340 results about "Vapor phase chromatography" patented technology

The invention discloses a method and a system for identifying mixed gas in transformer oil, a product and a medium, and relates to the technical field of testing or analyzing materials by means of measuring chemical or physical properties of the materials, and the method comprises the following steps: acquiring an internal structure diagram of a transformer, determining spatial position relations of parts and corresponding temperature distribution characteristics, and obtaining solubility differences of different spatial positions according to the spatial position relations and the corresponding temperature distribution characteristics. During operation, mixed gas concentration data of a plurality of detection points are collected, initial gas concentration data are recorded when an operation threshold range is deviated, and gas concentration change data are corrected according to solubility differences of different temperature zones. Calculating gas concentration space-time distribution characteristics, and determining a gas accumulation area according to the gas concentration space-time distribution characteristics and a space position relation. And separating the mixed gas components by using a gas chromatographic method, comparing preset gas types with the content of each component, and determining the corresponding gas type of each internal region. By implementing the method, the accuracy of identifying the types of the mixed gas in the transformer oil can be improved.

The invention discloses a method for detecting ethylene oxide and acetonitrile in stationary source waste gas, which comprises the following steps: collecting the stationary source waste gas according to a waste gas sampling device, and researching the movement direction of the stationary source waste gas to obtain movement characteristics; carrying out ethylene oxide and acetonitrile detection on the stationary source waste gas by adopting a gas chromatographic method according to the motion characteristics to obtain first detection data; carrying out ethylene oxide detection on the stationary source waste gas by adopting an electrochemical analysis method, and carrying out acetonitrile detection by adopting a liquid chromatography to obtain second detection data; and performing data fusion on the first detection data and the second detection data to obtain a comprehensive quantity, and outputting the comprehensive quantity as a detection result. The method not only can improve the detection precision of the ethylene oxide and the acetonitrile in the stationary source waste gas, but also has better interpretability, and can be directly applied to a detection system of the ethylene oxide and the acetonitrile in the stationary source waste gas.

Improved gas sample preprocessing is provided for scanning optical spectroscopic analysis instruments by tailoring characteristic gas handling times to the scan time Ts of the analysis instrument. In particular, for sample preconcentration, the desorption duration Td of the sample preconcentrator should be ≥2Ts. For gas chromatography, the elution duration Te of relevant eluted species should be ≥2Ts. This advantageously avoids having significant changes in the gas sample within the analysis instrument as a scan is being performed.

The invention relates to a method for simultaneously detecting three related substances in an olpinapone starting material. According to the detection method, the three related substances in an opinapone starting material are simultaneously detected by using a gas chromatographic method of a hydrogen flame ionization detector. According to the detection method, the problem that three related substances cannot be detected simultaneously due to weak ultraviolet absorption and large difference under the liquid chromatography condition can be solved, the matrix effect generated by an opiapone starting material under the gas chromatography condition can be eliminated, the condition that the separation degree of the three related substances is poor is improved, and the detection accuracy is improved while the detection efficiency is improved. And the true and reliable quality of the initial material of the olpinapone is also ensured. The method can be used for simultaneously and quantitatively detecting three related substances higher than 0.02% in the initial material of the opinapone, and is high in sensitivity, good in separation degree, high in practicability and simple and rapid in detection process.

The invention discloses a method for detecting a chiral isomer of 6-hydroxy-8-chloro ethyl caprylate. The method comprises the following steps: carrying out gas chromatography detection on a test solution containing R-6-hydroxy-8-chloro ethyl caprylate and S-6-hydroxy-8-chloro ethyl caprylate, wherein the gas chromatography detection is carried out on the test solution containing R-6-hydroxy-8-chloro ethyl caprylate and S-6-hydroxy-8-chloro ethyl caprylate; the conditions of the gas chromatography detection are as follows: a chromatographic column is selected from a chiral chromatographic column containing beta-cyclodextrin; the chromatographic column adopts programmed heating in the detection process, the initial column temperature is 120-180 DEG C, the final column temperature is 190-220 DEG C, and the heating rate is 0.5-2.0 DEG C / min. The method is based on a gas chromatographic method, adopts a beta-cyclodextrin-containing chiral chromatographic column, and is combined with programmed heating at a specific initial column temperature heating rate, so that the two chiral isomers of 6-hydroxy-8-chloro ethyl caprylate can be separated and detected, the sensitivity is high, the specificity is good, and the separation degree meets the standard; the method has important significance on preparation of single-configuration lipoic acid.

Improved gas sample preprocessing is provided for scanning optical spectroscopic analysis instruments by tailoring characteristic gas handling times to the scan time Ts of the analysis instrument. In particular, for sample preconcentration, the desorption duration Td of the sample preconcentrator should be ≥2Ts. For gas chromatography, the elution duration Te of relevant eluted species should be ≥2Ts. This advantageously avoids having significant changes in the gas sample within the analysis instrument as a scan is being performed.

Methods and systems for carrier gas identification in gas chromatography are described herein. In one aspect, a gas chromatography system can include a pneumatic system including an input flowpath in fluidic communication with a first output flowpath and a second output flowpath; a first flow sensor configured to generate a flow measurement signal corresponding to a first property of a gas; a second flow sensor configured to generate a second flow measurement signal corresponding to a second property of the gas different than the first gas property; and a controller programmed to: determine the first flow measurement signal for the flow of gas through the pneumatic system; determine the second flow measurement signal for the flow of gas through the pneumatic system; and identify a type of gas for the flow of gas through the pneumatic system from the first and second flow measurement signals.

A method for evaluating an unknown gas sample includes acquiring a chromatogram of the unknown gas sample and processing the chromatogram to identify a peak. The peak is evaluated to determine if it is representative of a single gas species in the unknown gas sample. The peak is fit with at least first and second curves when the peak is not representative of a single gas species. First and second areas under the corresponding first and second curves are computed and processed to compute a composition of the unknown gas sample or a ratio of concentrations of individual gases in the unknown gas sample.

The invention belongs to the technical field of analysis and detection, and relates to an analysis method and an analysis system of ethylene glycol by-product mixed alcohol, the analysis method comprises the following steps: S1, preparing a corresponding reference solution and a standard mixed alcohol solution according to a to-be-analyzed component in the ethylene glycol by-product mixed alcohol; s2, for the reference substance solution and the standard mixed alcohol solution, constructing a standard curve model corresponding to each component through gas chromatography; s3, collecting by-products in ethylene glycol production in real time, and filtering; according to the method, peak areas corresponding to components to be analyzed in the mixed alcohol sample are obtained and then substituted into respective standard curve models respectively, and the content of the components to be analyzed in the mixed alcohol sample is obtained. According to the method, the standard curve model is constructed, and the mixed alcohol is pretreated, so that the content of multiple components in the mixed alcohol is analyzed and detected, the analysis time is shortened, the analysis cost is reduced, and the analysis accuracy and sensitivity are improved.

The invention relates to the technical field of detection methods, and discloses a method for determining the content of triterpene alcohol in camellia oil, which comprises the following steps: (1) saponifying and extracting a camellia oil sample, and loading on a machine to be detected; then carrying out silanization derivation treatment, and loading to be detected again; (2) beta-amyrin, butyryl whale alcohol and lupeol are respectively prepared into standard solutions, the standard solutions of the beta-amyrin and the butyryl whale alcohol are directly put on a machine to be detected, and the standard solution of the lupeol is put on the machine to be detected after being subjected to silanization derivation treatment; (3) gas chromatography detection: the temperature rise mode of the column temperature is that the temperature is kept at 180-190 DEG C for 1-5 min, then the temperature is raised to 260-300 DEG C at the rate of 10-15 DEG C / min, and the temperature is kept for 20-40 min; the split ratio is (20-40): 1. According to the method, the triterpene alcohol is measured by adopting a gas chromatography external standard method, and the result is more scientific, advanced, accurate and reliable.

The invention relates to the field of chemical testing, in particular to a method for measuring the purity of an acrylonitrile raw material, which comprises the following steps: preparing and calibrating a standard solution, weighing a sample, transferring the sample, carrying out sample titration analysis, carrying out blank titration analysis and calculating a result, thereby obtaining the purity of the acrylonitrile raw material. According to the method, the problems of high cost and overlong detection time of instruments required for detecting the purity of acrylonitrile by a gas chromatographic method are solved, the volatilization loss caused by sample transferring is avoided, the detection efficiency and the test accuracy are improved, and the real purity value of acrylonitrile can be reflected more accurately.

Gas chromatography (GC) relies on the interaction of vapor molecules with the stationary phase coated on the column inner wall to separate different vapor molecules. Here, graphene is integrated as the ultrathin and electrically tunable stationary phase within a GC column. Graphene has different interactions with different vapor molecules, which leads to separation of those vapor molecules. In addition, by configuring graphene into a field effect transistor (FET) design, the molecule-graphene interaction can be controlled or tuned by adjusting the graphene Fermi level through the FET gate voltage. As a result, the binding energy between graphene and adsorbed vapor molecules can be tuned and hence the elution time and / or elution order of vapor molecules can be changed.

The invention discloses a method for calculating the molar substitution degree of hydroxyethyl starch by applying a nuclear magnetic resonance carbon spectrum, and belongs to the technical field of analysis and detection. The method comprises the following steps: carrying out nuclear magnetic resonance test on a sample to be detected to obtain a nuclear magnetic resonance 13C spectrum, and determining the molar substitution degree of hydroxyethyl starch according to the peak integral ratio of hydroxyethyl alpha carbon or beta carbon in hydroxyethyl starch glucose to glucose 1-position heterogenous carbon; compared with a traditional Morgan method and a traditional gas chromatography method, the method has the advantages that the operation process is simplified, time and labor are saved, the consumption of experimental consumables and reagents is greatly reduced, the molar substitution degree can be intuitively calculated on the basis of not damaging the structure of a sample, and the method is simpler, more convenient, high in accuracy, simple and convenient to operate and high in detection speed; the method can be used for detecting the molar substitution degree of hydroxyethyl starch.

The invention discloses a method for determining the content of various residual solvents in a clozapine bulk drug by using capillary gas chromatography, and belongs to the technical field of drug analysis. According to the method, a gas chromatographic method is adopted, a capillary chromatographic column with 6% of cyanopropyl phenyl-94% of dimethyl polysiloxane as a stationary liquid is adopted, an FID detector is adopted for detection, and the content of the residual solvent is calculated by peak area according to an external standard method; wherein the multiple residual solvents are methanol, ethanol, isopropanol, n-amyl alcohol, n-butyl alcohol and toluene. The method disclosed by the invention is good in specificity, good in linearity, reliable in accuracy and high in sensitivity; the gas chromatographic method can be used for rapidly, effectively, accurately and reliably separating and detecting the content of various residual solvents in the clozapine raw material medicine, the product quality of the clozapine raw material medicine is improved, and the medication safety of a patient is improved.

The invention relates to the field of medicine detection, and particularly provides a method for detecting the residual content of triethanolamine by ion exchange-high performance liquid chromatography, and the chromatographic conditions in the method are as follows: a chromatographic column adopts a bonded cation exchange medium sulfonic group or carboxyl as a filler; a mobile phase is a phosphate buffer solution, and isocratic elution is carried out. According to the method disclosed by the invention, the triethanolamine does not need to be subjected to pre-column derivatization, and macromolecular protein and triethanolamine separation development (direct flow-through of macromolecular protein) is also not needed, so that the problem that the macromolecular protein is precipitated and removed to detect the triethanolamine when the gas chromatography is used is solved; and the problem that other detector modules such as a mass spectrum detector, an evaporative light detector and an electric conductivity detector need to be equipped and maintained is also solved. The method has the advantages of simple operation, accurate result, small interference and high sensitivity.

The invention belongs to the technical field of pharmaceutical analysis, and discloses a method for determining two potential genotoxic impurities in carbon [13C]-urea by gas chromatography. Comprising the following steps: (1) preparing a sample solution; (2) preparing a reference solution; (3) taking nitrogen as carrier gas, and detecting by adopting a medium-polarity or weak-polarity chromatographic column separation system; and (4) calculating by a peak area through an external standard method to obtain the accurate contents of methyl carbamate and ethyl carbamate in the carbon [13C]-urea. The method disclosed by the invention is simple to operate, good in specificity, linearity, precision and accuracy and high in sensitivity, and can realize accurate detection of residual potential genotoxic impurities, namely methyl carbamate and ethyl carbamate, in the carbon [13C]-urea.

A tricyclodecane dimethanol composition, comprising tricyclodecane dimethanols, wherein the tricyclodecane dimethanols comprise a chiral compound A, one of whose mirror image isomers is represented by the following formula (I), a chiral compound B, one of whose mirror image isomers is represented by the following formula (II), and a chiral compound C, one of whose mirror image isomers is represented by the following formula (III). In the composition, the sum of the peak area Xc of the gas chromatogram of the chiral compound C and the peak area Xt of the gas chromatogram of the tricyclodecane dimethanols detected by gas chromatography satisfies Xc / Xt≥0.35.

The invention discloses a method for simultaneously determining the content of nicotine, water, 1, 2-propylene glycol and glycerol and application of the method, and the method comprises the following steps: S1, taking a sample to be detected, and extracting to obtain extract liquor; s2, taking the extract liquor, and carrying out quantitative analysis on nicotine, water, 1, 2-propylene glycol and glycerol in the to-be-detected sample by adopting a gas chromatographic method, wherein the gas chromatography method comprises the following steps: taking nitrogen as carrier gas to bring the extract liquor into a capillary chromatographic column for separation, and dividing the separated gas into two paths, one path is subjected to FID detection, and the other path is subjected to TCD detection. According to the method, double detectors are adopted for detection, and nicotine, water, 1, 2-propylene glycol and glycerol can be accurately, efficiently and synchronously detected and analyzed through one-time sample introduction, so that time and labor are saved; the method is high in quantitative accuracy, good in precision, high in recovery rate and high in sensitivity, is particularly suitable for detection and analysis of large-batch samples, and has a good application prospect in the field of tobacco product quality control.

Systems and methods estimating the SARA fractions of a reservoir fluid. This method uses a machine learning (ML) based model to predict the SARA fractions of a reservoir fluid. The ML models are trained using conventional laboratory data, such as fluid composition from gas chromatography, SARA measurement, Asphaltene onset pressure (AOP) etc. Reservoir fluid can be pumped from a wellbore into a downhole fluid analyzer tool. The downhole fluid analyzer tool can take measurements indicating the presence and levels of certain particles in the fluid. The measurements can be applied to the ML models to estimate SARA levels in the reservoir fluid.

The invention discloses a gas chromatography method for determining the purity of methylsulfonyl fluoride. The gas chromatography method comprises the following steps: preparing a standard working solution and a test solution; respectively testing the standard working solution and the test solution by adopting a gas chromatographic method to obtain a standard working solution measurement result and a test solution measurement result; performing standard curve fitting on the measurement result of the standard working solution to obtain the function relationship between the methylsulfonyl fluoride mass and the methylsulfonyl fluoride peak area and the function relationship between the solvent mass and the solvent peak area; and calculating the purity of the methylsulfonyl fluoride in the test solution according to the test result of the test solution and the function relationship. The method is easy to operate, high in accuracy and good in stability, the chromatographic purity of the methylsulfonyl fluoride can be accurately measured, and the defect of a methylsulfonyl fluoride analysis technology is overcome.

The invention discloses a method for detecting triethylamine in cefazolin sodium, which comprises the following steps: carrying out gas chromatography detection in a headspace sampling manner, recording a chromatogram, and carrying out quantitative analysis on the chromatogram by adopting an external standard method. Wherein the chromatographic column is a capillary chromatographic column with methylpolysiloxane as a stationary phase or a gas-phase capillary chromatographic column with equivalent efficiency; the temperature of a sample inlet is 200 DEG C; the temperature of a detector is 250 DEG C; in the temperature rising procedure, the change range of the initial temperature ranges from 35 DEG C to 45 DEG C, the temperature is maintained for 10 minutes, and the temperature is increased to 200 DEG C at the speed of 20 DEG C per minute and maintained for 2 minutes. The detection method provided by the invention has good specificity and system adaptability, good sample injection precision, extremely low detection limit and quantitation limit, good durability, good linearity, good accuracy and very high sensitivity, and can be widely applied to quality control of the cefazolin sodium product.

The present invention belongs to the technical field of chemical production, and specifically relates to a sample pretreatment method for detecting the carbon content of titanium tetrachloride by high-temperature calcination, which solves the defect in the prior art that all carbon-containing substances cannot be analyzed and added up by infrared spectroscopy and gas chromatography, resulting in the influence on the accuracy of total carbon determination; the technical solution includes: weighing a certain mass of titanium tetrachloride and a Lewis acid, adding the Lewis acid to the titanium tetrachloride, heating and refluxing to precipitate the residual carbon in the titanium tetrachloride, collecting the residual carbon precipitate through a filtering instrument, and cleaning the filtering instrument with a suitable reagent to ensure complete separation of the titanium tetrachloride and the residual carbon. Then, the residual carbon is completely dried and the mass is recorded, and after drying, it is calcined at high temperature until complete and the mass is recorded. The carbon content of the titanium tetrachloride is calculated according to the mass loss before and after calcination and the mass of the weighed titanium tetrachloride.

The invention relates to the technical field of food detection, in particular to a method for determining the iodine content in formula food for special medical purposes. The determination method comprises the following steps: (1) weighing potassium iodide, and adding water for dissolving to obtain a reference substance working solution; (2) adding water into a test sample to obtain a sample suspension, and performing alkali ashing treatment to obtain a sample solution; (3) adding a sulfuric acid solution and a reagent adopted for alkali ashing treatment into the reference substance working solution, and respectively performing derivatization treatment and organic solvent extraction on the reference substance working solution and the sample solution to obtain a reference substance solution and a test solution; (4) testing by adopting a gas chromatographic method, and calculating the iodine content; reagents adopted in the alkali ashing treatment are a potassium hydroxide solution, a potassium nitrate solution and a potassium permanganate solution (or manganese dioxide); the derivatization treatment comprises the steps of adding a sodium sulfite solution, standing, and adding a ketone reagent and a hydrogen peroxide solution to carry out a derivatization reaction. The method has the advantages of being low in cost, high in safety and high in accuracy.

The invention discloses a method for detecting related substances of tribromoacetone by gas chromatography, which belongs to the technical field of chemical detection, the related substances of tribromoacetone are detected by gas chromatography, an instrument is a gas chromatograph, a detector is an FID detector, a capillary column taking 100% methylpolysiloxane (MEGA-1) as a stationary liquid is used as a chromatographic column, carrier gas is N2, the flow velocity is 2.0 mL / min, the split ratio is 50: 1, and the detection time is 30 minutes. Temperature programming: the initial temperature is 80 DEG C, and the temperature is raised to 250 DEG C at the rate of 10 DEG C per minute and maintained for 10 minutes; a sample injection mode is as follows: direct sample injection is performed, the temperature of a sample injection port is 260 DEG C, and the temperature of a detector is 280 DEG C; according to the present invention, the sample introduction volume is 0.2 [mu] l, the related substances in the tribromoacetone can be effectively separated, the content of the related substances can be quantitatively detected, the acetone, the bromoacetone, the 1, 3-dibromoacetone and the 1, 1, 3, 3-tetrabromoacetone sequentially appear peaks, and the method has characteristics of simple operation, strong specificity, good repeatability, good intermediate precision and good durability, and can accurately and rapidly determine the content of the various related substances in the tribromoacetone.

The present invention belongs to the field of analysis and detection, and specifically relates to a method for simultaneously detecting residual organic solvents of N,N-dimethylformamide and sulfolane in amifostine by gas chromatography, which includes sample pretreatment and gas chromatograph detection method, and the steps are as follows: take amifostine, first add water to completely dissolve it, then add an organic solvent to filter after amifostine is precipitated, and take the filtrate and directly enter the gas chromatograph according to the gas chromatography detection conditions. The sample pretreatment method of the present invention can not only completely dissolve the DMF and sulfolane wrapped in the amifostine sample, but also remove the high-boiling point amifostine and directly enter the gas chromatograph, avoiding the contamination of the gas chromatograph and the detection interference caused by the degradation impurities of amifostine. The gas chromatograph detection method provided by the present invention can simultaneously and accurately detect the content of residual organic solvents of N,N-dimethylformamide and sulfolane in amifostine.

The invention belongs to the technical field of medicine detection, and particularly relates to a method for determining enantiomers in a levocarnitine intermediate by gas chromatography. The method for determining the enantiomer in the levocarnitine intermediate by the gas chromatography comprises the following steps: taking a capillary column which takes dimethyl polysiloxane bonded with cyclodextrin as a stationary liquid as a chromatographic column; the method comprises the following steps: dissolving and diluting a test product (R)-4-chloro-3-hydroxy ethyl butyrate by using ethyl acetate, and deriving by adding acetic anhydride and pyridine to prepare a test product solution; and injecting the test solution into a gas chromatograph, recording a chromatogram, and calculating the content of the enantiomer (S)-4-chloro-3-hydroxybutyric acid ethyl ester in the levocarnitine intermediate (R)-4-chloro-3-hydroxybutyric acid ethyl ester according to an area normalization method. The method for determining the enantiomer in the levocarnitine intermediate by the gas chromatography provided by the invention is accurate and fast in detection, and provides a basis for quality control of levocarnitine.

The invention relates to a qualitative and quantitative detection method for difluoroethylene carbonate in electrolyte, which comprises the following steps: preparing a plurality of DFEC standard solutions, selecting a chromatographic column, setting test parameters of a gas chromatograph-mass spectrometer, and detecting the prepared DFEC standard solutions. Determining a standard curve, a detection limit and a quantitation limit according to the concentration of the standard solution and the detected peak area, and forming a standard curve equation according to the standard curve; detecting the pretreated to-be-detected electrolyte to obtain the peak area of the to-be-detected electrolyte, and searching according to the standard curve to obtain the concentration of the DFEC in the to-be-detected electrolyte, or calculating according to a standard curve equation to obtain the concentration of the DFEC; according to the method disclosed by the invention, high-sensitivity and high-selectivity detection on trace DFEC in the electrolyte is realized through the synergistic effect of the gas chromatography and the mass spectrum and setting of specific test parameters.

The invention discloses a method for determining the purity of tert-butyl-(S)-[2-(2-cyano-4, 4-difluoropyrrolidine-1-yl)-2-oxyethyl] carbamate, which adopts a gas chromatographic method, adopts a capillary column which takes (5%-phenyl)-95% methylpolysiloxane copolymer as a stationary liquid as a gas chromatographic column, and adopts a temperature rising procedure to detect the purity of tert-butyl-(S)-[2-(2-cyano-4, 4-difluoropyrrolidine-1-yl)-2-oxyethyl] carbamate. And after the sample introduction, calculating the purity of the tert-butyl-(S)-[2-(2-cyano-4, 4-difluoropyrrolidine-1-yl)-2-oxyethyl] carbamate according to a peak area normalization method, so as to obtain the tert-butyl-(S)-[2-(2-cyano-4, 4-difluoropyrrolidine-1-yl)-2-oxyethyl] carbamate. According to the method, the purity of Boc-Fapi-a is detected by adopting a gas chromatography temperature programming method, so that the influence of weak UV response signals and different response intensities of various impurity components can be avoided, the technical blank of lack of an effective chromatographic detection method for the substance at present is filled up, the convenient quality control is realized, and the detection requirement is met.

A working oil composition for shock absorbers, which contains the following components (A) and (B): (A) an ester base oil having a pour point of-45 DEG C or less and a 10% distillation temperature of 300 DEG C or more as determined by the gas chromatography distillation test method specified in JIS K 2254: 1998; and (B) zinc dialkyl dithiophosphate.

This invention relates to a bag-film laminate comprising a base layer, a gas barrier layer, and a sealant layer sequentially laminated together, wherein the amount of lubricant present on the surface of the sealant layer is 5 mg / m³. 2 Up to 25 mg / m 2 The surface roughness (Ra) of the sealant layer is 0.1 μm to 0.5 μm. The amount of lubricant is obtained by cutting the bag-film assembly into 100 mm × 100 mm sections in the MD direction and TD direction, dropping 5 ml of chloroform onto the surface of the sealant layer of the bag-film assembly and letting it stand for 1 minute to prepare a lubricant extraction solution, and then using gas chromatography to measure the amount of lubricant contained in the lubricant extraction solution.