94results about How to "The determination method is accurate" patented technology

The present invention provides a method for detecting concentration of hydroxyl radical. In the system produced by adding capture agent terephthalic acid sodium salt (NaTA) into hydroxyl radical, 2-hydroxyl terephthalic acid (HTA) is produced by reaction of terephthalic acid sodium salt and hydroxyl radical, which has stable fluorescence and is detected by fluorescence spectrophotometer (excited wavelength lambada ex=315 nm, projecting wavelength lambada em=425 nm), and then the concentration of 2-hydroxyl terephthalic acid is conversed to the concentration of hydroxyl radical. The detecting method of present invention is easy to do, credibility and nicety, especial for used in the conditions of circumstance produced hydroxyl radical at the value of pH<12, or the solution of the hydroxyl radical produced system required the conductivity.

The invention relates to a method for measuring the content of pyrethroid pesticides in mainstream smoke of cigarettes and belongs to the technical field of tobacco chemical analysis. The method comprises the following steps of: extracting a sample by using acetone, purifying the sample by a self-prepared mixed chromatographic column, and detecting on a gas chromatograph; selecting an appropriate adsorbent according to the properties of complex matrixes of five pyrethroid pesticides and smoke, optimizing the using amount of the adsorbent, filling the five adsorbents or water absorbers into a glass chromatographic column from top to bottom, and activating by using 5 milliliters of acetone and 5 milliliters of normal hexane; and transferring sample test solution to be purified into the chromatographic column, eluting repeatedly twice by using 5 milliliters of mixed solvent of the acetone and the normal hexane in a volume ratio of 3:2 at the speed of less than or equal to 5.0 milliliters / minute, collecting eluent, concentrating to 0.5 milliliter on a rotary evaporator, fixing the volume to 2.0 milliliters by using the mixed solvent of the acetone and the normal hexane in a volume ratio of 3:2 to reach 2.0 milliliters, and analyzing on a gas chromatograph-electrochemical display (GC-ECD). The method has the advantages of simplicity, convenience, high efficiency and accuracy.

The invention relates to a determining method and device of nicotine in oral smokeless tobacco products, and belongs to the technical field of novel tobacco detection. The method comprises the following steps of putting a piece of piled filtration paper into a dissolution pool (5), wetting by artificial saliva, weighing 0.5-2.0g of oral smokeless tobacco products, filling into the dissolution pool (5) which is filled up with the piece of filtration paper, placing a collection bottle (6) below the dissolution pool (5), regulating the height of a support (7), and closing a door of a constant-temperature box (4) for dissolution test; and analyzing a release liquid which is collected in real time quantitatively by a high performance liquid chromatograph. An in-vitro dynamic release device consists of a constant-temperature water bath pot (1), a solvent storage bottle (2), a constant-flow pump (3), the constant temperature box (4), the dissolution pool (5), the collection bottle (6) and the support (7). The method provided by the invention has the advantages that operation is simple, convenient and rapid, and selectivity is good; the device has the advantages of simple structure and time and labor conservation, and is convenient to dismount and clean.

The invention relates to a method for measuring hydrogen sulfide in mainstream cigarette smoke, in particular to an ion chromatography method for measuring hydrogen sulfide in mainstream cigarette smoke. The invention provides a method for directly measuring hydrogen sulfide in mainstream cigarette smoke, in order to solve the problem that complete capture and derivatization indirect measurement of hydrogen sulfide in mainstream cigarette smoke are susceptible to interference in prior arts. In the inventive method, an alkaline solution containing ascorbic acid, zinc acetate, ethylenediamine and sodium hydroxide is adopted to capture hydrogen sulfide in the gas phase of cigarette smoke, and anion exchange chromatographic separation and silver working electrode-equipped pulsed amperometric detector are adopted to directly measure hydrogen sulfide (sulfur ions) in the mainstream cigarette smoke. Compared with a conventional method, the inventive method has simpler operation, higher safety and higher interference resistance.

The invention discloses a method for determination of phytic acid content of cotton seed powder. The method comprises collecting different kinds of cottonseed samples planted in different regions, carrying out sample husking, grinding, sieving and moisture balance on the samples, collecting full spectrum data, pretreating the near infrared spectroscopy data through a plurality of pretreatment methods, accurately determining sample phytic acid content through high performance ion chromatography, constructing the optimal PLS model in a full spectrum range through a full cross-validated method, carrying out variable selection on the spectroscopic data, building multiple correction models through a multivariate calibration regression method, building a near infrared spectroscopy correction model and detecting phytic acid content of cotton seed powder through the model. The method utilizes a Buchi NIR Flex-N500 Fourier transform near infrared spectrometer to acquire a spectrogram of cotton seed powder, has a fast determination speed and high accuracy, is environmentally friendly, convenient and efficient and has an important meaning for cultivation of low-phytic acid cotton and promotion of cotton side product processing and utilization.

The invention discloses an online trapping and analyzing method for benzo[a]pyrene in thermal cracking products, and an apparatus thereof, and belongs to the technical field of analytic detection. The method comprises the following steps: filling a sample into a thermal cracking chamber, carrying out aerobic thermal cracking under a programmed heating condition, directly introducing the thermal cracking products to the cold injection port of a gas chromatograph through a transmission pipeline, and trapping through refrigerating by liquid nitrogen; and carrying out programmed heating on the cold injection port after finishing the thermal cracking, allowing the thermal cracking products to be gasified and to enter a gas chromatograph-mass spectrometer, and quantitatively analyzing the benzo[a]pyrene in the thermal cracking products through adopting a selected ion mode. The apparatus comprises helium (1), a nitrogen-oxygen gas mixture (2), a triple valve (3), a flow controller (4), a flow controller (5), a handle (6), a thermal cracker (7), the transmission pipeline (8), a nut (9), an injection isolation pad (10), the cold injection port (11) and the gas chromatograph-mass spectrometer (12). According to the invention, the method has the advantages of good reappearance, high recovery rate, simple operation, and experiment error reduction; and the apparatus has a simple structure.

The invention discloses an immunodetection kit for detecting adulterated cow milk in camel milk and an application thereof, wherein alpha-lactalbumin and alphas1-casein in camel milk are used as characteristic protein of the camel milk, and beta-lactoglobulin and kappa casein in cow milk are used as characteristic protein of the cow milk. After the camel milk characteristic protein is separated and purified, the polyclonal antibody and the monoclonal antibody prepared by the commercialized cow milk characteristic protein and the self-made camel milk characteristic protein can be applied to ELISA detection. The kit mainly adopts an indirect ELISA method to qualitatively or quantitatively detect the content of camel-derived alpha-lactalbumin, alphas1-casein or bovine-derived beta-lactoglobulin and kappa-casein in camel milk, the sample pretreatment process is simple, and after a camel milk sample is repeatedly centrifuged to obtain a milk sample, the content can be directly measured after diluted by diluent, and a large number of samples can be simultaneously detected. The determination method is accurate, rapid and convenient, and has wide practicability and development value in thefield of camel milk adulteration monitoring.

The invention provides a method of measuring residual liquid hydrocarbon content in shale via low-field nuclear magnetic resonance. A shale sample of any shape is used to saturate manganese chloride solution of sufficient concentration; low-field nuclear magnetic resonance is then performed to obtain a nuclear magnetic T2 spectrum in the shale sample; the shale sample is subjected to dewatering prior to dealkylation; a T2 spectrum signal is measured again; amplitude integral difference delta S of the T2 spectral signal is introduced into a calibration relationship (namely, a marking equation)of hydrocarbon content and the signal, built in the method, so as to calculate hydrocarbon volume in shale of unit volume; the result is that the hydrocarbon volume in shale of unit volume is presented by percentage, which is considered as residual liquid hydrocarbon content in shale. The problems are effectively avoided that samples experience light hydrocarbon loss due to crushing pretreatment and that insufficiency of solvent polarity leads to incomplete extraction of heavy hydrocarbons; the method is suitable for precisely measuring residual hydrocarbon content in shale and is an effectiveand quick measuring method.

The invention discloses a method for measuring the length of a liquid core of a casting blank, which belongs to the technical field of steel continuous casting. The method comprises the following steps: during the continuous casting, a tracer is added in the liquid core in the center of the continuous casting blank and flows to the tail end of the liquid core, when the continuous casting blank is cooled down and solidified, the tracer is sampled and is subjected to split detection. The method for measuring the length of the liquid core of the casting blank, which replaces the prior bolt striking method, can accurately and directly find the liquid core position of the casting blank; and by utilizing the method, the actual solidifying condition of the casting machine can be better shown, and the cross sectional shape of the liquid core and the cross sectional diameter of the liquid core with the corresponding casting blank length can be measured. The measurement method of the invention has the advantages of simpleness, accuracy, easy operation, low cost, fast result derivation and convenient popularization and application.

The invention discloses a method for detecting carbamate pesticide content in total particle matter in cigarette mainstream smoke, belonging to the technical field of tobacco chemical analysis. The method comprises the steps of putting a Cambridge filter with trapped total particle matter in cigarette mainstream smoke into a conical flask with a plug; adding 100ml of mixed solvent of ethyl acetate and cyclohexane according to the volume ratio of 85:15; putting the conical flask on an ultrasonic generator to extract for 30min; concentrating the extracted liquid to 0.5ml after drying; using the mixed solution of toluene and acetonitrile (1:3) to reach a volume of 2ml to be purified; putting Envi-carb / NH2SPE small column on a solid phase extracting device, adding 2g of anhydrous sodium sulfate to the Envi-carb / NH2 composite column; using 5ml of mixed solution of toluene and acetonitrile according to the volume ratio of 3:1 to perform activation; transferring the to-be-purified sample test liquid to the composite column, using 5ml of mixed solvent of acetonitrile and toluene according to the volume ratio of 3:1 to perform elution for three times, wherein the rate is not more than 5.0ml / min; concentrating the eluate to 0.5ml, using 5ml of dichloromethane to exchange solvents for two times, concentrating the exchanged test liquid to 1ml, and then performing analysis. The invention has the advantages of simple and convenient method and accurate detected data of pesticide content.

The invention relates to a method for measuring 31 components in compound radix salviae miltiorrhizae extract or related medicinal materials simultaneously. The method adopts a direct series-reverse phase-hydrophilic interaction chromatography mass spectrometer combination method and comprises steps as follows: step one, preparing a sample solution; step two, preparing series of standard solutions; step three, preparing an internal standard solution; step four, preparing a solution for test products; step five, injecting the solution obtained in the step four into a direct series-reverse phase-hydrophilic interaction liquid chromatography mass spectrometer combination system so as to obtain an extracted ion flow diagram of 31 analytes, and calculating content of the 31 components in the compound radix salviae miltiorrhizae extract or the related medicinal materials according to the extracted ion flow diagram.

The invention discloses a method for determining the contents of chlorogenic acid, luteolin and apigenin in longleaf campanumoea root. The method comprises the following steps: carrying out gradient elution, wherein chromatographic conditions are as follows: a chromatographic column is Pntulips Bp-C18(4.6mm*250mm and 2.5 microns), a flow phase A is acetonitrile, a flow phase B is methanol, a flowphase C is a 0.1% phosphoric acid water solution, the detection wavelength is 330nm-350nm, the column temperature is 20-30 DEG C, the flow speed is 0.8mL.min(-1)-1.2mL.min(-1), and the feeding quantity is 5-15 microliters; preparing a reference substance solution; preparing a testing sample solution; and carrying out determination by virtue of an HPLC method. By utilizing the HPLC method and optimizing an extraction method and the chromatographic conditions, a quantitative assay of multi-components by single-marker is established and is used for determining the contents of active components inthe longleaf campanumoea root, and a research basis is provided for the formulation of medicinal material quality standards, the reasonable development and utilization of resources and the like. Themethod is accurate, high in sensitivity and good in repeatability, the result is reliable, and basis is provided for the quality control and evaluation of the longleaf campanumoea root.

The invention discloses a super absorbent polymer and a measuring method of the super absorbent polymer in a hygienic product. The technical scheme is as follows: utilizing inorganic salt ion Mg2+ and the quantitative chelation of the super absorbent polymer for soaking a certain quantity of super absorbent polymer in certain concentration and volume of excessive Mg2+ ion signed solution, and stirring so as to conduct complexation reaction on the super absorbent polymer and salt ions in the mixture, and utilizing EDTA (Ethylene Diamine Tetraacetic Acid) back titration method for measuring the chelation coefficient K of the super absorbent polymer; and soaking the hyginenic product to be measured in the certain concentration and volume of the excessive Mg2+ ion solution, and stirring so as to conduct the complexiation reaction on the super absorbent polymer and the Mg2+ ion, and utilizing the EDTA back titration method for indirectly measuring the quantity m of the Mg2+ ion in complexation with the super absorbent polymer, wherein m / k is the content of the super absorbent polymer in the hyginenic product. The method has the advantages of simple operation, objective and real measured data, good repeatability, low cost and easy operation.

The invention discloses a method for measuring bacitracin and the content of the preparation thereof by the turbidity method, and the method contains the following steps: the preparation of standard solution, the preparation of test solution, the preparation of test organism suspension, the content measurement, etc. The antibiotics-microbial test and multi-dose turbidity method of the invention are adopted for measuring the bacitracin and the content of the preparation thereof, thus the test method is accurate and effective and has low cost, and test results can truly reflect antibacterial activity of the bacitracin and the preparation thereof; the method has stronger practicality and operability in the production and the quality control of the drug and the preparation thereof.

The invention relates to a method for detecting musk xylene in a tobacco additive and belongs to the technical field of detection of tobacco additives. The method comprises the following steps of: weighing 1.0g of tobacco additive and putting into a 50mL conical flask with a plug, adding 10mL of ultrapure water of which electrical resistivity is 18.2 M Omega and dispersing a sample, adding 0.3mL of D15-musk xylene interior label solution with the concentration of 1mu g / mL, and 10mL of cyclohexane, oscillating and extracting at the temperature of 25 DEG C for 10 minutes, centrifuging a mixed solution at rotation speed of 4,000r / min by a centrifugal machine for 10 minutes, extracting an upper-layer organic phase, adding 10mL of chromatographically pure cyclohexane into a water phase of which the upper-layer organic phase is extracted, performing secondary extraction under the same operation conditions, centrifuging, and extracting an upper-layer organic phase; and mixing the organic phases extracted twice, drying by using anhydrous sodium sulfate, and metering the volume to ensure that the volume is 1mL for gas chromatography-mass spectrometer (GC-MC) determination. The method has the advantages of high sensitivity and capacity of effectively determining the content of musk xylene in the tobacco additive, and can determine the content of the musk xylene accurately and quickly, and is suitable for monitoring and self-inspection work of the highly-concerned musk xylene in the tobacco additive.

The invention discloses a method for simultaneously measuring the content of multiple active ingredients in eucommia ulmoides. The method adopts high performance liquid chromatography for analysis; the chromatographic condition is taking octadecylsilane bonded silica as a filler; the mobile-phase gradient elution process is: the mobile phase A is methanol, and the mobile phase B is an aqueous solution of phosphoric acid with mass concentration of 0.1%; the content of the mobile phase B is increased from 30% to 70% by mass according to the first-order linear gradient in 0.01-30.00min, reduced to 30% in 30.00-30.01min and kept at 30% in 30.01-40.00min; the flow rate is 0.8ml / min; the column temperature is 30 DEG C; the sample injection volume is 5mul; the detection wavelength detection process is: the 254nm wavelength is selected in 0.01-7.00min, the 277nm wavelength is selected in 7.00-12.50min, and the 254nm wavelength is selected in 12.50-40.00min; and multiple active ingredients include geniposidic acid, chlorogenic acid, pinoresinol diglucoside and rutin. According to the invention, the method is verified by linear relation survey, stability test, precision test, reproducibility test and sample injection recycling test, and the analysis method is proved to be accurate and reliable.

The invention discloses a method for measuring nitrofuran antibiotics in cosmetics. The method comprises the following steps: (1) pretreating a sample, namely adding the sample into a mixed solution of acetonitrile and methanol in a volume ratio of 70:30, uniformly mixing, performing ultrasonic extraction, centrifuging, airing supernatant till the supernatant is nearly dry, dissolving residues in a mixed solution of a 15mmol / L ammonium acetate solution and acetonitrile according to a volume ratio of 85:15, and sieving the solution through a micro-porous filter membrane with the size of 0.22 micron, thereby obtaining filtrate for later use; (2) performing high performance liquid chromatography separation on the filtrate, eluting a mobile phase by a gradient elution program, and quantifying according to an external standard method; and (3) confirming a detected positive sample by high performance liquid chromatography-mass spectrometry / mass spectrometry. According to the method, four nitrofuran antibiotics such as macrodantin, furazolidone, furaltadone and nitrofurazone are simultaneously detected. The method is accurate, reliable and high in sensitivity.

The invention provides a determination method of adsorption performance of processing agents of a drilling fluid, especially a determination method of high temperature adsorption performance of the processing agents of the drilling fluid. The method comprises: drilling fluid containing treating agents is subjected to hot filtration, for example, leakoff and back pressureat a high temperatureto obtain a liquid in the system; the percent of the characteristic elements in the treating agents in the liquid phase is determined to calculate the mass of the drilling fluid treating agents which is not adsorbed at the high temperature; and further the adsorption amount of the treating agents in the clay at the high temperature can be calculatedto achieve evaluation of the adsorption performance of the processing agent of the drilling fluid at the high temperature. The determination method is accurate and scientific, is especially suitable for high temperature adsorption performance evaluation of the treating agents of the drilling fluid, and can provide technical support for accurately designing and optimizing the molecular structure of the treating agents of the drilling fluid and preparing rational formula of the drilling fluid.

The invention discloses a determination method for para-hydroxybenzoate alkyl esters in mouth cigarette. The determination method is characterized by comprising the following steps: extracting a sample by adopting a solution extraction method; purifying the sample by selecting QuECHERS (Quick, Easy, Cheap, Effective, Rugged and Safe) reagent; determining the sample through an ultraperformance convergence chromatography-tandem mass spectrometry technology. The determination method disclosed by the invention has the advantages that pretreatment steps are relatively simple, and used organic solvents are fewer; the dosage of the organic solvents used in a determination process is also small, determination of various components can be realized within three minutes, and the determination efficiency is high; compared with liquid chromatography, according to the determination method, the detection limit is low, the determination method is more suitable for determination of trace components, and the determination method for the para-hydroxybenzoate alkyl esters in the mouth cigarette is relative green, efficient and accurate.

The invention relates to a construction method of a HPLC specific chromatogram of a daphne genkwa standard decoction and a component content determination method of the daphne genkwa standard decoction, and the component content determination method of the daphne genkwa standard decoction comprises the following steps: (1) respectively sucking a reference substance solution and a to-be-determineddaphne genkwa standard decoction sample solution, injecting the solutions into a high performance liquid chromatograph, and determining corresponding peak areas; (2) calculating the content of genkwanin through an external standard method; and (3) calculating the contents of apigenin-7-O-beta-glucuronide, apigenin and hydroxygenkwanin through a quantitative analysis of multiple components by single marker. According to the method, the content of genkwanin is calculated through an external standard method, and then the content of apigenin-7-O-beta-glucuronide, apigenin and hydroxygenkwanin is calculated through a quantitative analysis method, so that the operation steps of content determination of four components can be effectively simplified, the determination time is shortened, the working efficiency is improved, and quantitative analysis of chemical components of the genkwanin standard decoction is realized.

The invention provides a high performance liquid chromatography detection method for cyanoacetamide. The chromatographic conditions adopted by the method include that: the chromatographic column is Polar-Silica, the particle size is 5 micrometers, the length is 250mm, the diameter is 4.6mm, and the aperture is 120 angstrom; the mobile phase is a mixed system of acetonitrile and methyl chloride; and the detector is ELSD. The detection method provided by the invention has the advantages of rapidity, accuracy, high selectivity, simple sample treatment, and is suitable for qualitative and quantitative detection of cyanoacetamide industrial crude products and intermediates.

The invention relates to a liquid chromatography-tandem mass spectrometry determination method of fluensulfone metabolite, and belongs to the technical field of pesticide residue detection. The method comprises the following steps: extracting a sample with an organic solvent by adopting a QuEChERS pretreatment method, centrifuging, carrying out dispersive solid-phase extraction and purification on supernate, and determining by using liquid chromatography-tandem mass spectrometry. The liquid chromatography-tandem mass spectrometry analysis method of the fluensulfone metabolite is established for the first time, and is suitable for extraction and determination of fluensulfone metabolite residues in samples such as vegetables, melons and fruits, tobaccos and the like. When the residual quantity of the fluensulfone metabolite is measured, a blank sample of the fluensulfone metabolite is adopted for matrix standard matching, so that the measurement result is more accurate.

The invention discloses a method for detecting the activity of beta-1,4-xylosyltransferase in xylan synthesis by utilizing high performance liquid chromatography (HPLC). The method comprises the following steps: extracting plant microcapsules, carrying out an addition reaction between Xyln-AA and UDP-Xyl by utilizing beta-1,4-xylosyltransferase existing in the microcapsules, detecting the addition product by utilizing the HPLC, and detecting the activity of XylT in plants. Because XylT is a key enzyme in xylan synthesis, and the xylan is a main ingredient of biomass hemicellulose, the biomass hemicellulose is well utilized by understanding a xylan synthesis mechanism. The invention provides a reliable way for deeply researching the xylan synthesis mechanism and regulating xylan ingredient in hemicellulose, genes formed by xylan can be researched and regulated by screening xylan synthesis defect plants according to the needs, or the requirements on different contents of the hemicellulose in materials are met by regulating key genes influencing XylT synthesis.

The invention belongs to the field of chemistry and is suitable for measuring four elements including nitrogen, hydrogen, carbon and sulfur in tree moss concrete. The invention relates to a method for measuring nitrogen, hydrogen, carbon and sulfur in tree moss concrete, which comprises the following steps of: 1, quantitatively weighing tree moss concrete samples, and adding the same into a special sample cup; 2, quantitatively introducing a carrier gas (helium 0.14MPa), a power gas (argon 0.4PMPa) and a burning gas (oxygen 0.1MPa) in per 1 gram of tree moss concrete; 3, cracking the tree moss concrete at high temperature, burning in pure oxygen, and converting nitrogen, hydrogen, carbon and sulfur in the samples into gases including N2, H2O, CO2 and SO2; and 4, separating N2, H2O, CO2 and SO2 through chromatographic columns, and carrying out thermal conductivity detection on the percentages of nitrogen, hydrogen, carbon and sulfur.

The invention discloses an arsenic-free detection method of iodide ions in a trace serum sample for individual iodine nutrition evaluation. The arsenic-free detection method overcomes the defect thata highly toxic reagent is used in an existing method, adopts a sodium chlorate-sulfuric acid solution for digesting the serum sample at the temperature of 110 DEG C, uses iodine catalyzing the reduction reaction of sodium nitrite and ferric thiocyanate, and measures a concentration change speed of Fe(SCN)6<3-> to be in direct proportion to the iodine content; the reaction temperature and the reaction time are precisely controlled, the absorbance of the remaining Fe(SCN)6<3-> is measured, and the iodine content and the logarithm of the absorbance are in a linear relation. The establishment of the arsenic-free detection method can further meet the gradually increased demand of people for knowing the iodine nutrition level, a powerful method and means are added to serum iodine detection of iodine deficiency disease prevention and treatment monitoring and iodine nutrition evaluation, and the arsenic-free detection method has important public health practical significance and practical application value.

Present invention relates to a method determining ancient petrograph, belonging to study of ancient relic field. It features inputting given definite date two different epochal petrographs into computer, detecting out lightness value of two petrographs by computer lightness value detection system, and using said lightness value as scale to estimating scaling relation of petrograph date with lightness value, then capable of determining out any petrograph date. Said invention provides scientific, accuracy and normative verification method.

The invention discloses a method for measuring trace polybrominated diphenyl ether in high concentration chemical oxygen demand (COD) landfill leachate, belonging to the detection field. The method comprises the steps of: continuously carrying out liquid-liquid extraction, carrying out rotary evaporation concentration, treating the liquid by concentrated sulfuric acid until the liquid is colorless, washing the liquid by water until the liquid is neutral, purifying by a multilayer silica gel column, concentrating by blowing nitrogen, carrying out gas chromatography (GC), carrying out negative chemical ionization mass spectrometry (NCIMS) analysis, and the like; due to the organic coordination of all the steps, the trace polybrominated diphenyl ether in high-concentration COD landfill leachate can be measured; and the target substance can be accurately analyzed by utilizing the conditions of extraction, purification and instruments, so that good recovery rate and purification effect can be obtained.

The invention relates to an extraction method and determination method for residual maleic hydrazide in tobacco, and belongs to the technical field of detection of pesticide residues in tobacco. The extraction method of residual maleic hydrazide in the tobacco includes the following steps: carrying out magnetic stirring and extraction of a tobacco sample and hydrochloric acid for 1-3 h under a condition of the temperature of 100-150 DEG C, then cooling to room temperature and centrifuging, then allowing the supernatant to pass through a column, purifying, and then eluting with water. The extraction method for residual maleic hydrazide in the tobacco has no need for reflux, has the advantages of simple and convenient operation, simple and fast process and high extraction efficiency, is suitable for extraction of residual maleic hydrazide in the tobacco samples, and has good consistency with a determination result of a national standard method.

The invention discloses a method for determination of padimate in cosmetics, wherein the method includes the following steps: (1) pretreating samples; (2) analyzing padimate by high performance liquid chromatography, and optimizing high performance liquid chromatography conditions; and (3) drawing a standard working curve, quantifying by adopting an external standard method, and calculating the content of padimate. The method for determination of padimate in the cosmetics adopts the high performance liquid chromatography for simultaneous determination of padimate A and padimate O in the cosmetics; the samples detected to be positive by the high performance liquid chromatography are further identified by using high performance liquid chromatography-mass spectrometry / mass spectrometry. The method is accurate and fast, is high in sensitivity, and has a great significance for monitoring of the cosmetics quality safety risks.

The invention discloses an arsenic-free detection kit for iodide ions in a trace serum sample. According to the arsenic-free detection kit, the defect that a highly toxic reagent is used in the priorart is overcome, a sodium chlorate-sulfuric acid solution is used for digesting a serum sample at 110 DEG C, iodine is used for catalyzing the reduction reaction of sodium nitrite and ferric thiocyanate, and the concentration change speed of Fe(SCN)6<3-> is measured to be in direct proportion to the iodine content; the reaction temperature and the reaction time are precisely controlled, the absorbance of the remaining Fe(SCN)6<3-> is measured, and the iodine content and the logarithm of the absorbance are in a linear relation. An existing serum iodine quantitative determination method has thedefects of complex reagent preparation, easiness in pollution and decomposition, large dosage of dangerous reagents and large required serum amount. The arsenic-free serum iodine detection kit researched by the invention is convenient to operate, easy to carry, high in safety and suitable for clinically developing individual iodine nutrition detection.