714 results about "Gas chromatography–mass spectrometry" 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 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.

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 discloses a method for analyzing amine substances in dansyl chloride derived-plasma based on liquid chromatography mass spectrometry. The method is characterized in that dansyl chloride is used as a derivatization reagent to perform derivatization on a metabolite containing primary amine and secondary amine, therefore the retention capability of the amine substances in reversion phase chromatography is increased, the ionization efficiency in mass spectrometric detection is increased, and the purpose of increasing the quantitative accuracy and detection sensitivity of the amine substances is achieved. The method has wide coverage for amine metabolites (comprising amino acid, methylation products, acetylation products, dipeptide and the like), can utilize 100 [mu]L of plasma samples to detect 113 amine substances, supplies the outline information of metabolome of the amine substances, and has the characteristics of good specificity, high accuracy and repeatability, less reagent consumption and the like.

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 discloses a method for detecting catecholamine in blood plasma by liquid chromatography tandem mass spectrometry. The method comprises the following steps of preparing a standard product, separating by liquid chromatography, detecting by a mass spectrum, drawing a standard curve, and detecting the catecholamine in the blood plasma. The method has the beneficial effects that the catecholamine is detected by innovatively applying a high-flux liquid chromatography tandem triple quadrupole mass spectrograph; protein is precipitated by acetonitrile, dansyl chloride is used for performing derivative reaction, and the liquid chromatography tandem triple quadrupole mass spectrograph is used for detecting after extraction, so that the pretreatment steps are simple, the interference of a matrix in the blood plasma is effectively removed, and the specificity is good; after the derivatization of dansyl chloride, the detection sensitivity is effectively improved; the high-flux liquid chromatography tandem rod mass spectrograph is used for detecting, three types of catecholamine, including dopamine, epinephrine and norepinephrine, in the blood plasma can be quantitatively and accurately detected; the detection time is short, the flux is high, the detection sensitivity is high, the specificity is good, and the cost is low.

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 discloses a simple method for identifying different ageing years of dried tangerine or orange peel and citrus chachiensis hortorum medicinal materials by virtue of infrared spectroscopy.The method comprises the following steps: 1) selecting dried tangerine or orange peel and citrus chachiensis hortorum medicinal materials, smashing, and sieving; 2) acquiring infrared spectroscopy (4000-400cm<-1>) of a sample and gas chromatography-mass spectrometry data of corresponding volatile oil; 3) discriminating and analyzing years of the dried tangerine or orange peel and citrus chachiensis hortorum according to characteristic peaks of the infrared spectroscopy; 4) analyzing variation of an infrared characteristic peak by combining a gas chromatography-mass spectrometry qualitative result; and 5) with 1635cm<-1> absorption peak as a base peak, judging the year of the dried tangerine or orange peel according to a strength ratio of 1742cm<-1> absorption peak to 1635cm<-1> absorptionpeak. The invention establishes an accurate, rapid, lossless and pollution-free traditional Chinese medicinal material analysis method, the traditional Chinese medicinal material dried tangerine or orange peel on the market can be rapidly analyzed, the years of the dried tangerine or orange peel and citrus chachiensis hortorum can be judged, and an identification reference base is provided for related adulterate and shoddy dried tangerine or orange peel products.

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 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 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 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.

The invention provides an HS-GC-MS (head space-gas chromatography-mass spectrometry) method for measuring 32 volatile substances in a food contact plastic product simultaneously. The food contact plastic product is sheared into granules, and the granules are subjected to static HS treatment at the temperature of 90 DEG C for 40 minutes, measured with GC-MS and quantified with an external standard method. According to the method, the limits of quantitation of different volatile substances are all under 5 mg/kg, the linearity range is from 0.5 mu g to 10 mu g, the linearly dependent coefficients are all larger than 0.9975, the average recovery rate ranges from 75.2% to 108%, and the RSD (relative standard deviation) ranges from 0.4%-9.7% (n is equal to 6). The method is simple and convenient to operate, high in sensitivity and good in accuracy and can be better applied to detection of the volatile substances in the food contact plastic product.

The invention relates to a method for separating alkaline scent ingredients from the main stream smoke of cigarettes, in particular to a method for separating trace alkaline scent ingredients from alkaline ingredients containing a large amount of alkaloids such as nicotine and the like. The method comprises the following steps of: extracting collected smoke particulate matters, namely unblended cigarettes with high-quality tobacco leaves serving as raw materials, performing acid washing, concentrating, distilling under vacuum and the like to obtain a cut fraction F2 with low alkaloid content;separating the cut fraction by a gas chromatography separation method to obtain 5 cut fractions SF1 to SF5; and performing the combination of gas chromatography-mass spectrometry and sensory evaluation on SF1 to SF5, and selecting a cut fraction SF4 with an obvious sensory effect. By the method, a large number of alkaloid ingredients which do not contribute to the scent ingredients of the cigarettes are removed, and low-content active alkaline scent ingredients are enriched; and the method is applied to the field of the perfuming of cut tobaccos of the cigarettes, and has an important significance for improving the smoking quality of the cigarettes in China.

The invention discloses a gas chromatography-mass spectrography combined detection method for eight monohydric polyaromatic hydrocarbon in urine. The method comprises the following steps of: (1) respectively transforming the monohydric polyaromatic hydrocarbon and the deuterated monohydric polyaromatic hydrocarbon in a mixed standard solution into corresponding trimethylsiloxy polyaromatic hydrocarbon, carrying out GC-MS (gas chromatography-mass spectrometry) analysis on eight derivative mixed standard solutions; (2) shaking up a urine sample unfrozen under room temperature, and carrying out pretreatment and derivatization on the urine sample, sequentially detecting the content of eight monohydric polyaromatic hydrocarbon in urine sample. The method is suitable for detection and research on biomarkers exposed by polyaromatic hydrocarbon in urine of various common samples, can simultaneously detect eight monohydric polyaromatic hydrocarbon in urine, and has the advantages of being low in detection limit, excellent in stability, simple in pretreatment, rapid and accurate.

The invention provides a method for identifying the honey of Apis cerana and the honey of Apis mellifera. The method achieves the purpose of identifying the two kinds of honey based on the differenceof alkane components in the two kinds of honey. Honey samples are extracted with petroleum ether and then detected via gas chromatography-mass spectrometry; and detection results show that the alkanecomponents of the honey of Apis cerana and the honey of Apis mellifera are different, the honey of Apis cerana contains C37 alkanes, and the honey of Apis mellifera contains C31 alkanes. It is confirmed that the component difference is only related to bee species after detection and analysis of a large number of samples, and the influence of plant sources on identification is excluded. The differential alkane components are stable in honey and are not affected by concentration processing and shelf life. The method of the invention is reasonable in design, convenient, quick and accurate in identification, and is applicable to both the identification of the sources of raw honey and commercial bee species and the identification of the honey of Apis cerana blended with a certain proportion ofthe honey of Apis mellifera.