107results about How to "Reduce matrix interference" patented technology

The invention discloses a determination method of residual amount of glufosinate, glyphosate and aminomethyl phosphoric acid in food. The determination method of residual amount of glufosinate, glyphosate and aminomethyl phosphoric acid in food comprises the following steps: in the sample pretreatment, firstly, extracting glufosinate, glyphosate and aminomethyl phosphoric acid in a food sample by a methanol water solution in sample pretreatment; then purifying an extracting solution by selecting a C18 dispersive solid-phase extraction agent; and finally, filtering, deriving, and determining three compounds qualitatively and quantitatively synchronously by combining with high performance liquid chromatography-tandem mass spectrum. According to the method provided by the invention, the operation is simple and convenient, and the reproducibility is good, and impurities in a sample extraction solution can be removed effectively; the pretreatment is the supplement and improvement of the existing QuEChERS method; the recycling rate can reach 70.5%-91.2%; the relative standard deviation is 4.5%-7.83%; the limit of quantification is 50micro-g / kg; the determination method can completely meet the technical requirement on safety detection of China, European Union, America and Japan, and can provide powerful technical support for food safety and export trade healthy development for people of China.

The invention belongs to the environmental protection and water treatment technical field, and discloses a method for determining trace nitrogen-containing disinfection by-product dimethyl nitrosamine in water. The method comprises the following steps 1) acidifying and pretreating a sample; 2) acidifying, drying and filling a solid phase extraction material; 3) controlling a solid phase extraction process, eluting and purifying an eluate; 4) naturally volatilizing the sample and controlling with constant volume; 5) using a liquid chromatography-mass spectrometry for analyzing dimethyl nitrosamine to obtain the determination result. Compared with the current international test methods, the method of the invention has the characteristics of rapidity, simpleness, little application amount of the poisonous and harmful organic solvent, accurate analysis and the like.

The invention provides a liquid chromatography-mass spectrometry method for detecting 45 veterinary drugs in pond sediment. The liquid chromatography-mass spectrometry method comprises the following steps: 1) extracting a sample; 2) purifying through solid phase extraction; 3) analyzing through liquid chromatography-mass spectrometry: measuring a filtrate in the step 2) by using a liquid chromatograph-tandem mass spectrometer to obtain the peak area of a substance to be measured, substituting the peak area into a corresponding standard curve, and analyzing and calculating to quantitatively obtain the contents of the 45 veterinary drugs in the sediment sample. The high-performance liquid chromatograph-tandem mass spectrometer is used, the liquid chromatography-mass spectrometry method is based on the difference between the polarities of various compounds, the chromatographic column uses a Kinetex C18 chromatographic column having relatively high column efficiency and having the particlesize of 1.7 microns, positive and negative ions are simultaneously scanned, simultaneous analysis of the 45 veterinary drugs can be achieved during an experiment, and high-throughput and high-sensitivity rapid detection requirements can be met.

The invention discloses a measuring method for detecting residual quantities of streptomycin, dihydrostreptomycin, kanamycin, spectinomycin and neomycin in food simultaneously. The method comprises steps as follows: (1) extraction; (2) purification; (3) preparation of a matrix standard working solution; (4) measurement with LC-MS / MS (liquid chromatography-tandem mass spectrometry). The method has the advantages of simplicity in operation, accuracy, high sensitivity and good repeatability, can completely meet technical requirements for corresponding product security detection in China, the European Union, America and Japan and can provide powerful technical support for guaranteeing food security of people in China and sound development of export trades.

The invention relates to a method for measuring the residual quantity of chloramphenicol in propolis by using a high performance liquid chromatography tandem mass spectrum. At present, a measuring method with low detection cost and detection limit reaching 0.1mu g / kg is not found. The method comprises work procedures of standard solution preparation, standard curve preparation, propolis sample solution preparation and chloramphenicol residual quantity detection, wherein the work procedure of propolis sample solution preparation comprises the following steps of: adding 1mol / L NaOH solution to dissolve a propolis sample; diluting with water to dilute a target object in the propolis sample; acidizing with HCLO4 so as to precipitate propolis components in the propolis sample; adjusting the pH value of filtrate of the propolis sample solution to be 10.5 with the 1mol / L NaOH solution; and finally measuring the residual quantity of chloramphenicol in the propolis sample solution through a high performance liquid chromatography and a trebling quadrupole rod tandem mass spectrum. The invention has low detection cost and high detection efficiency, the detection limit energy reaches 0.1mu g / kg, the quantitation limit is 0.3mu g / kg and the linear correlation coefficient is 0.9999.

The invention relates to a method for measuring the residual quantity of paraquat and diquat in food. During pretreatment on a sample, paraquat and diquat in a food sample are extracted by a methanol solution, the extract liquid is purified by C18 and PSA dispersive solid-phase extraction agents, and finally, qualitative and quantitative measurement on the residual paraquat and diquat in the food is achieved through the precise mass number of compound ions with the combination of high performance liquid chromatography-quadrupole rod flight time tandem mass spectrum. The average recycling rate of paraquat is 80.6%-96.8%, the relative standard deviation of paraquat is 3.9%-7.1%, the limit of quantitation of paraquat is 10 microgram / kg, the recycling rate of diquat is 80.8%-97.3%, the relative standard deviation of diquat is 3.5%-7.8%, and the limit of quantitation of diquat is 10 microgram / kg. The method can effectively alleviate matrix interference to residual detection on paraquat and diquat in food, has the advantages of simplicity and convenience in operation, rapidness, accuracy, high sensitivity and good repeatability, and is supplement and improvement on a conventional QuEChERS method.

The method discloses a method for simultaneous detection of vanillin and ethyl vanillin in milk powder, including the following steps: ultrasonic extracting vanillin and ethyl vanillin in milk powder by anhydrous ethanol, precipitating protein, centrifuging the extract liquid to cross membrane, separating by a chromatographic column having a filler of octadecyl silane, detecting by a diode array detector, and quantifying by the external standard method. The method has the characteristics of simple pre-treatment, accurate qualitative determination, and fast quantification, and is suitable for simultaneous detection of vanillin and ethyl vanillin in milk powder.

The invention belongs to the technical field of safe detection of trace drug residues in a water environment, relates to a magnetic nanocomposite material as well as preparation and application thereof, particularly relates to a polypyrrole-modified magnetic multi-walled carbon nanotube as well as preparation and application thereof in detection of sulfonamides, and also provides a sensitive and reliable method for detecting sulfonamide residues in the water environment. The magnetic nanocomposite material provided by the invention is prepared by a method comprising the following steps: step (1) preparing the magnetic multi-walled carbon nanotube in an alkaline solution from a multi-walled carbon nanotube, ammonium ferric sulfate dodecahydrate and ammonium ferrous sulfate hexahydrate; andstep (2) preparing the polypyrrole-modified magnetic multi-walled carbon nanotube from the magnetic multi-walled carbon nanotube, pyrrole and ferric chloride under certain conditions. The prepared polypyrrole-modified magnetic multi-walled carbon nanotube can simultaneously detect eight sulfonamides in the water environment.

The invention discloses a detection method for measuring residual quantity of urea in bean sprout by high performance liquid chromatography, which comprises the following steps of: extracting the urea in the bean sprout by oscillating absolute ethyl alcohol; precipitating protein; centrifuging an extracting solution; deriving on an acid condition by using 9-hydroxyxanthene serving as a derivating agent; separating a derivation product by a chromatographic column which takes octadecyl silane as a filling agent; detecting by using a fluorescence detector; and quantifying by an external standard method. The method has the characteristics of qualitative accuracy, avoidance of false positive, fast quantification and the like, and is suitable for detection on the residual quantity of the urea in the bean sprout.

The invention discloses an analysis method for simultaneously detecting polycyclic aromatic hydrocarbon and hydroxy metabolite level thereof in hair. The method comprises the following steps: cleaningthe hair by using acetone to obtain exogenous extract liquor, digesting the cleaned hair under the condition of 40-80 DEG C to obtain endogenous extract liquor; concentrating the exogenous extract liquor and the endogenous extract liquor, performing purification by using gel permeation chromatographic column, eluting by using eluant, and collecting leacheate; performing separation and purification after concentrating the leacheate; eluting by using a n-hexane solution containing 2-5% of polar solvent, and collecting the component 1, and then eluting by using the n-hexane solution containing 30-60% of polar solvent, and collecting the component 2, performing nitrogen blowing and metered volume on the eluant, and obtaining the content level of a target object in the hair through data processing and quantitative calculation. Multiple exogenous and endogenous polycyclic aromatic hydrocarbons and the hydroxy metabolites thereof in the hair can be detected at the same time, thereby providing an effective method means for the human body exposure health risk evaluation of the polycyclic aromatic hydrocarbons.

The invention discloses a determination method of a perfluorinated compound isomer in soil and / or plants. The method comprises the following steps: (1) extracting a soil and / or plant sample with an ion pair extraction method; (2) concentrating and purifying an extracting solution obtained by the step (1); and (3) detecting a product of the step (2) with an ultra performance liquid chromatography-triple quadrupole tandem mass spectrometer, and comparing the product with an isomer standard product of parallel operation; and quantifying by adopting an internal standard method to obtain the content of each isomer of a perfluorinated compound. The determination method disclosed by the invention is accurate in detection result and has the advantages of high recycling rate, low detection limit, high sensitivity and strong matrix interference resisting capability.

The invention discloses a method for qualitative and quantitative determination of sugar alcohols in foods by an ion chromatograph-mass spectrometer. The method is characterized in that a sample subjected to extraction purification pre-treatment is detected by the ion chromatograph-mass spectrometer; ion chromatography conditions comprise that 90mmoL / L of a sodium hydroxide solution as a separation column eluting solution is used for isocratic elution at a flow rate of 0.50mL / min; a suppressed conductance method comprising a suppressor electric current of 139mA, a feeding amount of 25.0 microliters and a suppressor water source constant flow pump flow rate of 1.0mL / min is adopted; mass spectrometry conditions comprise that an ionization mode APCI- is adopted and a temperature of fainting during acupuncture treatment is 450 DEG C; atomized gas is nitrogen and has purity of 99.9% and pressure of 55psi; and quantitative analysis adopts an external standard quantitative method. The method realizes on-line qualitative and quantitative detection of sugar alcohols in foods, utilizes a self-made SPE column and the ion chromatograph-mass spectrometer to carry out detection, and realizes simple and fast qualitative and quantitative detection of six sugar alcohols in foods.

The invention discloses an indirect background fluorescence colloidal gold immunochromatographic test strip based on double-labeled signal amplification and application thereof. The test strip comprises five parts, namely a PVC plastic back plate paved with fluorescence, a PVC bottom plate, a nitrocellulose membrane, a sample pad and absorbent paper. The invention also discloses a double-labeled colloidal gold probe, the double-labeled colloidal gold probe is composed of a gold nanoparticle labeled biotinylated anti-target object antibody and gold nanoparticle labeled streptavidin, and signalamplification is realized by using superstrong affinity between biotin-streptavidin molecules. According to the fluorescent colloidal gold immunochromatography test strip disclosed by the invention, asample is pretreated by utilizing the immunomagnetic microspheres before detection, and an enriched target object can be efficiently and rapidly separated in an external magnetic field. The test strip has the advantages of good stability, high sensitivity and no matrix interference, can realize rapid qualitative or quantitative detection of the sample, is simple in operation steps, strong in controllability, and has good application prospects.

The invention belongs to the analytical chemistry field and the technical field of pesticide residue detection and particularly discloses a method of splitting and determining a metolachlor enantiomeras a chiral pesticide with an ultra performance bonded phase chromatography-tandem mass spectrometry technology. In the method, a QuEChERS method is adopted to extract metolachlor in tobaccos, grainsand dried fruits, an enantiomer of the metolachlor chiral pesticide is detected by combining bonded phase chromatography chiral stationary phase with triple stage quadrupole tandem mass spectrometry,and a method detected limit is 0.0012mg / kg. The method adopts bonded phase chromatography to rapidly perform chiral separation on the metolachlor for the first time; and by taking supercritical CO2 as a mobile phase, use of a great amount of an organic solvent is saved, and the method is green and environmentally friendly. The method uses bonded phase chromatography for rapid analysis, is beneficial to rapid separation and analysis speed of an isomer, consumes 4mins only and is high in sensitivity.

The invention belongs to the technical field of food detection. The invention relates to a magnetic nano composite material as well as preparation and application thereof in food detection. The invention specifically relates to an application of an ionic liquid dispersion liquid-liquid microextraction and magnetic solid phase extraction (DLLME-MSPE) two-step extraction technology in selective extraction and trace determination of quinolone antibiotics in honey and milk in combination with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS / MS). The invention furtherprovides a sensitive and efficient method for detecting quinolone antibiotics in honey and milk. The saturation magnetization intensity of the magnetic multi-walled carbon nanotube coated with the silicon dioxide modified by the magnetic nano composite material chitosan prepared by the invention is 22.9 emu / g or above. The magnetic nano composite material can be used as a magnetic solid-phase extraction adsorbent for simultaneous quantitative analysis of various quinolone drugs.

The invention provides a method for measuring trace alkaloids and nitrosamines in oral tobacco products. The method includes the following steps that: a) oral tobacco products are sliced, and are added into to an extraction solvent and a deuterated isotope internal standard, extraction is performed with an accelerated solvent extraction method, an extract liquid is collected; b) the extract liquidand a QuECHERS reagent are subjected to vortex mixing for 1-3min, centrifuging is performed at a speed of 9000-11000 rpm for 3-7min, so that a supernate can be obtained; and c) a UPLC-HR-MS method isadopted to perform quantitative analysis on trace alkaloids and specific nitrosamines for the cigarettes in the supernate. With the method disclosed by the invention adopted, 6 trace alkaloids, namely, neonicotine, nornicotine, myosmine, cotinine, nicotelline and N-formyl nornicotine and four specific nitrosamines, namely NNN, NNK, NAT and NAB in the main stream smoke of cigarettes can be measured simultaneously. The method has the advantages of high sensitivity, high accuracy and high selectivity, and is suitable for the rapid determination of trace alkaloids and nitrosamines in batched gum-base oral tobacco products.

The invention discloses an absolute quantification method of rat CYP450 enzyme subtype mass spectrum, and belongs to the field of proteomic technology. Based on an LC / MS / MS technology, the method can be used for realizing absolute quantification of 5 CPY450 enzyme subtypes CYP2D3, CYP270, CYP2A1, CYP2D26 and CYP2B2 in the systems such as rat liver microsomes and the like at the same time by use of a strategy of quantifying enzyme with a specific peptide fragment generated by pancreatin hydrolysis of the CYP450 enzyme. The method disclosed by the invention mainly comprises the following steps of: pretreatment of a protein sample, preparation of a standard curve, preparation of a quality control sample and measurement of the protein sample. The method disclosed by the invention has good linear relationship, high accuracy and good reproducibility, is sensitive, precise and reliable, and can be applied to development of a new drug, study on drug metabolism and evaluation on mutual effect of drugs.

The invention discloses a method for detecting aldicarb and its metabolites in fruits and vegetables by graphene oxide dispersed solid-phase extraction, which belongs to the field of analytical chemistry detection. The method includes the following steps: (1) Extraction: Weigh the sample into a 50ml centrifuge tube, add acetonitrile, homogenize for 1min, then add 4g of anhydrous sodium sulfate and 1g of sodium chloride, shake and centrifuge to collect the supernatant in pears Concentrate to dryness by rotary evaporation in a water bath at 40°C. (2) Purification: Dissolve the residue with acetonitrile-0.1% formic acid aqueous solution, transfer to a 15mL centrifuge tube, add graphene oxide, vortex, stand still, and pass through a 0.22μm organic phase filter membrane. (3) Detection: The sample liquid after the filter membrane is detected by liquid chromatography-tandem mass spectrometry (LC-MS / MS). The beneficial effect of the present invention is that a simple and rapid detection method for aldicarb and its metabolites is established by utilizing graphene oxide dispersive solid-phase extraction technology, the method is simple to operate, low in cost, can reduce sample matrix interference, and is suitable for fruits and vegetables detection.

The invention discloses a method for measuring prothioconazole residue in food. The method includes following steps: S1, extracting; S2, purifying; S3, preparing a matrix standard working solution; S4, using a liquid chromatograph-series ultraviolet detector for measuring, including: (1), qualitative measuring; (2), quantitative measuring. A chromatographic column of liquid chromatograph is a hydrophilic chromatographic column, and a mobile phase measured by liquid chromatograph is a mixture of an acetonitrile solution and a mixed solution according to a volume ratio of 45:55. By the method, matrix interference during prothioconazole residue detection in food can be lowered effectively; the pretreatment method can be combined with HPLC-UV to be applied in qualitative confirmation and quantitative detection of prothioconazole in the food. The method has the advantages of being simple and convenient in operation, quick, accurate and high in sensitivity and repeatability and is a supplement to and an improvement on existing QuEChERS method. Technical requirements on safety detection of corresponding products can be met completely, and powerful technical support is about to be providedfor ensuring food safety and sound development of foreign export trade.

The invention discloses a method for measuring residual quantity of paraquat in food. The sample pretreatment comprises the following steps: extracting paraquat in a food sample by using an aqueous solution of methanol, purifying the extracting solution by selecting C18 and a PSA dispersive solid-phase extraction agent, and finally, combining with high performance liquid chromatography-quadrupole rod flight time mass spectrometer, and carrying out qualitative and quantitative measurement of the residual paraquat in the food through accurate mass number of compound ions. The matrix interference in the process of detecting the paraquat residues in the food can be effectively reduced, the average recovery rate is 80.6-96.8 percent, the relative standard deviation is 3.9-7.1 percent, the quantitative limit is 10 micro-g / kg, the method has the advantages of simple and convenient operation, rapidness, accuracy, high sensitivity and high repeatability and is supplement and improvement of an existing QuEChERS method, the technical requirements on safety detection of corresponding products in China, European Union, America and Japan can be completely met, and a powerful technical support is provided for guaranteeing food safety of Chinese people and sound development of export abroad trade.

The invention relates to a method for determining the residual quantity of chloramphenicol in bee wax by n-hexane pre-treatment-high performance liquid chromatography-tandem mass spectrometry. The method comprises the following steps: pre-dissolving a test sample by adopting n-hexane to form emulsion, and adding water and extracting; carrying out HLB (Hydrophile Lipophile Balance) solid-phase extraction column purification; separating by using an Accucore XL C18 column; and determining by using electric spraying ion source negative ion multi-reaction monitoring mode tandem mass spectrum. Extraction and purification methods, and instrument determination conditions and the like are optimized. A result shows that chloramphenicol has a relatively good linear relation in a range of 0.3ng / mL-10ng / mL, and the correlation coefficient is more than 0.998. The method qualitative limit (S / N>3) is 0.05 microgram / kilogram and the method quantitative limit (S / N>10) is 0.3 microgram / kilogram; the recycling rate of three adding levels of 0.3 microgram / kilogram, 1.0 microgram / kilogram and 2.0 microgram / kilogram is 80.2%-105.2%; and the relative standard deviation (RSD, n=6) is smaller than 8%. The method is rapid, sensitive and accurate.

The invention discloses a method used for simultaneous measurement of vanillin, methyl vanillin, and ethyl vanillin in food. According to the method, measurement of vanillin and ethyl vanillin is carried out after conversion of vanillin and ethyl vanillin into propionates via derivatization. The method comprises following steps: solution preparation, standard stock solution preparation, sample solution preparation, gas chromatography-mass spectrometry qualitative analysis, and quantitative determination. The method can be used for simultaneous measurement of vanillin, methyl vanillin, and ethyl vanillin in cereal grains, liquid milk, single cream, plant oil, and infant formula foods; propionic anhydride derivatization is adopted; detection efficiency is high; detection cost is low; and themethod is rapid and simple, is high in efficiency, and is convenient to popularize.

The invention discloses a method for measuring diarrhetic shellfish poisons in shellfishes by use of immunoaffinity purification-liquid chromatography-tandem mass spectrometry. The method comprises the following steps: extracting a sample by use of an 80% methanol aqueous solution, mixing and diluting with a phosphate buffer solution, and performing immunoaffinity selective special purification, and performing liquid chromatography-tandem mass spectrometry. According to the use characteristics of a diarrhetic immunoaffinity column, parameters of sample liquid, eluate, eluent and the like are optimized; electrospray anions are ionized, a multi-reaction monitoring mode is adopted, and quantification based on an external standard method is achieved. The method is less in matrix interference, strong in purification effect, high in sensitivity and applicable to analysis measurement on diarrhetic shellfish poisons in shellfishes.

The invention discloses a rapid organophosphorus pesticide detection method based on graphene oxide and belongs to the field of analytical chemistry detection. The method includes the following steps of 1, extraction, wherein a to-be-detected sample is weighed and put in a plastic centrifugal tube, acetonitrile is added, homogeneous extraction is conducted for a period of time, anhydrous sodium sulfate and sodium chloride are added, and oscillation and centrifugation are conducted; 2, purification, wherein supernatant is transferred to another clean centrifugal tube, graphene oxide is added for dispersive solid-phase extraction, volution and standing are conducted, and the mixture passes through an organic phase filter membrane; 3, detection, wherein the sample liquid passing through the filter membrane is fed to liquid chromatography-tandem mass spectrometry (LC-MS / MS) for detection. The method has the advantages that the graphene oxide dispersive solid-phase extraction technology is utilized, the simple, convenient and rapid organophosphorus residue detection method is established, and the method is easy to operate and low in cost, can reduce interference of a sample matrix, and is suitable for rapid detection of organophosphorus pesticide in vegetables and fruits.

The invention provides a method for determining 191 pesticide residues through combination of a high-oil complex matrix sample pretreatment technology with UPLC-MSMS, which comprises the following steps of: weighing a proper amount of high-oil complex matrix sample in an outer extraction tube of a centrifugal tube, adding ultrapure water, acetic acid acidified acetonitrile, ceramic homoprotons and extraction salt, adding the extraction salt, a purifying agent and a ceramic homogenizer in an inner insertion tube, nesting the inner insertion tube into the outer extraction tube, screwing, placing the outer extraction tube in full-automatic sample treatment equipment, carrying out repeated oscillation and multiple times of centrifugal treatment, taking a proper amount of supernatant in the inner intubation tube, carrying out nitrogen blowing until the supernatant is nearly dry, adding 1ml of acetonitrile and water (3:2), carrying out ultrasonic redissolution, passing through a 0.22 [mu]m filter membrane, and detecting 191 pesticide residues by using UPLC-MS / MS (Ultra Performance Liquid Chromatography-Mass Spectrometer / Mass Spectrometer). The separation effect of each pesticide component under the chromatographic column is good, the detected detection limit, quantitation limit and other indexes meet the multi-residue analysis of pesticides, and the method can be applied to multi-pesticide residue detection of high-oil complex matrix samples.

The invention discloses a high performance liquid chromatography fluorescence detection method for simultaneously measuring four prohibited and limited additives in tobacco flavors and perfumes. The high performance liquid chromatography fluorescence detection method comprises the following steps: firstly performing oscillating extraction on the tobacco flavors and perfumes by using alcohol, standing to pass through a 0.45 micrometer organic phase filtering membrane to obtain a to-be-detected sample solution; and simultaneously preparing standard solutions of the four prohibited and limited additives, respectively performing detection analysis on the to-be-detected sample solution and the standard solutions by adopting a high performance liquid chromatography fluorescence detector, and then performing quantitative analysis by adopting an external standard method, figuring out contents of the four prohibited and limited additives in the tobacco flavors and perfumes, wherein the four prohibited and limited additives comprise sesamol, beta-naphthol, beta-asarone and safrole. According to the high performance liquid chromatography fluorescence detection method, simultaneous measurement of the four prohibited and limited additives in the tobacco flavors and perfumes is realized. Because special chromatographic columns for phenols are used, the detection time is relatively short; the fluorescence detector is adopted, the selectivity is relatively high, the matrix interference is relatively small, the detection limit is relatively low; no water removal is needed before treatment, and the relative simplicity is achieved in operation.

The invention relates to a method for detecting personal care products in fish bile. The method mainly comprises the following steps: adding internal standards into samples, hydrolyzing the samples, extracting, purifying, analyzing and detecting the samples. The method is characterized by extracting and purifying bile samples by using an optimum protein and phospholipid removal tube and a d-SPE tube based on a multi-isotope internal standard analysis method, measuring the concentration of personal care products (PCPs) in the purified samples by using a UPLC-MS / MS instrument and a GC-MS instrument, avoiding the problems of short sample storage time, high detection limit and serious interference of complex matrix, and establishing a detection method which is simple and rapid and is high in accuracy and sensitivity. In addition, the method is capable of adding or not adding hydrolase into the bile samples before extracting and purifying, comparing and measuring the total concentration andthe free-state concentration of the PCPs in the bile and facilitating the show of the existence forms of the PCPs in the fish bile.

The invention relates to a method for simultaneously detecting vitamins K1, MK4 and MK7. The method comprises the following steps of taking a biological sample, adding an isotope internal standard mixed solution of three substances to be detected, adding an extraction solvent for extraction, centrifuging, taking supernate, drying, dissolving with a reconstitution fluid to obtain a sample to be detected, and detecting by adopting a liquid chromatography-tandem mass spectrometry method, a chromatographic column adopted by the liquid chromatography tandem mass spectrometry being a C18 chromatographic column, the particle size of the C18 chromatographic column being 1.6 to 2.2 mu m, and the length of the C18 chromatographic column being 40 to 60mm. The detection method provided by the invention not only can detect the vitamins K1, MK4 and MK7 at the same time, but also has strong specificity, obtains good chromatographic resolution (retention time difference is greater than 0.5 min) for the vitamins K1, MK4 and MK7, and has advantages of low baseline, less matrix interference, low detection limit, high sensitivity and strong stability.

The invention discloses a chemical labeling and LC-MS combined method, and applications thereof in nucleotide analysis. According to the chemical labeling and LC-MS combined method, N,N-dimethyl-p-phenylenediamine is used for chemical labeling of 10 monophosphate nucleotides containing two methylation modified nucleotides, so that the retention behavior of the modified nucleotides in reversed phase liquid chromatography is improved obviously, and detection sensitivity of the modified nucleotides in mass spectrometric detection is increased. The chemical labeling and LC-MS combined method is high in sensitivity and selectivity; liquid-liquid extraction can be adopted to remove excess labeling reagent DMPA effectively, Strata X solid phase extraction columns can be used for removing excess activator EDC, quantitative determination of extremely-low-abundance methylation modified cytidylate in living bodies can be realized, LC separation sensitivity and ESI-MS detection sensitivity of nucleotides can be improved obviously, and signal responsiveness is increased by 1 to 2 magnitude orders.

The invention provides a staphylococcus aureus colorimetric sensation detection method based on aptamer recognization-HCR (hybridization chain reaction). The detection method comprises the following steps: (1) preparing a DNA (deoxyribonucleic acid) functionalized nano golden probe; (2) preparing aptamer modified magnetic nanoparticles; (3) synthesizing a hairpin probe for a hybridization chain reaction system; (4) preparing an HCR product; and (5) detecting a target. The method has the advantages of constant temperature amplification, high sensitivity, low cost, and the like, and has good application prospects.