212 results about "Fluorescence sensor" patented technology

The invention provides a flexible fluorescence sensor as well as a preparation method and application thereof. The flexible fluorescence sensor comprises TCTG particles and dual-network hydrogel, the TCTG particles are distributed in network pores of the dual-network hydrogel to form functional gel, the TCTG particles are formed by Ti3C2TxMXene nanosheets and graphene quantum dots, the dual-network hydrogel is formed by acrylamide and sodium carboxymethyl cellulose, and the TCTG particles are distributed in the network pores of the dual-network hydrogel to form functional gel. The functional gel is soaked in a hydrochloric acid glycol solution for treatment. The flexible fluorescence sensor provided by the invention can integrate the structural advantages of all the components, so that a synergistic coupling effect is possibly generated, a fluorescence detection function with excellent mechanical strength, frost resistance and high sensitivity is integrated into a multifunctional system, the food spoilage condition can be reliably monitored in real time under a harsh environmental condition, and the application prospect is wide. And health and economic risks caused by occupational exposure and environmental emission in an aquatic product supply chain are solved.

The invention discloses a method for constructing a dual-mode sensor through smartphone-assisted surface molecular imprinting for detecting diphenyl phosphate and application of the dual-mode sensor, and belongs to the technical fields of biochemical analysis, functional nano materials and life science. In synthesis, solubility and selectivity of a target object and photo-initiation efficiency in a polymerization process are optimized, and diphenyl phosphate molecularly imprinted nano-enzyme MIPs is rapidly prepared through a molecular imprinting technology; in the detection, H2O2 and 3, 3, 5, 5-tetramethyl benzidine TMB are catalyzed by peroxidase-like activity of Fe and N-CDs to generate a chromogenic reaction and an inner filter effect of oxTMB is used for inhibiting a fluorescence signal, dual-signal cross validation is realized in cooperation with a smart phone, and the colorimetric-fluorescence sensor for detecting diphenyl phosphate is constructed. The sensor has specific recognition selectivity and binding affinity of diphenyl phosphate, is simple to operate and low in cost, can realize sensitive detection of diphenyl phosphate in a wide linear range, has the detection limit as low as 16 pg / mL, and is suitable for field analysis of trace DPhP in a complex water environment.

The invention discloses a dual-emission molecular imprinting ratiometric fluorescence sensor, a preparation method thereof and application of the dual-emission molecular imprinting ratiometric fluorescence sensor in aureomycin detection, and belongs to the technical field of chemical sensors. The preparation method of the sensor comprises the following steps: preparing silicon dioxide-quantum dot composite nanoparticles, and preparing a molecularly imprinted polymer by taking salicylamide as a template molecule; and mixing the molecularly imprinted polymer and the silicon dioxide-quantum dot composite nanoparticles in an HEPES buffer solution by adopting a post-mixing strategy to construct the dual-emission molecularly imprinted ratiometric fluorescence sensor. The double-emission molecular imprinting ratiometric fluorescence sensor has the beneficial effects that the double-emission molecular imprinting ratiometric fluorescence sensor provided by the invention is rich in fluorescence color change, rapid, high-sensitivity and visual detection of aureomycin can be realized, the whole detection process is simple, convenient and rapid, and the double-emission molecular imprinting ratiometric fluorescence sensor is suitable for being widely popularized in practical application.

A pig for use in a pipeline is provided for determining the material of the pipeline in the context of an inline inspection. The pig includes a position determination unit and at least one braking arrangement for immobilizing the pig at a certain position in the pipeline. The pig also includes an X-ray fluorescence sensor.

The invention designs a preparation method of a magnetic molecular imprinting-aptamer sandwich fluorescence sensor for detecting kanamycin. And the magnetic molecular imprinting composite material Fe3O4 (at) UiO-66 (at) MIP with a specific adsorption target object KANA is prepared. When a detection target object KANA exists, the Fe3O4-coated UiO-66-coated MIP can rapidly and specifically capture the KANA in a short time. Then, a DNA single-stranded aptamer marked with FAM is added, after the aptamer and KANA captured on the surface of the Fe3O4 at-UiO-66 at-MIP are subjected to specific recognition and magnetic separation again, an aptamer probe can enter sediment along with the magnetic composite material Fe3O4 at-UiO-66 at-MIP, the fluorescence intensity of supernate is reduced, and quantitative analysis is conducted according to the fluorescence difference value delta F. When the KANA does not exist, the aptamer cannot enter the precipitate, so that the fluorescence signal intensity is not changed. Double recognition is formed through specific binding of an MIP imprinting cavity and the aptamer, matrix interference is reduced by means of fluorescence characteristics and magnetic separation capacity, the method has the advantages of being high in adsorption capacity, specific in recognition, high in sensitivity, wide in detection range, good in selectivity and the like, and rapid and accurate detection of KANA in a complex sample can be achieved.

The invention relates to the field of veterinary drug residue detection, in particular to a fluorescence sensor based on DNA molecular machine mediated split Cas12a and application of the fluorescence sensor to ofloxacin detection, the fluorescence sensor comprises a system A, a system B and a system C. According to the final concentration of each system, the system A comprises an AP / CP double-stranded compound and a 20 mM Tris-HCl buffer solution 1, the system B comprises a double-stranded compound, an sRNA probe and a 10 mM Tris-HCl buffer solution 2, and the system C comprises a DNA molecular machine mediated split Cas12a. The system C comprises a Cas12a / hRNA compound, a pDNA / psG43 signal probe, ThT and a 20 mM Tris-HCl buffer solution; aP in the AP / CP double-chain compound is an aptamer of ofloxacin, and AP and CP in the AP / CP double-chain compound are paired and connected through complementary base pairing; the sequences of AP, CP, PS, SS, sRNA, hRNA, pDNA and psG43 are respectively as shown in SEQ ID NO.1-SEQ ID NO.8. The invention also discloses a kit for detecting the content of the protein. According to the application, the nucleic acid aptamer of ofloxacin is utilized, based on a DNA molecular machine and SCas12a as a signal amplification technology and sulfo-modified G43 as a fluorescent signal probe, even if the content of ofloxacin in a sample is extremely low, detection can be accurately realized.

The invention discloses nitrogen-doped carbon quantum dots derived from American cockroach dregs as well as a preparation method and application of the nitrogen-doped carbon quantum dots, and belongs to the technical field of nitrogen-doped carbon quantum dots. The nitrogen-doped carbon quantum dots are prepared from the American cockroach dregs by a one-step hydrothermal method, optimal synthesis parameters are obtained through experimental optimization of synthesis conditions, and the prepared nitrogen-doped carbon quantum dots have excellent optical characteristics and stability; the invention also provides an application of the nitrogen-doped carbon quantum dot in Ag < + > detection, the nitrogen-doped carbon quantum dot has good selectivity, sensitivity and anti-interference performance on Ag < + >, a detection mechanism is an internal filtering effect and light-induced electron transfer, and the nitrogen-doped carbon quantum dot can be used as a preferred fluorescent material of an Ag < + > fluorescent sensor. The nitrogen-doped carbon quantum dots synthesized by the method not only have an Ag < + > sensing function, but also realize high-valued utilization of medicine residues, and also provide a new thought for self-doping of heteroatoms.

The invention relates to the technical field of biomedical detection, and discloses a portable urine component detection system and method based on a fluorescence sensor array. The system comprises a fluorescence sensor array, different fluorescence probes are used for detecting different trace components in urine, and fluorescence color gradient changes are generated through a probe-target object reaction, so that bilirubin, glucose and albumin in the urine are detected. The detection system comprises a micro-fluidic chip which integrates a capillary driving channel and a colorimetric reaction area and is used for sample transmission and reaction area positioning; an ultraviolet excitation light source and a multi-angle optical sensor are arranged in the camera obscura type color acquisition module, and the camera obscura type color acquisition module eliminates ambient light interference and captures fluorescence chromaticity signals; and the intelligent data processing system is integrated with an intelligent analysis end of the smart phone, establishes a quantitative relationship between chromaticity parameters (RGB and hue saturation) and the concentration of a target object through a machine learning model, and outputs a detection result in combination with an ambient light correction algorithm.

The application provides a fluorescent sensor based on a tripod [5] arene, which is obtained by self-assembly complexation of a host of a tripod [5] arene TP5 and a guest of a quaternary ammonium salt in an H2O-DMSO system. A supramolecular system is constructed by host-guest interaction between the tripod [5] arene TP5 and the amphiphilic guest TPN, and then PbS fluorescent nanoparticles are generated in situ under ion induction. Fluorescence enhancement and high-sensitivity detection (LOD=7.00*10 2+ -6 M) of Pb ‑8 are realized. In addition, the fluorescent supramolecular polymer network based on the PbS fluorescent nanoparticles can be successfully applied to in-situ detection of Pb 2+ in cells.

The invention discloses a preparation method of a portable paper-based ratiometric fluorescence sensor APBA-CsPbBr3 at-UiO-66 / Ru, which comprises the following steps: 1, adding lead bromide and cesium bromide into N, N-dimethylformamide, then adding 5-bromovaleric acid and an oleylamine ligand, and stirring; 2, perfluorooctyltriethoxysilane is added, and a precursor solution is obtained; 3, adding zirconium chloride and terephthalic acid into N, N-dimethylformamide to obtain a homogeneous solution; 4, after heating, UiO-66 is obtained; 5, stirring the precursor solution, APBA, UiO-66 and tris (2, 2-dipyridyl) ruthenium chloride hexahydrate to obtain a composite material; and 6, dropwise adding the composite material solution into the filter paper. The APBA modified material is adopted as a recognition unit, the APBA modified material and the paper base construct a fluorescence sensing platform, visual quantitative analysis of oxytetracycline in water is achieved, and the device is convenient to carry, low in detection limit, high in anti-interference performance, easy and convenient to operate and suitable for on-site rapid detection of oxytetracycline.

This invention belongs to the field of fiber optic sensing and relates to a method based on WS 2 A temperature sensor based on all-fiber fluorescence intensity comprises a single-mode fiber, a three-hole grapefruit fiber, and a multimode fiber connected in sequence; the three-hole grapefruit fiber has three air holes, in which WS is deposited. 2 The multimode fiber output end is equipped with a mounting base, on which a filter is mounted. This invention utilizes WS... 2 Assembled within a three-hole optical fiber, with single-mode and multi-mode fibers fused together at both ends, this sealed structure effectively isolates the sensor from external air, preventing contact between the outside air and the two-dimensional material on the inner wall of the fiber during heating. This slows down the decomposition of transition metal sulfides, significantly improving the fluorescent sensor's ability to detect high temperatures and extending its lifespan. The sensor itself and its detection system are coupled and output via optical fiber, eliminating the need for external spatial light or optical modulation.

The application discloses a three-channel fluorescence sensor array based on sulfur quantum dots and a preparation method and detection application thereof. The sensor array is composed of three kinds of sulfur quantum dots, namely C-SQDs, PSS-SQDs and beta-SQDs. When target objects exist, the three kinds of sensing units generate differentiated fluorescence responses, forming a unique "fingerprint map". By using principal component analysis to analyze the response mode, the array can successfully distinguish between structurally similar baicalein, fiscetin, myricetin, quercetin and rutin in a concentration range of 8.0-56 muM. In addition, the array can also perform semi-quantitative analysis on a single flavone compound in a range of 4.0-56 muM, and the first principal component has a good linear relationship with the logarithm of the concentration of the target object.

This invention discloses a method to avoid the influence of cations on carbon nanotube fluorescent sensors, and a gel-based dopamine sensor based on Al-(AT)15-SWCNTs complex and its application. The method to avoid the influence of cations on carbon nanotube fluorescent sensors first involves preparing a single-stranded DNA sequence (AT). 15 Modified single-walled carbon nanotube solution ((AT) 15 -SWCNTs); then (AT) 15 The SWCNTs solution and agarose gel were mixed at a 1:1 volume ratio and allowed to settle at (AT). 15 -SWCNTs solidify to obtain a gel-based dopamine sensor; the gel-based dopamine sensor is placed in an Al(NO₃)₃ solution for at least one hour, and then washed by immersing it in an HCl solution with pH ≤ 3.7 to remove residual free Al from the gel. 3+ The ions ultimately yield Al−(AT). 15 A gel-based dopamine sensor for ssDNA-SWCNT complexes. Trivalent aluminum ions pre-occupy the interaction sites of phosphate groups to prevent further interactions between other cations and phosphate groups. Agarose gel-based ssDNA-SWCNTs avoid cation-induced aggregation.

本发明公开了一种基于静电驱动的双酶级联放大荧光传感器及其制备方法和应用，所述纳米酶荧光传感器由探针Azo‑Bodipy 685、胆碱氧化酶（CHO）和氯化乙酰胆碱（ACh）组成。本发明基于静电吸附原理，提出静电络合共固定化‑酶级联反应协同策略，构建一种新的静电驱动荧光传感器，利用ACh的季铵盐正电荷与CHO表面负电荷的静电作用，在特异性荧光探针Azo‑Bodipy 685表面构建纳米尺度空间限域的酶反应微环境。当有机磷农药抑制乙酰胆碱酯酶（AChE）时，氯化胆碱生成减少导致CHO催化产生的过氧化氢量下降，荧光信号强度减弱，一系列荧光强度的变化可以实现检测AChE活性和测定有机磷农药残留含量。

The application discloses a method for imaging magnesium ions in living cells based on chemically modified deoxyribozyme, and belongs to the technical field of metal ion imaging. The method comprises the following steps: chemically modifying deoxyribozyme 10-23, screening and obtaining deoxyribozyme 10-23 (CaBn) which is modified with carboxyl (Ca) at the 8th position of the catalytic ring and benzene ring (Bn) at the 12th position; performing biochemical characterization and comparison; constructing a fluorescence sensor responding to magnesium ions; characterizing the performance; and applying the fluorescence sensor to imaging magnesium ions in living cells. Compared with the wild type, the application can catalyze the cleavage reaction under the condition of lower concentration of magnesium ions; therefore, the fluorescence sensor constructed from the deoxyribozyme can more effectively respond to lower concentration of magnesium ions in vitro, and the detection limit reaches 0.03 mM; in addition, the fluorescence sensor can perform fluorescence imaging on endogenous magnesium ions in living cells, and provides a new molecular tool for the field of molecular biology.

The application provides a preparation method and application of a near-infrared two-region fluorescent sensor, and chiral single-walled carbon nanotubes are separated by using a double water phase extraction method; materials in the separation process include deionized water, polyethylene glycol, dextran, sodium dodecyl sulfate, sodium deoxycholate and cholic acid sodium hydrate; the chiral single-walled carbon nanotubes are dispersed and mixed with 4-nitrobenzene tetrafluoroboric acid diazonium salt to obtain the fluorescent sensor; high-purity (6,5)-SWCNT is efficiently and simply separated by using the double water phase extraction technology, the prepared SWCNT-NBD nanomaterial has good optical performance, including bright light emission in the near-infrared two-region, has good penetration capacity on biological tissues, the fluorescent detector (SWCNT-NBD) has low detection line, wide linear range, good selectivity on DA, and is convenient to prepare and low in cost.

This invention relates to the field of medical detection technology and discloses a fluorescent sensor for high-sensitivity detection of circRNA and its detection method based on machine learning. The sensor includes a splitting probe M, a splitting probe N, a circular template T, a probe CrRNA, and a reporter gene. The 5' end of probe M is modified with a phosphate group, and the 5' end of probe M and the 3' end of probe N each have 15 nucleotides complementary to the target. The single-stranded DNA of splitting probe M and the single-stranded DNA of splitting probe N are ligated into the single-stranded DNA of probe MN in the presence of the target. The 5' end of the circular template T is modified with a phosphate group, and probe T, from its 5' end to its 3' end, consists of the N probe complementary region, the functional region, and the M probe complementary region, respectively. The CrRNA probe, from its 5' end to its 3' end, consists of the protein-binding region and the functional complementary region, respectively. The 5' end of the reporter gene is modified with a fluorescent group, and the 3' end is modified with a quenching group, which quenches the fluorescence signal of the 5' end fluorescent group.

The invention relates to a preparation method of a fluorescence sensor. The invention relates to a preparation method of a portable pesticide detection fluorescence sensor of silver nanocluster (AgNCs) at zeolite imidazolate skeleton (ZIF) at polydopamine (PDA) and application of the portable pesticide detection fluorescence sensor in on-site rapid detection of 2, 4-dichlorophenoxyacetic acid (2, 4-D), and belongs to the technical field of fluorescence sensors. The method comprises the following steps: wrapping AgNCs with ZIF, and modifying the surface of the AgNCs with dopamine to form an AgNCs-ZIF-PDA composite material with high stability, high fluorescence enhancement, high enzyme responsiveness and high controllability; then, the material is integrated into a nano clay-acrylamide hydrogel matrix with high fitness, and a sensor with an adjustable shape is constructed. The sensor can be adaptively attached to the surface of a plant and is used for long-term in-situ monitoring of 2, 4-D pesticide. And in combination with an image processing algorithm, the system realizes accurate tracking of the tomato plant surface 2, 4-D degradation process, and the detection limit reaches 23.3 ng / mL. According to the invention, non-intrusive and low-cost technical support is provided for crop health management and sustainable precision agriculture.

This invention discloses a dual-emission molecularly imprinted ratiometric fluorescence sensor, its preparation method, and its application in the detection of chlortetracycline, belonging to the field of chemical sensor technology. The preparation method of this sensor includes the following steps: preparing silica-quantum dot composite nanoparticles; preparing a molecularly imprinted polymer using salicylamide as a template molecule; and using a post-mixing strategy to mix the molecularly imprinted polymer and silica-quantum dot composite nanoparticles in HEPES buffer to construct the dual-emission molecularly imprinted ratiometric fluorescence sensor. The advantages of this invention are: the dual-emission molecularly imprinted ratiometric fluorescence sensor provided by this invention exhibits rich fluorescence color changes, enabling rapid, highly sensitive, and visual detection of chlortetracycline; and the entire detection process is simple, convenient, and fast, making it suitable for widespread application in practical applications.

The invention provides a preparation method and application of a fluorescence sensor for detecting metal ions based on a metal organic framework packaged nano-cluster. The preparation method comprises the following steps: by taking flexible fibers as a base material, firstly coating the surface of the flexible fibers with a metal organic framework, and then soaking the flexible fibers coated with the metal organic framework in a polyethyleneimine-terminated nano-cluster solution, thereby obtaining the metal ion detection fluorescent sensor based on the nano-cluster packaged by the metal organic framework. The polyethyleneimine is utilized to improve the stability and the fluorescence property of the nano-cluster obtained by reduction, so that the fluorescence sensor can maintain the fluorescence property under different pH values and temperature conditions. The prepared fluorescence sensor can rapidly respond to existence of target ions, fluorescence signals change obviously and rapidly, toxicity is small, reproducibility is good, the lower detection limit is low, fluorescence quenching is conducted on metal ions, and sensitivity is high.

The application belongs to the field of coordination chemistry and analytical sensing technology, and particularly relates to a Zn(II)-Tb(III) complex ratio fluorescence sensor and a preparation method and application thereof. The sensor is a double-metal coordination polymer formed by coordination of Zn(II) ions, Tb(III) ions, nitrogen-containing organic ligands and carboxylic acid organic ligands. Under excitation conditions, the sensor simultaneously generates an emission signal of ligand coordination with Zn(II) and a characteristic emission signal of Tb(III) ions, forming intrinsic double emission. By monitoring the fluorescence intensity ratio (I395 / I549) of the two characteristic emission peaks at 395 nm and 549 nm, ratio fluorescence detection of propyl gallate can be realized, and the detection limit is as low as 0.35 μM. The sensor of the application has a simple synthesis method, a rapid detection process, and realizes internal calibration by using a ratio signal, has strong anti-interference ability, and is suitable for detection of propyl gallate in edible oil and other actual samples.

The sensors (4) can be used to detect the concentration of an analyte, such as an electrolyte and / or a blood gas. In some models, these sensors may include a matrix material, a nanoparticle (2) associated with the matrix material, and a signaling molecule (10, 12, 14, 16) associated with the nanoparticle. In some cases, the signaling molecule may exhibit a fluorescence emission intensity (20, 22, 24, 26) as a function of the analyte concentration. Abbreviated figure: Fig. 2.

The invention belongs to the technical field of biosensing detection, and particularly discloses a label-free ratio fluorescence sensor and application thereof in quinine detection. The label-free ratio fluorescent aptamer sensor takes isothiocyanate as an internal reference signal and a fluorescent dye as a detection signal, and is obtained by mixing and incubating a quinine specific nucleic acid aptamer, a triphenylmethane fluorescent dye and isothiocyanate in a buffer solution. According to the invention, isothiocyanate is introduced as an internal reference signal, triphenylmethane dye is selected as a target response fluorescence signal molecule, and the quinine is detected by using the obvious fluorescence change of the target response fluorescence signal molecule in the binding-dissociation process of the target response fluorescence signal molecule and a quinine specific nucleic acid aptamer. The label-free ratio fluorescence sensor has excellent selectivity and stability, can be widely applied to the fields of food safety supervision, drug quality control, environmental water quality detection and the like, and is particularly suitable for rapid detection and emergency monitoring of quinine under the condition of limited resources.

The present application relates to the technical field of organic synthesis, and particularly relates to a zinc-based fluorescent probe containing a pyridyl carboxylic acid type component, and a preparation method and application thereof. 22 H 14 N3O2)(CHO2)(H2O)·C3H7NO·3H2O; the zinc-based fluorescent probe containing the pyridyl carboxylic acid type component belongs to a monoclinic system, and a space group is P 2 1 / c ; cell parameters are a = 7.2925(2) Å, b = 26.6839(8) Å, c = 12.8618(4) Å, α = 90°, β = 105.5770(10)°, gamma = 90°. The zinc-based fluorescent probe has good thermal stability and large light emission intensity, the preparation method is simple, and the zinc-based fluorescent probe can be used as a fluorescent sensor to detect Fe 3+ and 2,4,6-trinitrophenol in a DMF solution with high sensitivity and high selectivity.

The invention discloses a label-free ratio fluorescence sensor and a method for detecting fentanyl substances, and belongs to the field of analysis and detection.The sensor comprises a recognition element, the recognition element comprises six kinds of guanine-rich DNA aptamers and a signal conversion element, and the signal conversion element comprises a fluorescent dye. According to the invention, a plurality of fentanyl analogues can be rapidly detected.

This invention discloses a method and application for constructing a dual-mode sensor for detecting diphenyl phosphate using smartphone-assisted surface molecular imprinting, belonging to the fields of biochemical analysis, functional nanomaterials, and life science technology. In the synthesis process, the solubility, selectivity, and photoinitiation efficiency of the target analyte during polymerization are optimized, and molecularly imprinted nanozymes (MIPs) for diphenyl phosphate are rapidly prepared using molecular imprinting technology. In the detection process, the peroxidase-like activity of Fe,N-CDs catalyzes the colorimetric reaction between H₂O₂ and 3,3,5,5-tetramethylbenzidine (TMB), and the internal filtering effect of oxTMB suppresses the fluorescence signal. Combined with a smartphone, dual-signal cross-validation is achieved, constructing a colorimetric-fluorescence sensor for detecting diphenyl phosphate. This sensor exhibits specific recognition selectivity and binding affinity for diphenyl phosphate, is simple to operate, and low in cost. It can achieve sensitive detection of diphenyl phosphate over a wide linear range, with a detection limit as low as 16 pg / mL, making it suitable for on-site analysis of trace DPH in complex aquatic environments.

The invention relates to a diagnostic method for determining the oil quality of an engine oil for an internal combustion engine (2) of a vehicle, wherein the engine oil is or is made with a fluorescent dye, and wherein the internal combustion engine (2) is located in an engine oil circuit (1) in which a detector (6), in particular an LED-based fluorescence sensor, is arranged for detecting a fluorescence intensity, comprising the steps: - if an engine oil change has been detected, an oil quality test routine is started in which the fluorescence intensity is recorded with the detector (6) and stored as the initial intensity value, - repeated, in particular continuous or regular, measurement of the fluorescence intensity of the engine oil as the current intensity value, and - if a determined current intensity value is less than or equal to approximately 10 percent of the initial intensity value, a message is issued indicating that an engine oil change is required.

The application provides a preparation method of a ratio fluorescent aptamer sensor for detecting streptomycin in milk, and belongs to the field of food safety detection. The application comprises screening of streptomycin (STR) specific aptamer and construction of a ratio fluorescent sensor. The STR aptamer (Apt) is obtained by using a magnetic graphene oxide screening technology for the first time, the binding site is analyzed according to the secondary structure and molecular docking analysis, and the Apt52 with the best affinity to the target is obtained by truncation. The carbon quantum dots (CQDs) modified by the Apt52 are used as a reference signal, the AgNCs-SMP@ZIF-8 is used as a response signal to construct a fluorescent sensing method for judging whether the streptomycin is contained in the sample to be detected. The specific binding of the aptamer to the target causes the AgNCs-SMP@ZIF-8 to expose and quickly adsorb a large amount of Cu 2+ The fluorescence signal of the AgNCs-SMP@ZIF-8 is quenched, and the fluorescence signal of the CQDs always remains stable, and the streptomycin residue is detected by the fluorescence signal ratio change of the AgNCs-SMP@ZIF-8 and the CQDs. The detection limit of the sensor for the STR is 0.978 nM, and the sensor has satisfactory specificity and sensitivity.

The application belongs to the technical field of chemical analysis and detection, and discloses a zinc oxide quantum dot fluorescent sensor and application of the zinc oxide quantum dot fluorescent sensor in detection of kaempferol. The zinc oxide quantum dot fluorescent sensor is prepared by stirring zinc salt solution and lye uniformly, then adding amino silane and water to carry out sol-gel reaction to prepare a ZnO-QDs fluorescent probe solution; then, a substrate is immersed in the ZnO-QDs fluorescent probe solution to carry out incubation, and drying is carried out to obtain the zinc oxide quantum dot fluorescent sensor. S The zinc oxide quantum dot fluorescent sensor is applied to detection of kaempferol, can produce specific response with kaempferol, makes the fluorescence intensity of the ZnO-QD fluorescent probe gradually increase with the increase of the concentration of kaempferol, and can effectively exclude the interference of structural analogs such as quercetin and luteolin, so that the kaempferol in the sample can be accurately quantified; and the detection cost is low, the operation is convenient, the detection efficiency is high, the detection is green and safe, and the zinc oxide quantum dot fluorescent sensor is suitable for popularization and application.

The invention relates to the technical field of analytical chemistry, and discloses a ratio-dependent fluorescence sensor based on FRET effect for detecting patulin, the ratio-dependent fluorescence sensor comprises: an N, S-GQDs (at) apt fluorescence probe; a gold nanocluster solution with a concentration range of 20-70 [mu] g / mL; a metal organic framework solution with a concentration range of 5-30 [mu] g / mL; wherein the N, S-GQDs (at) apt fluorescent probe is prepared by mixing a patulin aptamer solution and a nitrogen and sulfur doped graphene quantum dot solution with the concentration range of 25-100 [mu] g / mL according to the volume ratio of 1: 2. The nitrogen and sulfur doped graphene quantum dots and a metal organic framework are creatively constructed into a fluorescence resonance energy transfer pair, the surface of the energy donor nitrogen and sulfur doped graphene quantum dots is modified with an aptamer, the detection limit of 3.29 pg / mL for patulin is obtained, and extremely high detection sensitivity is achieved.