842 results about "Mass chromatography" patented technology

The invention provides methods, systems and algorithms for identifying high-resolution mass spectra. In some embodiments, an analyte is ionized and analyzed using high-resolution mass spectrometry (MS) at high mass accuracy (such as ≦75 ppm or ≦30 ppm) and the obtained mass spectra are matched with one or more prospective candidate molecules or chemical formulas. The invention provide, for example, methods and systems wherein the possible fragments that can be generated from the candidate molecules or chemical formulas are determined as well as the masses of each of these fragments. The invention provide, for example, methods and systems wherein the high-resolution mass spectra are then compared with the calculated fragment masses for each of the candidate molecules or chemical formula, and the portion of the high-resolution mass spectra that corresponds or can be explained by the calculated fragment masses is determined.

The invention discloses a method for rapidly detecting polybrominated diphenyl ether residue in a sample, particularly in textiles. The method is characterized by comprising the following steps: (1) the sample is crushed, dipped in base solution and ultrasonically extracted in water bath, and solid phase microextraction is employed to concentrate a target compound; and (2) polybrominated diphenyl ether is qualitatively and quantitatively determined by gas chromatography-mass spectrometry after thermal desorption. The method helps effectively solve the problem of matrix effect that fabric fibers have no solvent extraction, obtains a satisfactory result for the analysis of a selected target compound, has the advantages of low organic solvent consumption, rapid extraction speed, less interference from impurities, high sample recovery rate and the like, and can be applicable to rapidly detecting polybrominated diphenyl ether flame retardant residue in textiles.

The invention provides a thermal desorption-gas chromatography-mass spectrometry fingerprint analysis method of fragrance and flavor for tobacco, comprising the following steps: using the thermal desorption technique during pre-processing the fragrance and flavor for tobacco; using a gas chromatography-mass spectrometry to analyze; establishing a digital fingerprint of sample; judging the similarity of the sample and standard sample by the cosine and euclidean distance method. The thermal desorption technique greatly simplifies the pre-processing operation process and ensures the reliability and stability of the experiment result, and introduces the volatile components into the gas chromatography, in order to conquer the defect of the prior technique that: all the components dissolved in the extraction solvent are introduced into the gas chromatography and the pollution on the instrument is reduced and the service life of the instrument and chromatographic column is prolonged. The analysis method provides a reliable, stable, quick and new method for controlling the quality of the fragrance and flavor for tobacco.

The invention relates to a passive adsorbing and sampling device for detecting the concentration of a volatile contaminant in indoor air, belonging to the field of indoor environment detection. The device comprises a cylindrical adsorbent, a base, an outer cover and a rubber washer, wherein the cylindrical adsorbent is arranged on the base; the outer cover is sheathed outside the cylindrical adsorbent and is sealed with the base through the rubber washer. The device adopts a passive adsorbing and sampling mode, does not need additional power, realizes cylindrical radial adsorption and sampling, has large adsorption area and saves material utilization amount; the target contaminant is various organic volatile contaminants in indoors, and is placed in a thermo desorption tube after sampling; and the device directly uses a gas chromatography (GC) or a gas chromatography-mass spectrometry (GC-MS) with a thermal desorption (TD) or automatic thermal desorption (ATD) function to analyze the concentration of the sample, is small, exquisite and portable, can be placed in indoor to measure the average concentration of the contaminants within a certain time, and can be worn by people to measure the average exposure amount in a certain time, thus greatly reducing detection cost.

The invention belongs to the field of analytical chemistry and relates to the measurement for the transferring amount of phthalate and ethylhexyl adipate in fatty food contact materials, in particular to the use of an adsorbent chromatography colume for purifying and separating the phthalate and ethylhexyl adipate in fatty food simulant liquid, and the use of a combined gas chromatography mass spectrometry for measuring the content thereof. The pre-treatment method which is provided by the invention for the purification and separation of the adsorbent chromatography colume has the advantages of rapidity, strong selection property, small pollution, and low detection limit. The invention can achieve the measurement for the transferring amount of phthalate and ethylhexyl adipate in fatty food contact materials.

The invention discloses a method for detecting the organophosphorus pesticide residue in the tobacco, comprising the following steps of preprocessing by adding water of 5-15 times the weight of the tobacco sample to the tobacco sample to sock the tobacco sample, adding 10-20 ml of extracting agent to each gram of the tobacco sample to extract the tobacco sample, centrifuging to obtain organic-phase supernatant, purifying the organic-phase supernatant, concentrating the organic-phase supernatant by blowing with nitrogen, adding acetone solution to the organic-phase supernatant, and filtering the organic-phase supernatant with a organic-phase filtering membrane of 0.2 Mum to obtain the sample solution, wherein the extracting agent is the mixed solution of acetonitrile and acetone which are at the volume ratio of 1-2:1; and detecting the organophosphorus pesticide residue in the sample solution with gas chromatography and mass spectroscopy by using the chlorazol phosphorus as the internal standard substance after finishing preprocessing. Because the extracting agent is used for extracting in the preprocessing step, the target substance in the tobacco sample can be effectively extracted into the organic phase, and the precision for detecting the organophosphorus pesticide residue in the tobacco can be greatly improved.

A multi-capillary column pre-concentration trap for use in various chromatography techniques (e.g., gas chromatography (GC) or gas chromatography-mass spectrometry (GCMS)) is disclosed. In some examples, the trap can include a plurality of capillary columns connected in series in order of increasing strength (i.e., increasing chemical affinity for one or more sample compounds). A sample can enter the trap, flowing from a sample vial to a relatively weak column to the relatively strongest column of the trap by way of any additional columns included in the trap, for example. In some examples, the trap can be heated and backflushed so that the sample exits the trap through the head of the relatively weak column. Next, the sample can be injected into a chemical analysis device for performing the chromatography technique (e.g., GC or GCMS) or it can be injected into a secondary multi-capillary column trap for further concentration.

The invention provides a system and a method for measuring the content of 57 volatile organic compounds in ambient air. The system comprises a four-way valve, a gas chromatograph and a three-stage cold trap preconcentrator; the four ports of the four-way valve are respectively connected with a pre-separation column, a first secondary separation column, a second secondary separation column and a helium gas source; and the gas chromatograph is provided with a flame ionization detector and a mass spectrometry detector. The method comprises the following steps: (1) preparing a mixed standard use gas; (2) preparing an internal standard use gas; (3) collecting an ambient air sample; (4) establishing a standard curve of a target component; and (5) taking the ambient air sample to be tested, removing interfering substances through the three-stage cold trap preconcentrator, performing gas chromatography-mass spectrometry analysis in the mass spectrometry detector after focusing is performed, obtaining the content of each component according to a peak area and the standard curve established in the step (4), and calculating the concentration of the sample to be tested according to a sample injection volume of the sample to be tested. By adopting the method provided by the invention, the simultaneous analysis of two detectors is achieved by once sample injection, thereby avoiding the influence of the interfering substances on the measurement result simply and effectively.

The invention provides a method for fast detection of residual amount of restricted organic solvents in a textile. An extraction agent is utilized for extraction, and an extraction solution is determined by using gas chromatography-mass spectrometry. Compared with the prior art, a conventional chemical analytical instrument of gas chromatography-mass spectrometry is adopted for detecting the content of a variety of harmful organic solvents in the textile, the pretreatment is fast and simple, detection limits are low, the accuracy is high, and the detection throughput is high, so that the method is very suitable for batch detection of restricted substances; and in addition, by adopting the detection method provided by the invention, the current blank in the method for detecting the content of the variety of the harmful organic solvents in a light and textile product is filled up, important technical support is provided for product quality control and safety monitoring, and the method can be used for detecting the residual amount of the organic solvents in textile products, leather products and various raw materials and further has good economic and social benefits.

The invention relates to a method for separating and preparing key acid flavor components in cigarette mainstream smoke. The method takes the acidic components in the cigarette mainstream smoke as a raw material, the acidic components in the cigarette mainstream smoke are subjected to linear gradient elution through medium-pressure prepared liquid chromatography, and the same volumes of eluted fractions are sequentially collected; and the gas chromatography-mass spectrometry is adopted to analyze all the eluted fractions, and with the help of sense smoke panel test, three key acid flavor components F4, F5 and F6 are screened finally. The result shows that the fraction F4 has obvious functions of improving smoke impact, increasing smoke concentration and reducing stimulation; the fraction F5 has obvious functions of improving aroma quality and smoke impact and increasing smoke concentration as well as the functions of increasing aroma quantity, covering miscellaneous gases and improving permeability; and the fraction F6 has the obvious functions of improving aroma quality, increasing aroma quantity, improving permeability and smoke impact and increasing smoke concentration as well as the function of improving residual taste.

The invention relates to a combined gas chromatography mass spectrometry measuring method for measuring the pesticide residue in leather, which belongs to the field of analytical chemistry. The method adopts normal hexane and acetonitrile to perform ultrasonic extraction to a leather sample and separates and purifies the sample extracting solution by various means such as liquid-liquid extraction, gel permeation chromatograph, adsorbent chromatography column, solidoid extraction column, and the like by aiming to the characteristics that the leather sample has high oil content, the residual processing assistant is complex, and the like, and the pesticide residue of the processed sample extracting solution is measured by the combined gas chromatography mass spectrometry. The invention has the advantages of high selectivity, wide range of application and low detectability, realizes the measurement of the pesticide residue in the leather, creates a new thought for the measurement of the pesticide residue in the leather and fills in a gap for the measurement of the pesticide residue.

The invention belongs to the technical field of food detection, and particularly relates to a method for detecting an antioxidant in food. The method for detecting the antioxidant in the food comprises the following steps of: preprocessing a sample; putting the sample into an organic solvent, extracting the antioxidant, freezing, degreasing, separating extracting solution, repeating the extraction operation for 2 to 3 times, merging the extracting solution, concentrating and fixing a volume; and performing gas chromatography-mass spectrometry detection. The method is high in sensitivity, recovery rate and measured result precision; and compared with the prior art, the method is simple and quick in the preprocessing process, and the detection limit is reduced to 0.1 mg/kg.

The invention belongs to the field of a tea quality identifying method, and relates to a method for identifying the quality of jasmine tea. The method comprises the following steps of: 1, measuring the relative content of aroma ingredients by using a method combining the head space solid phase microextraction in combination with a gas chromatography-mass spectrometry, wherein the sweet smell ingredients comprise alpha-farnesene, cis-3-hexenyl benzoate, methyl anthranilate, indol and linalool; 2, computing the aroma index of the jasmine tea; and 3, determining the quality of the jasmine tea according to the aroma index of the jasmine tea. According to the relevency among various main aroma ingredients and the quality of the jasmine tea, the JTF index (relative content specific value) is determined to be equal to [(alpha-farnesene+cis-3-hexenyl benzoate+methyl anthranilate+indol)/linalool]. According to the method, the quality of the jasmine tea can be effectively and objectively determined, the quality of the jasmine tea with accordant tea base levels can be distinguished, the hard work of specialists can be avoided, and the identifying cost can be saved as well.

The invention relates to a method for quickly detecting trace polychlorinated biphenyls (PCBs) based on a carbon nano tube modification technology, and belongs to the field of analysis and test. Based on the peculiar interaction mechanism among aromatic rings, a carbon nano tube has high capability of trapping the PCBs and low dispersibility in water, and how to quickly separate the carbon nano tube which has micro size and is used as an adsorbent from an analysis object mixture is a problem. The scheme aims to solve the problem. The carbon nano tube involved in the method is subjected to hydrophilic modification and combined with a hydrophilic magnetic nano material to form a composite nano adsorbent in which the modified carbon nano tube is taken as a main body and which has a magnetic response characteristic and high hydrophilicity, the adsorbent in which the PCBs are adsorbed can respond to the action of a magnetic field of a permanent magnet and is quickly separated from a solution, and the residual amount of the trace PCBs in an environment water body is quickly analyzed and detected by combining gas chromatography-mass spectrometry equipment.

The invention relates to a direct current gas insulation electrical equipment partial discharge decomposition simulation experiment apparatus and belongs to the technical field of direct current gas insulation electrical equipment insulation state on-line monitoring. The direct current gas insulation electrical equipment partial discharge decomposition simulation experiment apparatus comprises a direct current power supply system, a gas discharge enclosed air chamber, a detection system and a typical insulation defect physical model, wherein the direct current power supply system comprises a voltage regulation console, a test transformer, a protection resistor, a capacitive voltage divider and a high voltage rectification silicon stack lamp; the detection system comprises a pulse current detection system and a gas chromatography-mass spectrometry detection system; and the typical insulation defect physical model comprises a metal protrusion insulation defect model, a free metal particle insulation defect model, an insulator metal pollution insulation defect model, an insulator air gap insulation defect model and the like. The invention can effectively simulate a typical insulation PD fault and the decomposition process of SF6 under the action of a typical insulation defect PD in direct current gas insulation electrical equipment, thereby providing a solid basis for a system to research direct current PD characteristics, SF6 direct current PD decomposition characteristics and decomposition theories. The invention can be widely used for simulating direct current gas insulation electrical equipment partial discharge.

The invention provides a simple and rapid preparation method and application of a covalent-organic framework compound solid-phase microextraction coating. According to the preparation method, the covalent-organic framework compound coating is quickly formed on quartz fiber, a device needed for the entire synthesizing process is extremely easy, and the method comprises the steps of performing amino-functionalization on the quartz fiber, impregnating surface amino-functionalized quartz fiber in a ground material precursor, repeating performing impregnating for several times, performing simple baking and cleaning the coating, so that the covalent-organic framework compound solid-phase microextraction coating can be obtained. The synthesizing method of the invention is easy to operate, requires few devices, and does not need an organic solvent, and by using the method, the covalent-organic framework compound solid-phase microextraction coating with high-temperature resistance, solvent resistance, acid and alkali resistance, high specific surface area, controllable pore size, and controllable thickness can be quickly prepared. Then the extraction coating is used to enrich environmentalpollutants polychlorinated biphenyls in water and it is detected that the coating has good enriching effects by using gas chromatography-mass spectrometry, thereby showing that the coating has good application prospect in the environment and other fields.

An automated headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry for the determination of four N-nitrosoamines in groundwater samples is developed. Response surface methodology technique was employed to investigate the optimized extraction conditions of headspace solid-phase microextraction using CombiPAL autosampler. The method was applied to determine the N-nitrosamine concentrations in groundwater samples.

The invention relates to a method for rapidly analyzing aroma components of kirschwasser, which belongs to the technical field of analysis and detection. The method comprises the steps of extracting the aroma components of the kirschwasser; detecting and analyzing the acquired aroma components in the kirschwasser by utilizing a gas chromatography and mass spectrometry technology, and qualitatively and quantitatively analyzing the aroma components; sniffing the kirschwasser by utilizing a sensory evaluation method, and sniffing and describing the kirschwasser by selecting six sensory attributes (fruity flavor, flower flavor, fermented flavor, acid flavor, wooden flavor and burnt sweet flavor); and studying the dependence relation between the aroma components in the kischwasser and the six sensory attributes by utilizing a multi-element statistics and analysis method. The aroma components in a kirschwasser sample are analyzed by adopting a headspace solid-phase microextraction gas chromatography-mass spectrometry technology and adopting the multi-element statistics and analysis method, the characteristic aroma components in the kirschwasser can be more intuitively reflected, the aroma components in different kirschwasser can be identified, and the applicability is wide.

The invention relates to a method for enriching and detecting a phthalate ester compound in a wine sample by ionic liquid-dispersive liquid-liquid microextraction. According to the method, the phthalate ester compound in the wine sample is enriched by ionic liquid-dispersive liquid-liquid microextraction, and then trace amounts of a phthalate ester plasticiser in the wine sample are detected by headspace-gas chromatography-mass spectrometry or liquid chromatography. The method is characterized in that extraction, enrichment and purification of trace amounts of a phthalate ester plasticiser in a common wine sample are integrated; the content of the trace amounts of the phthalate ester plasticiser in the wine sample can be measured accurately and effectively; the method can be used in quality control of a wine sample; and the method is rapid and reliable and is simple to operate.

The invention discloses a method for measuring purity values and uncertainty degrees of standard substances of phenol and hydroquinone. The method comprises the following steps: screening raw materials for purity qualification; performing qualitative confirmation on to-be-measured samples by combining a gas chromatography-mass spectrometry with a Fourier transform infrared spectroscopy; measuring the purity of the to-be-measured samples by combining three methods different in principle including a GC method, an HPLC method and a DSC method; sub-packaging the to-be-measured samples; checking uniformity and stability; calculating to obtain the uncertainty degree caused by purity measurement; calculating the uncertainty degree caused by the uniformity and the stability according to step four; and synthesizing all the uncertainty degrees to obtain a total uncertainty degree. The method provided by the invention has accurate qualification, reduces system error, adopts a strict statistical data processing method and a comprehensive uncertainty degree evaluation method, ensures accuracy, stability and traceability of measured values, and obtains high-purity standard substances of phenol and hydroquinone.

The invention relates to a determination method of aroma components in an electronic cigarette aerosol, and belongs to the technical field of assay determination. According to the method, a Cambridge filter is used for collecting grain phase compositions in the electronic cigarette aerosol, absorption bottles collect gas phase compositions in the electronic cigarette aerosol in cold trap conditions, then ultrasonic extraction is carried out by using dichloromethane, and deionized water is combined to carry out liquid-liquid back-extraction, the interference of large amounts of alcohol in the aerosol is eliminated, finally, the gas chromatography mass spectrometry is combined to perform qualitative and quantitative analysis. With the adoption of the determination method of the aroma components in the electronic cigarette aerosol disclosed by the invention, loss or decomposition of volatile aroma components in the electronic cigarette aerosol can be effectively avoided, multiple volatile aroma components can be simultaneously analyzed, the repeatability is better, the sensitivity is high and the operation is simple, and the interference of matrix components and solvents can be avoided, so that the determination method of the aroma components in the electronic cigarette aerosol has certain advantages in detection of the volatile aroma components in the electronic cigarette aerosol.

The invention relates to a method for separating and assaying organic acid and fatty acid substances in saliva, belongs to the technical field of analytical chemistry and particularly relates to the method dedicated to separating and assaying the organic acid and fatty acid substances in the saliva. The method comprises the steps of collecting a saliva sample by adopting absorbent cotton, then, putting the absorbent cotton into a needle cylinder of a syringe, carrying out pushing squeezing by using a push rod of the syringe so as to obtain the saliva sample, carrying out high-speed centrifugation, then, extracting supernatant, then, carrying out salting-out extraction, a methyl esterification reaction and solvent extraction separation sequentially, then, concentrating an extract until the extract is approximately dry, then, carrying out redissolving, carrying out filtrating by a microporous filtrating membrane, assaying the organic acid and fatty acid substances in the saliva by adopting a gas chromatography-mass spectrometry method by using filtrate, making a standard curve, and carrying out quantification by an external standard method. The method provided by the invention can be effectively used for assaying the organic acid and fatty acid substances in the saliva, is feasible, accurate and reliable, is low in detection limit and good in accuracy and has popularization and application values.

The invention discloses a passive sampler for polycyclic aromatic hydrocarbon in indoor air and a sampling testing method thereof and belongs to the fields of sampling and determining of the polycyclic aromatic hydrocarbon. The sampler comprises a sampling bottle and a sampling support, the sampling bottle is filled with granular CarbotrapB or XAD-4 resin which serves as an adsorbent, and the sampling support is a double-layer metal support. Sampling testing steps comprise washing adsorbent; inversely placing the sampling bottle filled with the adsorbent at the position of a circular hole of the upper layer of the sampling support for sampling; extracting the polycyclic aromatic hydrocarbon in the adsorbent; determining quality Mg, i of 15 kinds of PAHs obtained by sampling of the passive sampler through gas-mass chromatography; determining sample rate through fitted line slope fitted by Veq-t; and calculating mean concentration Cg, i of the polycyclic aromatic hydrocarbon in the indoor air. The passive sampler is simple in manufacture and assembly and low in cost, only uses accelerated solvent extraction to extract the polycyclic aromatic hydrocarbon in the adsorbent, greatly reduces use of organic solvent, shortens analysis time and is applicable to sampling of the polycyclic aromatic hydrocarbon in the indoor air.

The invention adopts gas chromatography-mass spectrometry (GC-MS) to originally simultaneously determine residual contents of 9 kinds of organic substances in toy, including ethylene glycol monoethyl ether (EGEE), styrene, trimethylbenzene, isophorone, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, cyclohexanone, bis(2-methoxyethyl) ether, and nitrobenzene. Common detection device is adopted in the method. The method provided by the invention has the advantages of easy popularization, simultaneous detection to save time, improved efficiency, low cost, high detection rate and sensitivity, and high application value in toy production and quality detection.

The invention belongs to the technical field of Wuxi Hao Tea quality detection, and discloses a detection method for rapid grade appraisal of Wuxi Hao Tea. Firstly, aroma of Wuxi Hao Tea is gathered through the headspace solid-phase microextraction (HS-SPME) technique, and the collected aroma is analyzed through gas chromatography-mass spectrometry (GC-MS), so as to construct a Wuxi Hao Tea aroma standard fingerprint spectrum with 35 common peaks; secondly, sensory scores are given to Wuxi Hao Tea samples through sensory evaluations; thirdly, a partial least squares (PLS) regression model for Wuxi Hao Tea aromatic quality is established in a manner that relative contents of the 35 common aromatic components in the Wuxi Hao Tea aroma standard fingerprint spectrum serve as an X matrix and the aromatic sensory scores serve as a Y matrix, the correlation coefficient of the model is 0.973, and the cross-validation correlation coefficient of the model is 0.947. The model has a high fitting degree, can better achieve the aromatic quality predication for Wuxi Hao Tea, and can be used for rapid grade appraisal of Wuxi Hao Tea.

The invention relates to a method for building a cigarette bitter taste index evaluation model based on a taste activity value. The method for building the model comprises the steps of 1) selecting a representative substance of which the alkaloids are the cigarette bitter taste and performing quantitative analysis by gas chromatography-mass spectrometry to obtain a free alkaloid detection result, 2) measuring the bitter taste threshold of each alkaloid in water medium by 3-AFC, calculating the alkaloid taste activity value (TAV) and identifying cigarette key bitter taste substances, 3) building the cigarette bitter taste index evaluation model based on the cigarette key bitter taste substances, and 4) performing fitting effect and model verification analysis on the cigarette bitter taste index and a human body sensory evaluation score by use of Origin 8.5 statistical software. A relatively ideal fitting effect of the built cigarette bitter taste index evaluation model and the human body sensory evaluation is achieved, objective evaluation on the cigarette bitter taste intensity is realized, and technical support can be provided for cigarette bitter taste mechanism revealing, bitter inhibitor development and cigarette bitter taste evaluation.