1214 results about "Vapor phase chromatography" patented technology

Microwave assisted synthesis may be used to produce water-repellent metallic organic frameworks (MOFs) molecules. The water-repellent MOFs contain non-polar functional groups, such as a trifluoromethoxy group, which has a strong water repellent effect. The water-repellent MOF, when exposed to water vapor for one week does not result in a significant X-ray power pattern change. The water-repellent MOFs may be suitable as an adsorbent in many industrial applications, such as gas chromatography.

The basic structure of a PTV (programmed temperature vaporizer) injector has been considerably modified so that is can be used for the direct coupling of liquid chromatography in normal phase or reverse phase, and gas chromatography and also for the introduction of high volumes in gas chromatography. The glass tube of the injector is filled with an adsorbent. By means of a system of valves and tubes or capillary tubes, the previously selected fraction of liquid chromatography is transferred to the injector, said fraction coming in through the same extremity for introducing the gas chromatography column. The eluent is entrained by a gas stream through the adsorbent, wherein are retained the solutes, and the solvent is removed through a tube or capillary tube introduced in the injector through the opposite extremity. Thereafter, the solutes are desorbed thermally passing to the chromatography column.

An on-line quickly sampling and sample feeding device of multichannel gas consists of gas sampling unit formed by gas pipeline, multiple solenoid valves and a microdiaphragm vacuum pump; an fully-automatic six-way valve for feeding gas sample automatically; pipeline washing unit formed by a gas washing bottle and multiple solenoid valves; control unit formed by multiple switches being controlled manfully or being controlled automatically by computer .The property evaluating system of catalyst by utilizing said device is also disclosed .

A novel gas injection valve for injecting discrete charges of gas into a mobile phase or carrier stream is provided. Injection valves of the invention comprise a plurality of microvalves capable of receiving gas at different pressures and emitting discrete charges of gas at approximately the same pressure. The invention further provides for parallel injection valve arrays capable of injecting multiple samples substantially simultaneously and a method of injecting discrete gas samples at a controlled pressure to a high-resolution gas chromatograph.

The invention relates to a method for detecting multiple residual solvents in a medicament. According to the method, by utilizing a gas chromatographic method, nine organic solvents including methanol, ethanol, acetonitrile, acetone, isopropanol, methylene dichloride, ethyl acetate, tetrahydrofuran and triethylamine in the medicament are simultaneously detected, the sensitivity and the precision are high, and the repeatability is good; by utilizing a standard addition method, other standard substances do not need to serve as internal standard substances, only pure substances of to-be-measured components are needed, the accuracy requirement on the sampling volume is low, and the operation is simple; by utilizing a headspace sampling method, a direct solution sample is prevented from interfering the detection and polluting a chromatographic column; by utilizing a temperature programming method, low-boiling-point organic solvents and high-boiling-point organic solvents can be effectively separated.

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

Method and apparatus for chromatographic high field asymmetric waveform ion mobility spectrometry, including a gas chromatographic analyzer section intimately coupled with an ionization section, an ion filter section, and an ion detection section, in which the sample compounds are at least somewhat separated prior to ionization, and ion filtering proceeds in a planar chamber under influence of high field asymmetric periodic signals, with detection integrated into the flow path, for producing accurate, real-time, orthogonal data for identification of a broad range of chemical compounds.

The present invention concerns a new and useful structure for forming a capillary tube, e.g. for gas chromatography, and methods for forming the capillary tube are described. The capillary tube comprises a tube structure, and a deactivated surface-bonded sol-gel coating on a surface of the tube structure to form a stationary phase coating on that surface of the tube structure. According to the present invention the deactivated stationary phase sol-gel coating enables separation of analytes while minimizing adsorption of analytes on the separation column structure.

The invention relates to a method for simultaneously detecting multiple residual solvents in ceftriaxone sodium, which adopts a gas chromatographic analysis process to simultaneously detect six organic solvents in medicines, including methanol, ethanol, acetonitrile, acetone, ethyl acetate and triethylamine. The gas chromatographic process is adopted to simultaneously detect the contents of the six organic solvents, and has the advantages of high sensitivity, favorable repetitiveness and high precision; by using a standard addition process, the method does not need any additional standard substance as an internal standard, only needs a pure substance for predicting components, can counteract the matrix effect, and is simple to operate; by using a headspace sampling process, the method prevents the direct solution sample from interfering with detection and from polluting the chromatographic column; and a programmed heating process is adopted to effectively separate low-boiling-point organic solvents from high-boiling-point organic solvents.

The invention relates to a method for detecting alkaloid in tobacco. The method comprises steps that: step 1, a tobacco sample is added to an alkaline solution; the mixture is subject to an ultrasonic treatment; an organic solvent containing quinoline is added to the mixture, and the mixture is processed through oscillation extraction; an organic layer is condensed, such that a sample solution is obtained; step 2, the sample solution is detected by using a gas chromatograph-mass spectrometer, such that alkaloid in tobacco is processed through quantitative and qualitative determinations. The detection method provided by the invention is advantaged in simple steps, convenient operation, good reproducibility, high sensitivity, and high recovery rate. With the method provided by the invention, all the components of tobacco alkaloid can be completely extracted. Therefore, the method can be effectively used in analysis and detection of tobacco alkaloid.

The invention relates to a method for detecting eight volatile carbonyl compounds in a filter tip through liquid chromatography-tandem mass spectrometry. The eight volatile carbonyl compounds are formaldehyde, acetaldehyde, propanal, acetone, acraldehyde, crotonaldehyde, butanal and 2-butanone. The method comprises the following steps: performing ultrasonic extraction on the carbonyl compounds in a filter tip by using an acetonitrile / water mixed solution, performing 2,4-dinitrophenylhydrazine derivatization reaction, and analyzing through a liquid chromatography-tandem mass spectrometer (LC-MS / MS). Compared with the original gas chromatography, the LC-MS / MS method used in the method has the following advantages: (1) the LC-MS / MS method is higher in sensitivity, and the two-stage mass spectrometry can more effectively eliminate the false positive result, thus ensuring that the qualitative analysis accuracy is higher; (2) separation is performed through liquid chromatography, and 2,4-dinitrophenylhydrazone of the carbonyl compounds has favorable stability; (3) the sample does not need to be purified, and the pretreatment is simple and efficient; and (4) the method can realize the simultaneous detection of the eight volatile carbonyl compounds.

The invention discloses a method for determining 101 kinds of pesticide residues in tobaccos or tobacco products simultaneously. The method is characterized by comprising the following steps: adding anhydrous sodium sulfate, an inner label and acidified acetonitrile into a tobacco sample, carrying out vortex extraction, carrying out centrifugal layering, enabling a certain amount of extraction liquid to pass through a solid-phase extraction column for purification, diluting by using acetonitrile / methylbenzene mixed liquid with the volume ratio being 3 to 1, concentrating the diluting liquid, carrying out solvent exchange by using normal hexane so as to obtain a mixture, enable the mixture to pass through an organic-phase filtering membrane, and detecting by using a gas chromatograph-mass spectrometer. The method disclosed by the invention has the advantages that a pretreatment method of a tobacco sample is simplified, the sample analysis time is shorted, simultaneously clean on-machine solution is obtained, and the maintenance frequency and the use cost of instruments are reduced.

The invention discloses an automatic online monitoring method and device for VOCs (volatile organic chemicals) in water, which can be used for automatically and quickly monitoring the contents and concentration of VOCs in water, and transmitting the real-time data to a remote center platform and realizing remote reverse control. The device comprises an automatic water taking device, an automatic sampling device, a purging and gathering concentrator, a gas chromatograph, a tandem type detector, an industrial controller and a data transmission module. The method and the device disclosed by the invention are fit for automatically on-line monitoring 60 volatile organic chemicals published by the method 502.2 of US EPA (Environmental Protection Agency), particularly for 29 volatile organic chemicals stipulated in Sanitary Standard for Drinking water. The method and the device have the advantages of quick speed, high monitoring sensitivity, stable and reliable performance, full-automatic monitoring and data transmission and on the like, can be applied for automatic monitoring stations, mobile emergency monitoring stations and labs.

The invention discloses a GC-MS detection method for phosphate ester flame retardant plasticizers in textiles, comprising the following steps: 1) preparing a sample solution to be tested; 2) preparing standard solutions: dissolving the phosphate ester flame retardant plasticizers with a solvent, thus preparing gradient standard working solutions; 3) injecting the gradient standard working solutions to GC-MS, selecting an ion monitoring mode to assay, determining peak positions of the phosphate ester flame retardant plasticizers, recording peak areas of quantitative ions, making a standard curvilinear equation with concentration for x-axis and peak area for y-axis; 4) replacing the gradient standard work-solutions in the step 3) with the sample solution obtained in the step 1), determining the phosphate ester flame retardant plasticizers in the sample solution and peak areas thereof with the method in step 3), calculating with the standard curvilinear equation obtained in the step 3) so as to obtain the contents of the phosphate ester flame retardant plasticizers in the sample solution.

The solid phase capillary miniature extractor includes mainly one four-way valve and one six-way valve connected via gas path; one capillary extracting column made of elastic hollow quartz capillary, stainless steel capillary or stainless steel capillary with inside quartz lining, connected to the six-way valve and with cross-linking coated fixing phase in the inside wall; one heater outside the extracting column for heating; one miniature three-way pipe connected to the extracting column, the six-way valve and conveying gas path for the desorption sample; and one conveying pipe inserted into the gas chromatographic sample injector. The liquid sample pushed by the auxiliary carrier gas enters first to the extracting column via the four-way valve and the six-way valve; the four-way valve is then turned and the extracting column is heated; and the six-way valve is finally turned for the desorbed component to enter the gas chromatographic sample injector.

An active carbon fibrous solid phase microadsorption method used in gas-phase chromatographic is to use active carbon fiber ACF with fine adsorption to substitute organic coating solid phase extraction fiber, use natural or synthetic high polymer of asphalt or bakelite assistant with inorganic fillers to make the original fiber then to get porous active carbon fiber with strong adsorption ability and enough strength via high temperature carbonization and activation under the protection of inert or reductive gas. Said porous active carbon fiber as the inner chip of gas chromatograph GC sampler makes direct adsorption collection and GC sampling to the materials to be analysed and finish sampler and analysis after description in GC gas chamber, having got the aim of GC sampler zero solvation with better heat resistance than organic solid extraction fibers in solid micro-extraction.

The invention relates to a pulse helium ionized gas phase chromatographic instrument which comprises a gas carrying unit, a sampling unit, a gas path control unit, a circuit control unit, a separation unit and a test unit; the invention is characterized by further comprising a tail gas processing unit and a signal collection and data processing unit; the tail gas processing unit receives the waste gas discharged by the separation unit; the signal collection and data processing unit is a countercharge chromatograph workstation; the gas carrying unit is constructed by a solid state filter and a helium purifier to provide high purity carrying gas for the separation unit; the sampling unit is used for sampling and automatic sampling injection; the separation unit is comprises a switching procedure of three valves and four columns; the test unit is a pulse helium ionized tester. The stable path control and the circuit control parts of the invention can ensure the instrument to work for a long time and can show good response to all the impurities in the high purity gas, the measurement result can meet the gas standard requirement, the operation is simple and the whole process is in automatic control.

The invention provides an analytical method for determining aromatic constituents in tea. The method adopts HS-SPME (headspace-solid phase microextraction), combines GC-MS (gas chromatography-mass spectrometer) with the Kovats retention index (KI), employs a 50 / 30mu m DVB / CAR / PDMS type SPME head, optimizes HS-SPME parameters, establishes an AMDIS (automated mass spectral deconvolution and identification system) combined with the KI, and establishes a tea aroma atlas database for analysis. Compared with the conventional tea aroma analysis, the provided analytical method is better in accuracy, efficiency, flexibility and comprehensiveness, and can be effectively applied to qualitative and quantitative analysis for identification of the aromatic constituents in the tea.

There is provided a pulsed flow modulation gas chromatograph mass spectrometer with supersonic molecular beams apparatus and method for improved sample analysis. The apparatus includes a gas chromatograph with an injector for the analysis of sample compounds, a first analytical column in the gas chromatograph, a sample storage, a gas pulse generator, a pressure generator, a conduit for transferring the sample compounds into a second analytical column having a different polarity than the polarity of the first analytical column, a second gas pulse generator, a transfer line for transferring the sample compounds into a supersonic nozzle, a member for adding a makeup gas to the output gas flow of the second analytical column before the supersonic nozzle, an element for reducing the flow rate of the added makeup gas, a supersonic nozzle for the expansion of the sample with the combined second analytical column and added makeup gas, a fly-through electron ionization ion source, a mass analyzer, an ion detector for the detection of the ions of the sample compounds after their mass analysis, a data processor and presenter, and a repeater for repeating the cycle of the first gas pulse of relatively high flow rate followed by the second gas pulse of intermediate flow rate.

The invention relates to the technical field of detection and analysis instruments and in particular relates to an automatic gas chromatographic control system. The automatic gas chromatographic control system comprises an automatic gas chromatographic instrument center controller, a networking and data communication interface, an automatic chromatographic data processing and controlling workstation and a chromatographic analysis database; the automatic chromatographic data processing and controlling workstation comprises a chromatogram map processing and analyzing module. According to the automatic gas chromatographic control system, an embedded type technique, a software component technique and a networking technique are used. Compared with the prior art, the automatic gas chromatographic control system has the advantages that the integration of the gas chromatographic control system in controlling, processing and analyzing process can be achieved, so that the integration of embedded type control, operation management, data acquisition, chromatographic processing and analysis and report form statistics of the gas chromatographic instrument is improved; the networking control and sharing of a chromatographic analyzer are achieved; the componentization and configuration of the controlling, processing and analyzing software of the chromatographic instrument are achieved, so that the novel function can be quickly expanded by the software of the chromatographic instrument in a building block manner according to the requirement change of users.

The invention discloses a method for synchronously analyzing a base, a nucleotide, an organic acid, a fatty acid, an amino acid and a saccharide metabolic product with a two-step derivation method. The method comprises the following steps of: performing a series of physicochemical method technical treatment such as ultrasonic treatment, centrifugation, oximation, urea removing, phosphorus removing, sulfur removing, protein removing, nitrogen blowing, vacuum drying, and trimethyl silylation derivation on biological substrate samples (such as urea, blood, cerebrospinal fluid, and tissue fluid); and detecting the biological substrate samples by adopting a gas chromatograph-mass spectrum combination technology. Due to the adoption of method, programmed treatment can be performed on the biological substrate samples simultaneously, and over 400 kinds of metabolic intermediate and final products of over five kinds of substances can be detected at one time.

The invention discloses a gas hydrate sampling and analyzing device and a method. The device comprises a hydrate generation kettle, a sampling module, a drive control module, a sample decomposition module, a weighing analysis module and a vacuumizing module, wherein a stirrer is arranged in the hydrate generation kettle; a gas inlet pipe and a liquid inlet pipe are connected to the top part of the hydrate generation kettle; the sampling module is formed by a transparent high pressure resistant resin glass tube, an upper compression piston, a lower compression piston, an upper hydraulic linkage shaft, a lower hydraulic linkage shaft and a sample delivery pipe; the weighing analysis module comprises an electronic analytical balance, a gas chromatograph and relevant connecting pipelines and components; the drive control module comprises a compression piston, a drive linkage shaft, a hydraulic driver, a spiral elevator, a control computer and the like; and the vaccumizing module is formedby a vacuum pump and relevant connecting pipelines and components. Any height space in a reaction kettle can be sampled with any volume, and any phase state of gas phase, solution phase, hydrate slurry phase and hydrate phase in a hydrate reaction system can be sampled and analyzed.

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 relates to a method for preparing an herbicide, and provides a method for preparing a natural herbicide, which has the advantages of mild reaction conditions, simple process, low cost and easy industrialized mass production. The method comprises the following steps of: dissolving alpha-terpineol insolvent, and adding alkali, metallic oxides and peroxides; stopping the reaction when the gas chromatographic analysis shows that the content of the alpha-terpineol is less than 0.5 percent; filtering and recovering the metallic oxides; distilling filtrate distillation to recover solvent, obtaining 1,2-epoxide; dissolving the 1,2-epoxide in the solvent, and adding acid; stopping the reaction when the gas chromatographic analysis shows that the content of the 1,2-epoxide is less than 2 percent; distilling reaction solution to recover solvent, obtaining an isomerized product of the 1,2-epoxide; dissolving the isomerized product of the 1,2-epoxide in the reaction solvent, adding alkali for stirring, and adding 2-methyl benzylchloride; stopping the reaction when the gas chromatographic analysis shows that the content of the isomerized product is less than 2 percent; pouring the reaction solution in water, adjusting the pH value of the mixed solution to neutral, and separating out organic phases; and obtaining the finished product by the water phase extraction, the combination of the organic phases, and distillation and recovery of the solvent.

The invention relates to a culture-free biochemical method for analyzing the microbial community structure of yeast for traditional brewage, in particular to a method for analyzing the microbial community structure of yeast for traditional brewage by using the phospholipid fatty acid spectrogram analysis technique. The method comprises the following steps: (1) weighting a certain amount of yeast sample which is pulverized and evenly mixed; (2) adding a buffer solution and an organic reagent to obtain an organic phase containing lipids; (3) separating the organic phase by small silica gel columns, eluting and collecting organic components containing polar lipids; (4) carrying out methyl esterification under mild condition, and adding an extracting reagent to obtain corresponding fatty acid methyl ester; (5) carrying out quantitative analysis on the fatty acid methyl ester by using a gas chromatogram-mass spectrogram combined instrument; and (6) determining the characteristics of the microbial community structure in the sample according to characteristics of different phospholipid fatty acid compositions. The invention provides an accurate and quick culture-free detection means for researching the composition of the microbial community structure of yeast for brewage and knowing the law of growth and decline of different microbial communities in the yeast preparation process.

The invention provides a blowing and sweeping trapping instrument used for continuously observing volatile organic compounds in water online, and relates to detection on the volatile organic compounds in a water body. Nitrogen has access to a sample outlet of a sample injection six-way valve through a nitrogen inlet connected with the sample injection six-way valve and a quantitative loop, a sample outlet of the sample injection six-way valve is connected into a blowing and sweeping chamber. Gas stripping is conducted on samples in the blowing and sweeping chamber. Gas blown and swept out of the blowing and sweeping chamber enters a trapping pipe sequentially through a hand-operated six-way valve, a drying pipe and a ten-way valve. A circulation water cooling system is arranged outside the trapping pipe, a refrigeration piece and a heating pipe. The water inlet of a drain valve is formed in the blowing and sweeping chamber. The inlet of a drying pipe flow controller is externally connected with a dry air source, and the outlet of the drying pipe flow controller is connected with the drying pipe. The target object outlet of the ten-way valve enters a separation detector through a heating analysis flow controller and a gas phase color spectrum sample injection six-way valve. The nitrogen inlet of the gas phase color spectrum sample injection six-way valve is externally connected with a nitrogen source. The dry air inlet of the separation detector is externally connected with the dry air source. The hydrogen inlet of the separation detector is externally connected with a hydrogen source.

A micro counter-current flame detector is provided that is both sensitive for photometric and ionization detection for gas chromatography (GC). In the detector, a stainless steel capillary (0.01″ i.d.) supplying oxygen functions as a burner, which supports a compact flame that burns in a counter-flowing excess of hydrogen. In the “micro Flame Photometric Detector” (μFPD) response mode, the background emission level is reduced by over an order of magnitude compared to previous experiments using a fused silica capillary burner, resulting in greatly improved detection limits. The device can successfully operate as both a selective and universal GC detector. Results indicate that this micro counter-current flame method yields comparable performance to conventional Flame Photometric and Flame Ionization Detectors.

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 discloses a device and a method for observing trace volatile organic compounds in atmosphere in an online manner, and relates to detection of volatile organic compounds in atmosphere. The device is provided with a six-way valve, a drying pipe, a mass flow controller, an air pump, a refrigerating sheet, a heating sleeve, a collecting trap, a circulating water radiating system, screen cloth, a drying pipe flow control valve, a flow control valve and a gas-phase chromatography sample injection six-way valve. Air samples can be fed into the collecting trap via the screen cloth, the air pump, the mass flow controller, the drying pipe and the six-way valve sequentially, the heating sleeve sleeves the collecting trap, the radiating sheet is arranged on the outer periphery of the heating sleeve, an inlet of the drying pipe flow control valve is externally connected with an N2 source, an outlet of the drying pipe flow control valve is connected with an inlet of the drying pipe, an inlet of the flow control valve is connected with an outlet of the gas-phase chromatography sample injection six-way valve and the N2 source, an outlet of the flow control valve is connected with the six-way valve, the gas-phase chromatography sample injection six-way valve is externally connected with a gas-phase chromatography pulse flame photometric detector, and the gas-phase chromatography pulse flame photometric detector is externally connected with an H2 source and a purified air source.