136 results about "Capillary gas chromatography" patented technology

The nature of this invention encompasses the creation of a capillary gas chromatography (GC) column assembly and a thermal modulator used to heat or cool the column assembly in a very thermally and chromatographically efficient manner. The GC column assembly described herein consists of capillary GC column material, such as fused silica or metal capillary tubing, which is constrained to lie in a flat, ordered, spiral pattern and then encased between two thin opposing surfaces. The resulting column assembly is flat, dimensionally stable and can be very efficiently thermally modulated. The resulting column assembly also takes up very little space, has very little thermal mass, and can be easily and accurately manufactured. The column assembly can be adapted for chromatographic use by affixing it to the surface of a thermal modulator described herein by means of adhesive force or by mechanical compression, and then by attaching the free ends of the exposed column material to the input and output ports of the chromatographic device. The temperature of the thermal modulator and capillary column assembly is to be controlled by the chromatographic device or by standalone temperature controlling electronics. The thermal modulator described herein contains an element for temperature modulation of the capillary column assembly to which it is attached and a temperature sensing element for providing accurate temperature feedback to the controlling electronics. The overall result of this when coupled to a chromatographic device is maximally efficient chemical separations in a small space with minimal power consumption.

The invention discloses a method for analyzing a residual quantity of a solvent in a compound by GC (Gas Chromatograph). The method comprises the step of carrying out separation by adopting the following chromatographic conditions: a detector is a hydrogen flame ionization detector, the temperature of the detector is 200 DEG C to 300 DEG C and is preferably 300 DEG C, and the temperature of an injection opening is 180 DEG C to 250 DEG C and is preferably 220 DEG C; a chromatographic column is a medium-polarity capillary gas chromatography column and adopts a programmed temperature process of keeping the temperature of 40 to 60 DEG C for 3 to 10min, then heating to the temperature of 100 to 140 DEG C at a speed of 5 to 15 DEG C / min, keeping the temperature of 100 to 140 DEG C for 1 to 10min, heating to the temperature of 200 to 230 DEG C at a speed of 15 to 25 DEG C / min and keeping the temperature of 200 to 230 DEG C for 1 to 20min; carrier gas is nitrogen, hydrogen or argon and is preferably nitrogen, and the flow rate of the carrier gas is 1ml / min to 10ml / min and is preferably 3ml / min; the solvent is selected from one or more of C1 to C6 carboxylic acid, methanol, ethanol, acetonitrile, ethyl acetate, tetrahydrofuran, methylbenzene and N,N-dimethylformamide; the C1 to C6 carboxylic acid is preferably C1 to C4 carboxylic acid and is more preferably acetic acid. When the method is adopted to detect the residual quantity of the solvent, the operation is simplified, time is saved and cost is saved.

In a fast gas chromatograph (GC) method and device for obtaining fast gas chromatography analysis, a capillary gas chromatography column is inserted into a resistively heated metal tube located mostly outside a standard gas chromatograph oven, which may serve as a heated transfer line to a flexible column that enters the resistively heated metal tube from its injector and exits into its detector. The fast GC device enables less than one minute full range temperature programming and cooling back analysis cycle time. The fast GC according to one embodiment is combined with mass spectrometry with supersonic molecular beams for the provision of fast analysis cycle time together with highly informative mass spectral information for improved sample analysis and identification.

The invention provides a method for analyzing tobacco flavor components by adopting a multi-dimensional hyphenated chromatographic technique. The method comprises the following steps: 1. extracting the tobacco flavor components; and 2. carrying out liquid chromatography-capillary gas chromatography / mass spectrometry (LC-CGC / MS) online segregation analysis on the tobacco flavor components: A. carrying out normal phase LC segregation on the tobacco flavor components; B. storing the LC effluent components in sample loops of multiposition valves of interfaces respectively; and C. after collection of the LC effluent components is completed, ensuring the fractions stored in the sample loops of the multiposition valves to be driven by carrier gases to respectively enter into a GC / MS to undergo segregation analysis by controlling ten-way valves in the interfaces of the hyphenated instruments. The method has the following prominent advantages: the tobacco flavor components can be segregated in advance through LC, the segregated components are respectively stored in the sample loops by online coupling interfaces and then the components respectively enter into the GC / MS to undergo accurate qualitative and quantitative analysis according to difference of the boiling points. The method not only has better orthogonal segregation property, but also has higher chromatographic peak capacity and better resolution and has simple operation steps.

The invention relates to a novel beta-cyclodextrin derivant capillary gas spectrum chiral fixed phase and relative preparation. The invention is characterized in that the invention leads allyl group with two keys into 2 and 3 positions of beta-cyclodextrin molecule, and leads valeryl group, enanthoyl group or caprylyl group into 6 position of beta-cyclodextrin molecule, to obtain novel beta-cyclodextrin detrivant. The inventive detrivant can be used as chiral fixed phase of capillary gas spectrum, with some chiral recognize ability to separate antimer of chiral compound.

Improved operating modes of a micro counter-current flame ionization detector (μFID) are demonstrated. By operating the flame inside the end of a capillary gas chromatography (GC) column, the effective cell volume enclosing the flame is considerably reduced and results in significantly lower gas flows being required to produce optimal sensitivity from the stable flame. In a post-column μFID arrangement, a very lean flame is now situated on the end of a stainless steel capillary delivering 10 mL / min of hydrogen, which is opposed by a counter-current flow of only 20 mL / min of oxygen. The μFID detection limit obtained in this stable, oxygen-rich counter-current flame mode is 7×10−11 gC / s with a response that is linear over 6 orders of magnitude. These findings are comparable to those of a conventional FID. Overall, the results indicate that the low-flow sensitive μFID operating modes presented demonstrate that this detector may be potentially useful for further adaptation to portable devices and related GC applications.

The invention relates to a method for preparing condoms, in particular to a method for preparing latex condoms. The method for preparing latex condoms comprises preparation of raw materials, a modeling process, a demolding process, a washing process, a post-curing process and an electrical inspection process, wherein the cleaning solution in the washing process comprises the following components in percentage by mass: 0.5 to 5 percent of borax, 1 to 8 percent of fruit acid, 2 to 9 percent of vitamin C, 1 to 8 percent of cellulose, 1 to 3 percent of silicon dioxide, 0.2 to 3 percent of alkylbenzene sulfonic acid, 0.1 to 3 percent of guar gum, 0.2 to 2 percent of sodium metasilicate pentahydrate, and the balance of soft water up to 100%. Detection through high-performance liquid chromatography and capillary gas chromatography-mass spectrometry proves that the latex condoms prepared according to the method is less than 0.01 mg / kg in remaining N-nitrosamines of nitrosamines, thereby having use safety and reliability and greatly reducing carcinogenic risk.

The invention discloses a metal-organic frameworks (MOFs) material-based series molecular sieve and a preparation method and an application method thereof in complex sample purification and separation analysis, and relates to the technical field of chromatography application and the field of solid phase micro extraction. The series molecular sieve comprises an MOFs material-based solid phase micro extraction device and an MOFs material-based capillary gas phase chromatographic column; the MOFs material-based solid phase micro extraction device comprises a section of stainless steel fiber extraction head, the surface of which is coated with an MOFs material; and the MOFs material-based capillary gas phase chromatographic column comprises a section of capillary, the inner wall of which is uniformly coated with a layer of MOFs material. High-selectivity purification, efficient separation and specificity detection and measurement of a complex sample are realized by combined use of the solid phase micro extraction device coated with the MOFs material and the gas phase chromatographic column coated with the MOFs material. The series molecular sieve is favorable for large-scale popularization and application, and has broad application prospect in the fields of analytical chemistry, particularly environmental analysis, food analysis and the like.

This invention relates to a capillary column solid phase coated with extraction phase micro extraction method and the device used with the analysis device, which comprises the following: one capillary solid phase micro extraction column with inner wall coated with solid phase, one six-way valve, extraction column heating box and transmission tube with desorption sample, micro three-way valve, micro air-extracting pump and assistant gas. The sample enters the extraction column under the assistant gas and micro air-extracting pump. After the flow and extracting of the sample, it rotates the six-way valve and immediately starts extraction column heating box to rapidly heat the capillary solid phase micro extraction column.

It relates to a single wall carbon nanometer quartz capillary column in the field of chromatographic separation of the analytical chromatograph. It is made of quartz capillary, and single wall carbon nanometer tube formed on the quartz capillary tube wall through chemical bonding method. It comprises three making processes: pretreatment of the quartz capillary column, amino propyl bonding, and the making of single wall carbon nanometer quartz capillary tubes. It is simple, easy for operation, with increased separation performance of the fixing liquid of inside the capillary gas chromatography.

Disclosed are deactivated surfaces for use in chromatographic separations, such as capillary gas chromatography, comprising a surface material coated with a deactivating polymer comprising high surface energy-generating groups and groups for end-capping reactive silanols. Also disclosed are columns comprising such surfaces, methods of making and using the surfaces, and kits for facilitating the same.

The invention relates to a method of detecting evaporable carbonyl compounds in cigarette filters by the solid-phase extraction and capillary gas chromatography. The cigarette filter is added with the Hydrochloric acidified 2,4-dinitrophenylhydrazine solution, for vibrating and extracting, then the extracted liquid is moved to C18 solid phase extraction columnella, eluted by cyclohexane, and the elutriant analyzed by GC, DB-5MS capillary chromato bar is adopted. The volume of sample injection is 1MuL. N2 is used as carrier gas in splitless sample injection. The flow rate of carrier gas is 1-2.5mL / min and the temperature of injection port is 200-250 DEG C. FID detector and the temperature of detector is 250 DEG C. The heating process is to keep initial temperature at 100 DEG C for 0-1min and heating rate at 15-20 DEG C / min, to 200 DEG C for 5min, then the heat rate from 4-8 DEG C / min, heating to 250 DEG C, keeps the temperature under 250 DEG C for 10min, quantitative analysis is according to the peak area. The invention lowers the operation request and can eliminate interference of nontaget compound which can separate formaldehyde, butanone, acrolein, crotonaldehyde, n-butylaldehyde, acetone, acetaldehyde from the cigarette filters effectively and quantitative analysis the seven evaporable carbonyl compounds in the cigarette filter accurately.

The invention relates to a thermal cracker, a thermal cracking gas chromatograph and a thermal cracking analysis method, which relate to the technical field of thermal cracking gas chromatography. The thermal cracker comprises a sample feeding device, a thermal cracking chamber, an electrical heating furnace, a carrier gas circuit and a control system, wherein the sample feeding device is connected with the thermal cracking chamber; the carrier gas circuit is connected with the upper end of the thermal cracking chamber; the electrical heating furnace is arranged at the periphery of the thermal cracking chamber; a sample carrying element is arranged in the thermal cracking chamber; the sample feeding device comprises a sample cup for containing a sample to be tested and a control button; and the control system is connected with the electrical heating furnace and used for controlling the temperature and the time of the electrical heating furnace. The sample feeding passage of the sample feeding device of the thermal cracker is vertical to a horizontal plane, so that secondary reaction can be minimized, the reproducibility of a chromatogram can be ensured, and the difference caused by manual operation can be eliminated maximally. The thermal cracking gas chromatograph comprises a capillary gas chromatographic column, wherein the outlet of the thermal cracker is connected with the capillary gas chromatographic column.

The invention relates to a preparation method of a hollow capillary tubular gas chromatographic column in a GDX porous polymer series. The method comprises the following steps that (1), HF is used for washing the inner wall of an elastic capillary tubular column in a dripping mode, then blowing is carried out, and a pre-processed elastic capillary tubular column is obtained; (2), polymer micro-sphere seed suspension liquid is prepared; (3), the two ends of the pre-processed elastic capillary tubular column are connected with buffer columns respectively, then the polymer micro-sphere seed suspension liquid is pressed into the buffer columns through nitrogen, and an elastic capillary tubular column of which the inner wall is coated with polymer seeds is obtained; (4), a polymerization reaction monomer suspension liquid is prepared; (5), the polymerization reaction monomer suspension liquid and a cross-linking agent are evenly mixed according to a proportion, and then stable suspension liquid is obtained; (6), the stable suspension liquid is pressed into the elastic capillary tubular column of which the inner wall is coated with the polymer seeds through nitrogen, after a coating is deposited in a water bath and then is blown dry, and then a hollow capillary tubular chromatographic column is obtained; (7), chromatographic column aging processing is carried out on the hollow capillary tubular chromatographic column, and chromatographic column testing evaluation is carried out after aging processing is finished. The method is low in column loss and stable in performance.

The invention discloses a method for simultaneously determining contents of various preservatives in soy by a capillary gas chromatography internal standard method, which comprises the following steps of: (1) weighing a soy sample; (2) adding an internal standard solution in the sample, and then sequentially being subjected to acidification, ether extraction, water removal water by purification and concentration treatment to obtain a sample solution; (3) taking the sample solution from the step (2) to be subjected to gas chromatography to obtain chromatographic data; and (4) comparing the chromatographic data obtained from the step (3) with the preset standard data of preservatives to obtain the contents of various preservatives in the soy. The method can simultaneously determine the contents of preservatives such as benzoic acid, sorbic acid, dehydroacetic acid and paraben esters and the like in the soy, is simple and convenient to operate, and is easy to implement, the impact of operation error, instrument conditions and other factors on determination results can be effectively reduced, and the results are accurate and reliable.

The invention discloses beta-ketone enamine chiral COFs (covalent organic frameworks) as well as a preparation method and an application of a bonded capillary gas chromatographic column prepared fromthe same. The beta-ketone enamine chiral COFs have advantages of high thermal stability, large specific surface area and uniform pore diameter distribution and can be applied to chiral recognition andseparation. The beta-ketone enamine chiral COFs and the bonded beta-ketone enamine chiral COFs capillary column prepared from the same can realize separation of mixed components of straight-chain paraffin and branched paraffin or mixed components of ethylbenzene and styrene and have good application prospects.

The invention provides an electronic nose online analysis method in gas-sensitive-gas chromatography multi-perception information selection, fusion and fermentation / malodor processes. The electronic nose online analysis method is characterized in that: a gas sample injection single period T<0> is 300-600s, the detected gas sample injection time of a gas sensitive sensor array module is asynchronous from the detected gas sample injection time of a capillary gas chromatographic column module, the accumulated sample injection amount of the gas sensitive sensor array module is unequal to the accumulated sample injection amount of the capillary gas chromatographic column module, and the sensing information selection and the analysis time are synchronous; 3 sensing information, namely a steady-state voltage peak value, a peak-appearing time and an area under the curve, is selected by a computer control and analysis module from a single gas sensitive sensor time length 60s response curve, and21 sensing information, namely 10 maximum peak values, 10 retention times and 1 area under the curve, is selected from a time length T<0>-10s semi-separation chromatogram; a modular deep convolutionneural network is utilized by the electronic nose instrument to realize long-term online detection and analysis of 5 fermentation tanks or malodor pollution points with the maximum cycle period of T=5T<0>, including odor type identification, overall odor intensity and main component concentration quantitative prediction.

The invention relates to a method for determining the residual quantities of organic solvents in temozolomide hexyl ester through capillary gas chromatography. The method comprises the following steps: 1, preparing internal standard solutions; 2, preparing contrast solutions; 3, preparing a tested object solution; and 4, injecting the above solutions to a chromatograph respectively to obtain chromatograms, and calculating according to the chromatograms to obtain the component kind and content of the organic solvents in the tested object solution.

A measurement method for contribution rate of commingled production crude oil capacity utilizes the capillary gas chromatography hydrocarbon finger-print detection technology of the crude oil, performs analysis on the finger-print composition of hydrocarbon in the crude oil at the level of molecule, and reflects the composition and content of the hydrocarbon compound in the crude oil; measurable differences exist among the concentration of composition of each layer of crude oil (such as isoalkane, cyclane, and the like) in the chromatograph hydrocarbon finger-print. According to the method, the multiple inlets crude oil capillary gas chromatography hydrocarbon finger-prints are used together to deduce backwards to obtain the yield contribution ratio of crude oil of each layer, single-layered crude oil finger-print library (using single-layered test oil sample) is not required, and the method is economical and practical, and is simple and convenient to operate.

The invention provides a three-online analysis method for the similarity of white spirits. The three-online analysis method comprises the steps of respectively carrying out high-resolution gas chromatography analysis, gas chromatography / mass spectrometry analysis and comprehensive two-dimensional gas chromatography / mass spectrometry analysis on white spirit samples; determining the natures of the peaks of components of the white spirits by means of the gas chromatography / mass spectrometry analysis; carrying out quantitative analysis on an integral result of the peaks of the components of the white spirits by a high-resolution gas chromatographic method; next, carrying out similarity calculation according to a quantitative analysis result; and carrying out similarity comparison and judgment on different batches of white spirits or true and false white spirits. The three-online analysis method for the similarity of the white spirits, provided by the invention, is used for performing separation analysis on the components of the white spirits through a high-resolution capillary gas chromatography; compared with a national standard method, the three-online analysis method has the advantages that the separated components are increased doubly and more detailed component information is provided. The reliability of the three-online analysis method is greatly superior to that of nature determination of a traditional mixed standard sample for a gas chromatography, the unique components of different kinds of white spirits can be identified, and detailed component analysis can be provided through identifying the true and false white spirits by a similarity calculation method and combining a comprehensive two-dimensional gas chromatography / mass spectrometry analysis method.

The invention belongs to the field of analytical chemistry detection, and relates to a method for detecting valsartan and content of N-nitrosodimethylamine in the preparation thereof. The detecting method comprises the steps of: grinding an object under test and weighing fine powder; adding a polar organic solvent in the powder and filtering by a filter membrane to prepare a solution under test; preparing a standard curve solution; acquiring a standard chromatogram map and a regression equation; detecting the solution under test by a gas chromatography-thermal energy analyzer to acquire a chromatogram map of the solution under test; if a chromatographic peak corresponding to the chromatographic peak in a standard curve chromatogram map exists in the chromatogram map of the solution under test, showing that the solution under test contains the N-nitrosodimethylamine; and calculating to acquire the concentration of the N-nitrosodimethylamine according to the area of the chromatographic peak in the chromatogram map of the solution under test. The principle of the method is reliable; the experimental operation is simple; the measuring precision and accuracy are ensured by using the high-separation efficiency of the capillary gas chromatography and the high-selectivity and the high-sensitivity of the thermal energy analyzer; and thus, the analysis time and test cost are greatly saved.

The invention relates to a capillipedium parviflorum essential oil, which is separated from capillipedium parviflorum inflorescence. In the separating process, the inflorescence of the capillipedium parviflorum is used as raw materials. The faint yellow oily essential oil concentrated solution is acquired by using the conventional method which includes the steps of collecting, washing, normal-pressure steam distillation, oil-water separation and drying with anhydrous sodium sulfate. The oil yield is 0.8% to 1%. The dried essential oil is determined by using a capillary gas chromatograph-mass spectrometer. The result is that the type number of the compound is 22 which is 92.75% of the whole oil mass, wherein the primary component is 1-nonene-4-alcohol, 4-hendecanone, 4-undecanol, and 2,4-dimethyl-3-pentyl acetate. The essential oil is high-class pure natural essential oil which is fragrant, stable in fragrant, good in inducing property, free from stimulation to skin, non-toxic and safe, and is capable of being used for preparing cosmetics, used as food additives, tobacco essence, washing agent essence and officinal essence.

The invention relates to a preparation method and application of a polycaprolactone glycol capillary gas chromatographic column. A polycaprolactone glycol polymer is used as a capillary gas chromatographic stationary phase, and the polymer is smeared onto the inner wall of an elastic molten quartz capillary which is pre-roughened by utilizing sodium chloride and methanol suspension by virtue of a static method. The obtained capillary column is high in column efficiency, good in inertness and good in heat stability, can be used for separating components different in polarity such as aliphatic and aromatic hydrocarbons, alcohols, ketones, aldehydes, amines and phenols, and positional isomers of the components, is particularly suitable for effectively separating the isomers which are difficult to separate such as dimethylbenzene, toluidine and methylphenol and has good application prospect.

The invention discloses a capillary gas chromatography chiral column based on a chiral organic molecular cage material, which is prepared by the following steps: firstly, synthesizing the chiral organic molecular cage material, dissolving the chiral organic molecular cage material in a volatile organic solvent to prepare a solution, mixing the solution with a polysiloxane solution to obtain a stationary phase, and preparing the capillary gas chromatography chiral column by adopting a static column preparation method. The prepared chromatographic column shows excellent chiral resolution performance on a plurality of chiral compounds including alcohol, dihydric alcohol, halogenated hydrocarbon, epoxy compounds, esters, lactones, ketones, ethers, organic acids and the like. The chromatographic column disclosed by the invention is applied to gas chromatography resolution of the chiral compounds, has the remarkable characteristics of simple preparation method, cheap raw materials, good stability, reusability, excellent chiral resolution performance and the like, and has a very good application prospect.

The present invention discloses a method for determining (4R, 6R) -6--aminoethyl-2,2-dimethyl-1,3-dioxane-4- tert-butyl acetate content. The method is as follows: ATS-9 is diluted with 1,2-dichloroethane, an Agilent DB-624 capillary gas chromatography column is used, a hydrogen flame ionization detector is used, appropriate temperature programing, vaporization chamber temperature and detector temperature are set, nitrogen is used as a carrier gas, n-hexadecane is used as an internal standard for detection, and ATS-9 content in a to-be-tested solution can be calculated by internal standard method according to the gas chromatogram. The ATS-9 and related substances and the internal standard can be effectively separated, and the method is rapid, accurate, simple and well reproducible, and lays the foundation for the establishment of ATS-9 quality standards.

The invention relates to a method for determining the enantiomer ratio of trimethylcyclopentene derivatives of structure (I), wherein Z is an alkyl radical having 1-10 C atoms, can be saturated or olefinically unsaturated, straight-chained or branched and which is substituted by an OH or CHO group, by means of capillary gas chromatography, wherein a stationary phase is applied containing a compound selected from the group of Heptakis-(2,3-di-O-methyl-6-O-tert.-butyldimethylsily)-β-Cyclodextrin and Heptakis-(2,3-di-O-acetyl-6-O-tert.-butyldimethylsilyl)-β-Cyclodextrin and at least one polysiloxane, wherein the mixing ratio of Cyclodextrin derivatives and polysiloxanes is adjusted to a value ranging from 10:90 to 50:50.

The invention relates to an adulteration identification method for cod-liver oil. The adulteration identification method comprises the following steps: performing peak area determination on fatty acidin the cod-liver oil and fish oil for adulteration by adopting precolumn derivatization capillary gas chromatography, calculating the percentage of typical fatty acid relative to total fatty acid according to an area normalization method and establishing a threshold, wherein the threshold of vegetable fatty acid references to national standards; finding out fatty acid with characteristic indexesby comparing the threshold of the fatty acid in the cod-liver oil with that of the fatty acid in the oil for adulteration; rapidly identifying the adulterated fish oil in the cod-liver oil by establishing a two-dimensional adulteration model of characteristic fatty acid and drawing an adulteration identification analysis chart; rapidly identifying adulterated vegetable oil in the cod-liver oil byadopting linoleic acid in the vegetable oil as a characteristic index and analyzing and comparing the content of the linoleic acid in a sample with the threshold of the cod-liver oil. The adulterationidentification method based on the characteristic indexes of the fatty acids in the cod-liver oil, the fish oil and the vegetable oil, provided by the invention, has the characteristics of science, accuracy, simplicity and convenience.

The invention relates to a capillary column gas chromatography method for an N-methyldiethanolamine decarbonizer component. Gas chromatography conditions of the method comprise: a column temperature of 280 DEG C; an introduction port temperature of 270 DEG C; a detector temperature of 320 DEG C; a column flow rate of 1.03 mL / min; and a split ratio of 49:1. Heating procedures of the column temperature comprise: maintaining a temperature of 80 DEG C for 0 min; then heating to a temperature of 100 DEG C at a rate of 10 DEG C / min and maintaining the temperature of 100 DEG C for 0 min; heating to a temperature of 150 DEG C at a rate of 20 DEG C / min and maintaining the temperature of 150 DEG C for 0 min; and heating to a temperature of 280 DEG C at a rate of 50 DEG C / min and maintaining the temperature of 280 DEG C for 0 min. The gas chromatography conditions further comprise: a make-up flow velocity of 30 mL / min, a hydrogen flow velocity of 40 mL / min and an air flow velocity of 400 mL / min, The method provided by the invention is accurate, sensitive, easy and convenient, has high separation efficiency, does not need derivatization and pretreatment, shows a fast analysis speed and can totally satisfy quality inspection requirements of actual production in the process of production quality inspection in a factory.

The invention relates to a vaporizer tube for vaporizing liquid samples in capillary gas chromatography. The vaporizer tube is open throughout its whole length. It has throats which are shaped to provide, in their region, a heavy increase of the flow velocity of the carrier gas, which flows substantially unrestrictedly through the vaporizer tube. This increase of the flow velocity causes, in accordance with Bernoulli's law, reduction in pressure. Due to this pressure reduction, the easily volatile solvent is predominantly volatilized. This vaporized solvent is carried along by the carrier gas flow. The solvent can then be removed through an outlet of the sample inlet chamber. The sample proper is vaporized in the larger diameter, low velocity zones between the throats by heating the vaporizer tube and are fed to the capillary column, after the solvent has been volatilized. Thus the vaporizer tube with a plurality of throats acts like a multi-plate column.

The invention relates to a method for detecting the residual quantity of N, N-dimethyl formamide in PU (Polyurethane) leather. The method comprises the following steps: S1, leaching N, N-dimethyl formamide in the PU leather by using an ionic liquid to obtain an ionic liquid extracting liquid, wherein the ionic liquid is a liquid ionic liquid at room temperature; and S2, detecting N, N-dimethyl formamide in the ionic liquid extracting liquid obtained in the S1 by using a head space capillary gas chromatography-mass spectrum combination technology so as to convert to obtain the content of N, N-dimethyl formamide in the PU leather. According to the method, the novel green solvent namely the liquid ionic liquid at room temperature is selected as the extracting agent to extract DMF (Dimethyl Formamide) in the PU leather, and the head space capillary gas chromatography-mass spectrum combination method is directly used to analyze the content of DMF in the extracting liquid, so that the detection method provided by the invention is environment-friendly, simple to operate, good in reproducibility, high in recovery rate and high in accuracy.