92 results about "Inverse gas chromatography" patented technology

A method and apparatus for providing compositional analysis of hydrocarbon fluids from well samples up to a C30+ fraction. The method includes the steps of heating a sample to a temperature of about 220° F., and collecting the liquid and gaseous fractions therefrom. Both the liquid and gaseous fractions are analyzed by gas chromatography. Additionally, the volume of the gas, and the volume, molecular weight and mass of the liquid are determined. The results are then analyzed to provide a total composition of the hydrocarbon fluids.

The invention relates to a method for measuring VOCs in a packaging material by virtue of gas chromatography-mass spectrometry. The method is characterized by comprising the following steps: test sample preparation: rapidly cutting a sample to be measured into pieces for placement in a headspace bottle, and performing sealing for measurement; headspace sample introduction; joint measurement with gas chromatography and mass spectrometry; qualitative confirmation; quantitative analysis; result calculation. According to the method for measuring the volatile organic compound in the packaging material by virtue of gas chromatography-mass spectrometry, the VOCs in the packaging material are measured by adopting headspace sampling gas chromatography-mass spectrometry, a headspace sampling manner is adopted, and no organic solvent is adopted for extraction and concentration, so that interference of an external solvent is reduced; a gas chromatograph-mass spectrometer is adopted for detection, so that the qualification capability of the method is enhanced, and the risk of false positive is reduced; multiple types comprising alcohols, esters, ketones, benzenes and halogenated hydrocarbons can be tested, and the current requirements on testing of the VOCs in the packaging material are basically met.

The invention discloses a method for detecting volatile organic chlorides in resin by using headspace gas chromatography. The method specifically is a headspace gas chromatography (HS-GC) method for detecting residual epichlorohydrin (ECH) and a by-product, 1,3-dichloro-2-propanol (DCP), in a polyamide polyamine epichlorohydrin (PAE) solution. The method is based on a phase balance achieved by a closed headspace bottle before GC detection under the headspace conditions of 60 DEG C and 30 minutes. An experiment proves that a PAE matrix solution affects the phase balance of a to-be-detected substance. Therefore, the accuracy of the method is tested by adopting a standard addition method. The result shows that the method has relatively good precision (RSD is smaller than 2.90%) and accuracy (the recovery rate range is 93.6%-105%). Therefore, the method is suitable for analysis of volatile organic chlorides in a PAE resin solution.

The invention relates to a method for detecting four tobacco-specific nitrosamines (TSNAs) in lateral exhaust gas of cigarettes by virtue of gas chromatography-tandem mass spectrometry. The method is characterized by comprising the steps of capturing the lateral exhaust gas of the cigarettes by virtue of a lateral fishtail cover preprocessed by an ascorbic acid solution and a Cambridge filter preprocessed by an ascorbic acid saturated methanol solution, washing the lateral fishtail cover with a hydrochloric acid solution, adding the washed hydrochloric acid solution and an TSNAs internal standard solution into a container in which the Cambridge filter is collected, extracting the Cambridge filter, processing extraction solution by virtue of a solid phase extraction column to obtain an eluate, drying the eluate with nitrogen, redissolving by virtue of dichloromethane to obtain a sample, and analyzing the sample by virtue of the gas chromatography-tandem mass spectrometry (GC-MS/MS). According to the method, the disadvantages of tedious preprocessing process, low detection sensitivity and strong matrix effect in an existing method are overcome, the preprocessing step of the sample is simplified, and the consumption of organic solvents is reduced; the method has the advantages that the detection is accurate, the sensitivity is high, and the repeatability is good.

The invention provides a detection method for simultaneously measuring residual toluene 2,4-diisocyanate (2,4-TDI), toluene 2,6-diisocyanate (2,6-TDI) and diphenylmethane diisocyanate (MDI) in the product by using precolumn derivatization-gas chromatography-mass spectrography. The method comprises the following specific steps: performing ultrasonic extraction on a sample, performing rotary evaporation and concentration on the extracting solution, reacting in an acidic aqueous solution, neutralizing with an alkali liquor, extracting by using an organic solvent, performing organic phase derivatization, removing excessive derivatization reagents with a buffer solution, taking the organic phase as a to-be-measured solution after solution separation, measuring and confirming by using a gas chromatography-mass spectrometer, carrying out a blank experiment, quantifying by using an external standard method, measuring the target compound in the sample solution, and the like. According to the method, the measurement parameters and test steps of the gas chromatography-mass spectrography are reasonably selected, the content of 2,4-TDI, 2,6-TDI and MDI in leather, artificial leather and textiles can be simultaneously measured by adopting selective ion scanning detection and external standard method quantification, and the results are simultaneously obtained by virtue of one-step pretreatment. The method has the characteristics of high precision, high interference resistance and low detection limit.

The invention discloses an analysis method of fission gas. According to the analysis method, a gas chromatograph is adopted for conducting component content analysis on the sample fission gas, the fission gas of specific volumes is extracted from a sampling container several times, the fission gas extracted every time is fed into the gas chromatograph for gas chromatography, the specific value of target component amounts in the fission gas, of the specific volumes, continuously extracted from the sampling container twice is calculated, the specific value of target component peak areas in two continuous gas chromatography results is calculated, and the numerical relationship between the two specific values is compared. According to the analysis method, a chromatographic separation method for the fission gas is established, the interference of air and especially nitrogen in the air in krypton in the measuring process is avoided through parallel optimization and operation control, and effective separation of krypton, xenon and other interfering components is achieved. The method is easy and convenient to operate, high in efficiency, stable and reliable, and the nitrogen and krypton separation effect is better than that of reported documents.

The invention discloses a gas chromatography-mass spectrometry detection method of 17 phthalate compounds in printing ink. The method comprises the steps of preparing interior label extract liquor, standard working solution and sample solution, calculating gas chromatography-mass spectrometry conditions and determination results, and the like. The improved and optimized detection method has the advantages of being simple and accurate to operate, high in sensitivity, high in recovery rate, good in repeatability and the like. In the method, by utilizing interior label for quantifying, the errors caused by pre-treatment or the precision of instruments can be effectively reduced. The 17 target compounds and the interior label chromatographic peak can achieve better separation degree through the adopted chromatographic conditions and have better linear relativity, the detection limit ranges from 0.2mg/Kg to 2.1mg/Kg, the adding standard recovery rate ranges from 83% to 108%, and the relative standard deviations (RSD) are both smaller than 5%.

The invention relates to a method for determining the content of monomer aromatic hydrocarbons in gasoline through gas chromatography to mainly solve problems of large method establishing difficulty and large valve switching system dead volume of present chromatographic methods. The method, which allows an analyte which is the gasoline to be analyzed through a flow switching center cutting chromatographic device, concretely comprises the following steps: injecting the gasoline sample from a chromatographic shunting introduction port (3), pre-separating through a chromatographic column (4), cutting benzene, an internal standard substance and toluene to a chromatographic column (6) through a flow switching center cutting system (10), further separating, and detecting through a hydrogen flame ionization detector (5); and detecting other aromatic hydrocarbon components through allowing them to enter a damping column (2) after they are separated by the chromatographic column (4), wherein the chromatographic column (4) is TCEP[1,2,3-tri(2-cyanethoxy)]propane capillary chromatographic column; and the chromatographic column (6) is a nonpolar chromatographic column. The method well solves the problems through above technical scheme, and can be applied to the industrial production about the chromatographic analysis of gasoline samples.

The invention provides a gas chromatography/mass spectrometry analysis apparatus of various compositions of white spirit. The apparatus comprises a gas chromatograph main machine provided with a split sample injector, a first capillary pillar, a second capillary pillar, a hydrogen flame ionization detector, a quadrupole mass spectrometer and a controllable temperature programming column box. The split sample injector is connected with the first capillary pillar and the second capillary pillar in parallel, and the first capillary pillar is sequentially connected with the hydrogen flame ionization detector; and the second capillary pillar is connected with the quadrupole mass spectrometer through an interface. The invention also provides a gas chromatography/mass spectrometry analysis method of various compositions of white spirit. The method adopts a same-machine, double-pillar and double-detector method, and a gas chromatographic peak quantitative result and a mass spectrometer qualitative result are simultaneously obtained through one-time sample injection. The peak identification reliability is greatly better than traditional gas chromatographic mixed standard characterization, and unique components of different types of white spirit can be identified in the invention. Fusel, ester, acid and aldehyde addition information can be obtained through adopting an addition method of a same kind of compounds, so different white spirits can be conveniently compared and discriminated.

The invention relates to a molecular engram integral-pin type extraction device suitable for gas chromatography analysis. The device is composed of a high-temperature resistant stainless steel pin and an integral extraction medium in a pin case; the extraction medium is synthesized by one-step reaction according to the molecular engram integral column technology without filling. The device can be connected with a gas collector or an airtight type injector so as to sample, extract and concentrate a specific component in a complex gas sample. The extraction device provided by the invention is designed according to a sample feeding structure of the gas chromatography; the extracted target analyte can be subjected to the thermal desorption with the auxiliary gas as carrier gas under the condition of high temperature in a vaporizing chamber so as to be further separated and detected in the gas chromatography. The device not only has the effects of sampling, extracting and concentrating, but also has the function of storing the sample. When the sample cannot be detected in real time, two ends of the device can be sealed by end caps after sampling, then the sample is stored and the subsequent analysis can be performed as demanded.

About 78.0-91.4% refined lignocellulosic fibres were blended with 8.0-12.0% formaldehyde-based resin, 0.5-2.0% wax and 0.1-8.0% oil in a blowline or a blender before mat forming and panel pressing. Fibres can be from cereal straws or wood species. Wax can be slack or emulsified wax. Oil is selected from different groups including, but not being limited to, vegetable oils, tree oils and any kinds of oils and oil mixtures which consist of fatty acids with 12 to 24 carbon atoms. Inverse Gas Chromatography (IGC) measurement and MDF panel test results have shown that fibre adhesion characteristics have changed significantly, leading to significant panel internal bond (IB) and dimensional stability improvements.

The invention relates to a preparation method of a gas sample in vinyl gas chromatography analysis of 110 methylvinyl silicone rubber. The preparation method comprises the following steps of: adding potassium hydroxide to a sample under certain conditions for pyrolysis to generate an ethylene gas; collecting the gas with a head-space sample bottle; detecting the gas by a hydrogen flame ionization detector through adopting a gas chromatography; and quantifying the gas by an external standard method. The preparation method of the gas sample, disclosed by the invention, is simple in preparation method, short in test time and reduced in analyst body health damage caused by poisonous and harmful reagents and pollution to environment caused by recycling and discharging of waste liquor and meets the requirements of production and detection.

The invention discloses a method for testing the contents of 16 types of polycyclic aromatic hydrocarbons in incense combustion smoke by a thermal desorption/gas chromatography-mass spectrometry. An incense combustion sample combusts in a space being 1.8 m*1.8 m*1.8 m; smoke is collected into a heat desorption pipe containing Tenax-TA filler through a sampling pump; after the heat desorption, GC-MS is used for detection in a selective ion mode (SIM); an external standard method is used for quantification. The result shows that the concentration of 16 types of polycyclic aromatic hydrocarbons shows a good linear relationship in a concentration range of 0.05 to 1.0 mg/L; the relative coefficient r is greater than 0.995; the method detection limit is 0.06 to 1.10 ng/m<3>; the average adding standard recovery rate is 89.2 to 100.7 percent; the relative standard deviation (RSD, n being equal to 6) is 1.7 percent to 5.0 percent. The method has the advantages that the 16 types of polycyclic aromatic hydrocarbons in the incense combustion smoke can be effectively subjected to qualitative and quantitative analysis; the characteristics of simplicity, high speed, high reliability and the likeare realized; the experiment requirements can be met.

The invention discloses a method for testing the surface free energy of graphene by using an inverse gas chromatographic method. The method comprises the following steps: (1) sufficiently drying a graphene sample to be tested in a vacuum drying box; (2) filling a filling column with the sample; (3) mounting the filling column on a chromatographic instrument, introducing helium, and activating the filling column for more than 10 hours; (4) setting parameters of the chromatographic instrument, injecting probe molecules by using a microsyringe under the conditions that the temperature of a column box is 180 DEG C and the carrier gas flow is about 10ml/minute, wherein the non-polar probe molecule is n-5-8 alkyl, and the polar probe molecule is chloroform, tetrahydrofuran, acetone and acetonitrile; (5) starting to acquire data once completing the injection of the non-polar probe molecules and the polar probe molecules respectively in the step (4); and (6) calculating the surface free energy. The method is easy to operate, high in repeatability and reliable in data.

The invention discloses a method for determining lower fatty acid in the atmosphere through dynamic solid-phase microextraction and gas chromatography. According to the method, the solid-phase microextraction and gas chromatography coupling technology is adopted for performing qualitative and quantitative analysis on six kinds of common lower fatty acid in the atmosphere. A sampling pump, a flow velocity controller, a refit three-way container, a solid-phase microextraction device, a sampling bag/bottle and a waste gas bag are involved in the method and are connected through teflon connecting pipes. The dynamic solid-phase microextraction device is adopted for determining the lower fatty acid in ambient air and then moved to a gas chromatography sample inlet after extraction balance is achieved, and the gas chromatography method is adopted for performing thermal desorption detection. The method is accurate, fast to implement, small in interference and high in sensitivity, both precision and accuracy are kept within 10%, the good linear relation that R<2> is larger than 0.99 is achieved, all detection lines are smaller than 10 ppbv, and the recovery rate is 75%-110%. According to the technical scheme, the method is easy, convenient and fast to implement and can meet the requirements of detection work and research.

The invention discloses a solid-phase membrane extraction and gas chromatography-tandem mass spectrometry detection method of organic chlorine compounds in a water body. A C18 solid-phase extraction membrane is used for achieving enrichment of the organic chlorine compounds in the water body. A gas chromatography-tandem mass spectrometry detection method is used for detection. The method is few in operation step, high in sensitivity and good in reproducibility and can be used for measuring the content of the organic chlorine compounds in the water body.

The invention discloses a method for detecting chlorobenzene in sludge through ultrasonic assisted dispersive liquid-liquid microextraction-gas chromatography. The method comprises the steps of (1) preparation of a standard solution, namely preparing 0.1milligram/ml of standard mixed solution comprising m-dichlorobenzene, o-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, and 1,2,3,4-tetrachlorobenzene; (2) ultrasound-assisted extraction, namely putting 1.0g of a sludge sample into a cone centrifuging tube with a turncap, adding acetone, sealing, extracting by ultrasounds, centrifuging extract liquor, then filtering supernate by a microfiltration membrane, and moving into the cone centrifuging tube; (3) dispersive liquid-liquid microextraction; and (4) gas chromatography. The method for detecting the chlorobenzene compounds in the sludge has the high sensitivity. Compared with conventional detection methods such as a soxhlet extraction method, the method saves a large amount of organic solvent being toxic and harmful to human bodies, and little time is used in analysis, so that the method is applicable to the detection on a large quantity of sludge samples.

The invention relates to a method for analyzing the argon mass number abundance value and the specific value in argon by a GC-MS (gas chromatography-mass spectrometry) method. The method comprises the following steps: (1) enabling carrier gas with the purity greater than 99.99% to pass through a purifier so as to enable the purity of the purified carrier gas to be greater than 99.999%; (2) introducing the purified carrier gas into a chromatographic column in which a to-be-detected argon sample is arranged in a gas chromatograph, deoxidizing the to-be-detected argon sample in a nickel contact agent tube after adsorption and desorption effects, and finally measuring in a mass detector so as to obtain an ion flow chromatogram and a mass spectrogram respectively; and (3) acquiring the mass number abundance values of 20Ar, 36Ar, 37Ar, 38Ar, 40Ar, 41Ar and 42Ar in argon respectively by a selected ion method according to the ion flow chromatogram and the mass spectrogram, and determining the specific value according to the relative standard deviation RSD being less than or equal to 5%. The method provided by the invention can be applied to noninvasive detection of human health, human body medical science and animal and plant research.

The invention discloses a GC-MS/MS (gas chromatography-mass spectrometry/mass spectrometry) determination method of residual amount of fluoride ether bacterium amide. The method is mainly used for determining the residual amount of fluoride ether bacterium amide in cereal grains, animal-derived foods and other complex matrix food agricultural products. The method comprises the following steps: homogenizing and extracting residual fluoride ether bacterium amide in a sample with acetonitrile or an acetonitrile solution containing 1% of acetic acid, performing purification and concentration by a C18/PSA solid-phase extraction column, performing GC-MS/MS detection, establishing a standard curve for correction by adopting a blank matrix solution without a pesticide to be detected, and quantifying by an external standard method. According to the method, the average recovery rate is 87.1%-93.8%, the average relative standard deviation (RSD) is 4.1%-5.2%, the detection limit is lower than 0.51mu g/kg, and the method has the advantages of simplicity and convenience in operation, high speed, good impurity removal effect, high sensitivity, good repeatability and accurate qualitative and quantitative properties. According to the method, the technical requirement of 'being standard without exceptions' of the residual limit of 0.01mg/kg can be met, and a powerful technical support is provided for ensuring food safety of people in China and health development of export trades.

The invention discloses a method for determining phenolic compounds in mainstream smoke of cigarettes by supercritical fluid chromatography (SFC), gas chromatography and mass spectrum (GC-MS). The method comprises the following steps that: after the cigarettes are smoked, supercritical fluid is used for extracting glass-fiber filtering discs which capture total particulate matters in the mainstream smoke of the cigarettes, the supercritical fluid chromatography is used for dividing extraction liquid into multiple sections of fractions, and every section of fraction is analyzed by the gas chromatography and the mass spectrum. The method disclosed by the invention has the advantages that the problem of limited peak capacity of GC-MS is solved, the purpose that the compounds among all sections after separation are basically not overlapped can be realized. The result is satisfactory, the quantity of the separated phenolic aroma components is much more than that of direct sampling analysis, a new method is provided for determining the phenolic aroma compounds in the mainstream smoke of the cigarettes, and has significance in evaluating the hazards of smoking on health and promoting research and development of low-hazard cigarettes.

The invention discloses a dispersive solid-phase extraction and gas chromatography-mass spectrometry detection method of organic tin environmental hormones in marine products. The organic tins in themarine products are measured by adopting ultrasonic extraction, freeze degreasing, first time dispersive solid-phase extraction purification, derivatization and back extraction, second time dispersivesolid-phase extraction purification, and gas chromatography-mass spectrometry method. The method is simple in operation, the sample pretreatment can be completed quickly, wherein twice dispersive solid-phase extraction is adopted for purification for the first time, the entire dispersive solid-phase extraction purification process plus the derivatization and back extraction only takes 20-30 min,the result is accurate, the detection limit of nine organic tins is 0.4-1.0 mu g/kg, the recovery rate is 80-117%, the relative standard deviation (n=5) is 3.8-7.5%, the sensitivity is relatively high, the recovery rate and reproducibility are satisfactory, and the dispersive solid-phase extraction and gas chromatography-mass spectrometry detection method can be used for the measurement of the content of the organic tins in the marine products.

The invention discloses a method for detecting substituted aniline substances in sewage or sludge by utilizing gas chromatography-tandem triple quadrupole mass spectrometry, relating to the technicalfield of detection of harmful chemicals. The method comprises the following steps: (1) manufacturing a standard curve; (2) pretreating a sample: carrying out extraction on a sewage sample or a sludgesample to obtain an extraction sample, and enabling the extraction sample to be purified to obtain an analytic sample; and (3) carrying out detection analysis on the analytic sample obtained in the step (2) by utilizing the gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS), and calculating to obtain concentrations of various kinds of substituted aniline substances in the sewage sample or the sludge sample. The method provided by the invention is low in the limit of detection and simple to operate, and can be used for simultaneously and accurately determining the contentof multiple kinds of substituted aniline substances in the sample and solving the problem of impurity interference to chemical substance detection in the sewage or sludge sample.

The invention discloses a gas chromatography-mass spectrometry combined detection method of 17 phthalate compounds in a cigarette stay wire. The method comprises the steps of preparation of internal standard extract, a standard working solution and a sample solution, calculation of a gas chromatography-mass spectrometry condition and a determination result and the like. The improved and optimized detection method has the advantages of being simple and accurate to operate, high in sensitivity, high in yield, good in repeatability and the like. According to the method, an error caused by pretreatment or instrument precision and the like is effectively reduced by adopting internal standard; the 17 target compounds and an internal standard chromatographic peak achieve good separating degree by the adopted chromatographic condition; the gas chromatography-mass spectrometry combined detection method has good linear dependence; the detection limit is 0.2-2.1mg/Kg; the mark recovery rate is 81-113%; and the relative standard deviation (RSD) is smaller than 5%.