkyl chain layer is formed on a gold film of the surface plasma resonance sensing chip; atrazine molecularly imprinted polymer reaction solution is prepared by modifying the single-molecule alkyl chain layer; after soaking and eluting, holes which only respond to atrazine molecules are left in a molecularly imprinted polymer film, and the sensing chip for detecting the atrazin is obtained; when the sensing chip is used for detecting a sample by using the surface plasma resonance technology, the resonance angle changes after the sensing chip adsorbs the atrazine molecules in the sample, and the resonance angle change value and the sample concentration are in directly proportional linear relationship, so that the atrazine in the sample can be quantitatively detected on the basis of the change of the resonance angle. According to the preparation method and the application, the surface plasma resonance technology and the molecular imprinting technology are adopted to prepare the sensing chip, and the prepared sensing chip used for detecting the atrazine has the characteristics of sensitivity, rapidness, accuracy and simplicity.