89results about How to "Enables trace detection" patented technology

The invention relates to a silicon cantilever sensor, a preparation method and application thereof, and belongs to the field of micro-nano sensors. A porous silicon structure is formed in hydrofluoric acid solution nearby a free tail end of a cantilever through a selective anodic oxidation method. By using the increased specific surface structure of a porous silicon area, large amount of linear polymer or hyper-branched polymer sensitive molecules with silicon-oxygen head groups and specific tail groups for specificity identification are self-assembled on the inner wall of a silicon hole, and large amount of detected chemical molecules can be specifically captured to accumulate the capturing mass of larger detected substances. The silicon cantilever sensor has the advantages of simple structure, convenient manufacture and easy realization, and can be applied to trace chemical gas detection.

The invention relates to an electrochemical sensor based on a molecular engram and a preparation method and an application thereof. The electrochemical sensor based on the molecular engram comprises a working electrode, a reference electrode and a counter electrode, wherein the base electrode of the working electrode is a gold electrode; sulfonated graphene is modified on the surface of the gold electrode; after airing, polymerization is performed in an acid buffer solution containing o-phenylenediamine and dopamine till the oxidation peak current of the o-phenylenediamine falls to zero, and then dopamine is eluted in a sulfuric acid medium; and the reference electrode and the counter electrode are a saturated calomel electrode and a platinum wire electrode respectively. Under an optimal condition, a molecular engram sensor with molecule identifying performance is prepared by an appropriate eluting method, so that rapid analysis and detection of the dopamine are realized. The electrochemical sensor based on the molecular engram has the advantages of quick response, high selectivity, high sensitivity and the like on the molecular engram, the aim of identifying molecules is fulfilled, and detection of the dopamine in the presence of high-concentration ascorbic acid is realized.

A chemical preparation method for a CdTe quantum dot fluorescent probe for detecting a trace amount of paraquat comprises the step of modifying thioglycollic acid on the surface of the CdTe quantum dot fluorescent probe emitting a red emission spectrum band so as to enable the CdTe quantum dot fluorescent probe is provided with carboxyl functional groups on the surface. The preparation process comprises the following two specific steps: firstly, preparing a NaHTe solution; then, synthesizing CdTe quantum dots of which the surfaces are modified with thioglycollic acid, and adjusting the pH value to be 10-12 with KOH, so as to obtain the CdTe quantum dot fluorescent probe. According to the invention, carboxyl with negative charge on the surfaces of the CdTe quantum dots and target paraquat molecules with positive charge have the electrostatic interaction through the positive charge and negative charge, when the CdTe quantum dots and the paraquat approach to each other in space, the red spectrum band emitted by the CdTe quantum dot fluorescent probe can be absorbed by green target analyte paraquat modules through the fluorescence resonance energy transfer principle, and the detection of a trace amount of paraquat can be implemented through the utilization of the variation of the CdTe quantum dot fluorescence intensity.

The invention discloses a qualitative detection method for an illegal ingredient, i.e., Sudan red, in raw materials of feeds. According to the method, suspected areas are primarily screened through microscopic image processing, so a detection scope is reduced; then a microscopic Raman imaging spectrometer is used for detecting the Raman spectra of the suspected areas, the spectra are pretreated so as to obtain training samples, an IVISSA method sensitive to classes is used for waveband selection, and the IVISSA method can select characteristic peaks of Sudan red substantially different from characteristic peaks of other components, which enables detection efficiency and accuracy to be improved; the average spectrum of each training sample is taken and incorporated into a standard spectrum matching database; and the microscopic Raman spectrum of an unknown sample is acquired according to coordinates of detection points obtained in primary image election, then same spectral pretreatment is carried out, and a same wavelength variable is chose for one-to-one matching with each spectrum in the standard spectrum matching database according to a feature enhanced spectral angle matching method so as to determine whether the unknown sample contains Sudan red or not. The qualitative detection method has the advantages of rapid detection, good stability, and lower false positive rate and detection limits.

The invention provides a method for quantitatively detecting salbutamol by using CdTe quantum dots. The method comprises the following steps: uniformly mixing the CdTe quantum dots with surfaces modified by mercaptoacetic acid with a substance to be detected, namely salbutamol, in a phosphate buffer solution, and then detecting fluorescent strength of a system by adopting a molecular fluorometer to realize trace detection of salbutamol because that in a weakly alkaline solution system, the CdTe quantum dots with the surfaces modified with carboxyl groups having negative charges and target molecules having positive charges, namely salbutamol, form a new compound system through electrostatic interaction so as to cause fluorescence quenching. Detection results show that salbutamol has relatively high sensitivity and a relatively wide linear range against the fluorescence quenching of the CeTe quantum dots, so that the changes in the fluorescent strength of the CdTe quantum dots are used for realizing the quantitative detection of salbutamol; and furthermore, the method for quantitatively detecting salbutamol by using the CdTe quantum dots, provided by the invention, is very simple in experimental operation, the detection time is short and the analysis cost is low.

The invention discloses a dual-emission fluorescent probe and a method for simultaneously detecting nitrite ions and Hg<2+>, which belong to the technical field of environmental detection. The fluorescent probe is a compound formed by carbon quantum dots CQDs, Tb<3+> and 3-aminophenylboronic acid in a buffer solution system with the pH value of 7.0 to 8.0. The carbon quantum dots CQDs are preparedfrom a mixed aqueous solution of nicotinic acid and barbituric acid through a hydrothermal reaction. The detection method comprises the steps of quantitatively adding a to-be-detected solution into the buffer solution system for constant volume, and then scanning an emission spectrum of a fluorescence system in a wavelength range of 320 to 650nm by taking 260 to 280nm as an excitation wavelengthof the buffer solution after constant volume; and calculating the concentrations of Hg<2+> and NO2<-> in the to-be-detected solution according to the linear relationship between the fluorescence quenching efficiency at 373 nm and 545 nm and the concentration of a to-be-detected substance. The fluorescent probe provided by the invention not only can realize trace detection of NO2<-> and Hg<2+> in awater sample, but also has better consistency and selectivity in detection results compared with a spectrophotometric method.

The invention provides a fast sulfide ion test method. The method uses a property of ANS that the fluorescence of 4-Amino-1-Naphthalene sulfonate (ANS) can be effectively quenched by MnO2 nano-material to prepare the ANS/MnO2 composite system. When tiny portion of S<2-> is added in the system, because the oxidation-reduction reaction occurs between the S<2-> and MnO2 to generate divalent manganese ions in the solution, thus enhancing the fluorescence intensity of the ANS, and the increase of the fluorescence intensity is in a linear relationship with the S<2-> ions concentration, thus achieving the test of S<2-> ion. Compared with prior art the method has the advantages of being simple in operation and being able to test the S<2-> ion in a fast and real time mode.

The invention discloses a high-sensitivity food colorant detection method, which comprises the steps of dropping 10<-8>mol/L to 10<-3>mol/L of food colorant standard liquid on a flower-shaped nano silver particle SERS (Surface Enhanced Raman Scattering) substrate, and collecting a raman spectrogram and data of the food colorant standard liquid through a raman spectrometer; further adopting a principal component analysis method for processing the raman spectrum data of the food colorant standard liquid so as to obtain a raman spectrum intensity-food colorant concentration relational expression of the food colorant standard liquid; processing food to be detected into a solution, dropping the solution on the flower-shaped nano silver particle SERS substrate, collecting an SERS spectrogram and data of the food solution to be detected through the raman spectrometer, comparing with the SERS spectrogram of the food colorant standard liquid to obtain the attribute of a colorant in food to be detected, and obtaining the content of the colorant in the food to be detected through the SERS spectrum intensity-food colorant concentration relational expression of the food colorant standard liquid. The method can be used for detecting a trace colorant in the food, and is simple to operate.

The invention relates to a composite fluorescent biosensor, and a preparation method and an application thereof. The composite fluorescent biosensor comprises a graphene quantum dot and a carboxymethyl cellulose-chitosan polyelectrolyte microsphere; and the carboxymethyl cellulose-chitosan polyelectrolyte microsphere is a microsphere having a core-shell structure, the core is made of melamine andformaldehyde, and the shell is made of chitosan and carboxymethyl cellulose. The preparation method of the organic-inorganic composite fluorescent biosensor and a fluorescence detection method of target biological polysaccharides are helpful for improving other biological sensors. The composite fluorescent biosensor formed by cellulose ether-based polyelectrolyte microsphere induced graphene quantum dot aggregation has a very good market prospect and very good industrial production values.

The invention relates to a preparation method for an aptamer biosensor for T-2 toxin detection in food or feed and application, which belong to the technical field of electrochemical detection. The method is characterized by comprising steps: a gold nanorod (Au NRs) material is firstly synthesized and obtained; platinum is then reduced on the gold nanorods to form gold platinum nanorods (Au@PtNRs), through combination with reducing graphene oxide-tetraethylenepentamine (rGO-TEPA), increasing of an immobilization amount is realized, and the signal amplification ability is improved; then, through combination with single-stranded DNA signal probe, a biosignal probe is thus prepared; and finally, through fixing of molybdenum disulfide-polyaniline-chitin-gold nanoparticle composite material anda DNA capture probe, an aptamer biosensor for T-2 toxin detection is thus prepared. The sensor is successfully applied to trace detection of T-2 toxin in food or feed. The method has the advantages that the limitation of a T-2 toxin small molecule substance is broken through, and through introducing a nucleic acid aptamer, T-2 toxin high-sensitivity and high-specificity trace detection can be realized, and a simple and quick new strategy is provided for mycotoxin detection.

The invention discloses a method for measuring the dissolution amount of a PVA (Polyvinyl Alcohol) optical film, which comprises the following steps: soaking a PVA optical film to be measured in waterto prepare an extracting solution to be measured; taking a mixed solution of a boric acid solution and an iodine/potassium iodide solution as a chromogenic solution, adding the chromogenic solution into the to-be-detected extracting solution, then determining the absorbance, and obtaining the concentration of PVA in the to-be-detected extracting solution according to the standard relation curve of the absorbance and the concentration of PVA, thereby calculating the dissolution amount of the PVA optical film. According to the method, trace detection of PVA in the solution can be simply and efficiently realized, the dissolution amount of the PVA optical film can be quickly measured, and the method has guiding significance for evaluating the product quality of the PVA optical film.

The invention relates to a super-hydrophobic surface reinforced Raman substrate prepared from a silicon nanometer dielectric material and a preparation method thereof. The substrate is formed by a silicon micron cone integrated with metal nanoparticles and a cascade structure formed by nanowires. The preparation method of the structure comprises the following steps that S1, a silicon wafer is put into a micromolecule alcohol and strong base mixed solution; the silicon micron cone structure is built through water bath heating; S2, the silicon micron cone structure is put into mixed corrosion liquid of silver salt solution and HF solution; etching is performed to obtain a silicon micron/nanometer cascade structure; S3, the silicon micron/nanometer cascade structure obtained in the S2 is soaked by acid solution so as to remove silver nanoparticles remained at the surface; then, the silicon micron/nanometer cascade structure is subjected to gold nanoparticle wrapping covering; S4, low-surface-energy substances are used for performing surface covering modification on the gold-silicon composite structure obtained in the S3, i.e., the super-hydrophobic surface reinforced Raman substrate is obtained. The super-hydrophobic surface reinforced Raman substrate provided by the invention has super-hydrophobic property; the static contact angle with water is 160 to 162 degrees.

The invention discloses a sulfide ion detection method based on a Ce(III)/AgNCs composite nano cluster material. Ce(III) ions can effectively enhance fluorescence emission of AgNCs, so as to form a Ce(III)/AgNCs composite system. When a trace of S<2-> is added to the system, S<2-> reacts with Ag atoms in the Ce(III)/AgNCs composite system, consequently, an original structure of the Ce(III)/AgNCs composite system is damaged, then the fluorescence strength of the Ce(III)/AgNCs composite system is eliminated, the eliminated fluorescence strength and concentration of S<2-> ions are in a linear relationship, so that the S<2-> ion detection method is created. The method is easy to operate, and can detect a trace of S<2-> rapidly in real time.

The invention discloses a water body polycyclic aromatic hydrocarbon detection reagent. The detection reagent consists of a reagent A and a reagent B, wherein the reagent A is an aqueous solution of a graphene/nano precious metal compound, and the reagent B is a surfactant solution. The invention also discloses an application of the water body polycyclic aromatic hydrocarbon detection reagent. The application comprises the steps of: firstly dispersing the reagent B in a polycyclic aromatic hydrocarbon solution; then adding the reagent A into the mixed solution and evenly mixing; and finally performing Raman detection on a suitable amount of the mixed solution to obtain a polycyclic aromatic hydrocarbon SERS (Surface Enhanced Raman Scattering) spectrum. The invention provides the water body polycyclic aromatic hydrocarbon detection reagent and the application thereof which can be used for rapidly detecting polycyclic aromatic hydrocarbons in a water body, are convenient to detect and good in data repeatability, and can realize the single-component or multi-component detection of the polycyclic aromatic hydrocarbons.

The invention discloses an on-line measuring system and a measuring method for concentration of nitrous acid and nitrous acid. The system comprises an external sample feeding unit, a liquid phase chemical conversion unit and an optical absorption detection unit which are connected in sequence, wherein the external sample feeding unit is used for feeding a sample of a nitrogen-containing compound; the liquid phase chemical conversion unit is used for absorbing and converting the liquid phase chemical conversion unit from the external sample feeding unit into nitrite; and the optical absorption detection unit is used for converting the nitrite from the liquid phase chemical conversion unit into an ultraviolet-visible absorbent material, and used for implementing optical detection. By adopting the system, simultaneous measurement of the nitrous acid and the nitric acid can be achieved, and furthermore interference of other gaseous phase substances can be eliminated through parallel channels. By adopting the system, trace detection on the nitrous acid and the nitric acid in the atmosphere can be achieved, and trace detection on the nitrous acid and the nitric acid in water bodies is also achieved, the detection sensitivity is greater than 10pptv and 0.03mu g/L, the response time is less than 3-5 minutes, and the system can be applied to atmospheric environments, water body environment monitoring, experimental scientific research and the like.

The invention discloses a heparin detection method for a copper nano-cluster based on a denatured bovine serum protein as template. The method comprises the following steps: forming a heparin detection system with a phosphoric acid buffer aqueous solution, a copper nano-cluster dispersion system and a to-be-tested sample; detecting fluorescence intensity change before and after adding the to-be-tested sample; and comparing with a standard curve to obtain the content of heparin in the to-be-tested sample. The method synthesizes the copper nano-cluster by taking the denatured bovine serum protein as the template by means of a one-pot method. The synthesized material is uniform in particle size, good in fluorescence property and stable in property, and the light-emitting position is near 642.04 nm and belongs to a near infrared area, so that interference of autofluorescence is avoided. The method can detect the heparin content directly and quickly, is wide in detection linear range and low in detection limit and has a very good application prospect in the fields of biological system detection, clinical applications and the like.

The invention provides a preparation method and an application of a fluorescence sensor for detecting ochratoxin A. A quantum dot-nano porphyrin fluorescence 'on-off' sensor is formed with a water-soluble ZnCdSe quantum dot as a fluorescent probe and self-assembled nano porphyrin, which is prepared from a tetra-(4-pyridyl)-zincporphyrin-N,N-dimethylformamide solution and dodecyl dimethyl betaine,as a quantum dot fluorescence quencher. The OTA is combined with nano porphyrin to release quantum dots, so that the fluorescence of the quantum dots is recovered, and the quantum dot-nano porphyrin fluorescence "on-off-on" sensor is formed. The addition of other mycotoxins does not cause the change of the fluorescence intensity of the system. The fluorescence sensor realizes high-selectivity detection of OTA, effectively amplifies signals, obtains high-sensitivity and strong-specificity detection results, does not need to depend on expensive large instruments, and is simple in pretreatment and rapid in detection.

The invention relates to a method for detecting aflatoxin M1. According to the method, aflatoxin B1 marked by enzyme is taken as a competitive antigen, and on the basis of a dynamic light scattering technology, the aflatoxin M1 is detected through a direct competitive enzyme linked immunoassay analysis method. The method reduces the affinity between the competitive antigen and a monoclonal antibody of the aflatoxin M1, and the problem is solved that the sensitivity is reduced due to the fact that the competitive antigen is not easily competed by s target competitive antigen; the detection of an output signal is performed by means of the dynamic light scattering method, compared with a traditional direct competitive enzyme linked immunoassay analysis method, the detection sensitivity can beimproved, and the trace detection of the aflatoxin M1 can be achieved.

The invention discloses an electrochemical sensor electrode surface nano-material modification method and a sensor. Carbon paper is used as a working electrode substrate; graphene nano, thionine and nano gold are modified on the surface of a working electrode to form a composite biosensitive membrane; and a specific antibody is fixed to the biosensitive membrane, and antigen detection is realizedby utilizing that the antigen concentration is proportional to the reduction degree of the reaction current. The multilayer nano sensitive membrane sensor can realize trace detection of high-sensitivity cancer protein and polypeptide molecules.