5163 results about "Chromatography gas" patented technology

A technique for detecting the presence of microorganisms in a simple, rapid, and efficient manner is provided. More specifically, the technique involves identifying one or more volatile compounds associated with a particular microorganism of interest. The volatile compounds may be identified, for instance, using solid phase microextraction in conjunction with gas chromatography / mass spectroscopy (“GC / MS”) analysis methods. Once identified, an indicator may then be selected that is configured to undergo a detectable color change in the presence of the identified volatile compound(s). If desired, the indicator may be provided on a substrate to form an indicator strip for use in a wide variety of applications. In this manner, the presence of the microorganism may be rapidly detected by simply observing a color change of the indicator strip.

Gas chromatographs of the invention generally comprise four or more analysis channels. Specifically, four or more gas chromatography columns are configured for parallel analysis of four or more gaseous samples with detection being effected using a microdetector array comprising four or more microdetectors. In one embodiment, the four or more microdetectors 510 are microfabricated detectors, and are integrally formed with a substrate or with one or more microchip bodies mounted on a substrate. In a preferred embodiment, a microdetector array comprises four or more thermal conductivity detectors having one or more thin-film detection filaments. A preferred heated environment for highly parallel gas chromatographs is also disclosed.

Disclosed are a method of detecting a leak of fluoroolefin compositions and sensors used therefor. In particular, the method is particularly useful for detecting a leak of a fluoroolefin refrigerant composition from a cooling system of an automotive vehicle. Such fluoroolefin refrigerant compositions have double bond structures which make them particularly well suited with sensing technologies, including: infrared sensors, UV sensors, NIR sensors, ion mobility or plasma chromatographs, gas chromatography, refractometry, mass spectroscopy, high temperature thick film sensors, thin film field effect sensors, pellistor sensors, Taguchi sensors and quartz microbalance sensors.

Gas chromatographs of the invention generally comprise four or more analysis channels. Specifically, four or more gas chromatography columns are configured for parallel analysis of four or more gaseous samples with detection being effected using a microdetector array comprising four or more microdetectors. In one embodiment, the four or more microdetectors 510 are microfabricated detectors, and are integrally formed with a substrate or with one or more microchip bodies mounted on a substrate. In a preferred embodiment, a microdetector array comprises four or more thermal conductivity detectors having one or more thin-film detection filaments. A preferred heated environment for highly parallel gas chromatographs is also disclosed.

A method is described for recovering a noble gas, such as xenon or krypton, from a first gas mixture comprising a plurality of components, one of which is the noble gas and the others are typically helium and / or nitrogen, argon, and relatively light fluorocarbons. The gas mixture is first conveyed to a gas chromatography column for separating the noble gas from the other components of the gas mixture. As the noble gas travels relatively slowly through the column, the other components are exhaust from the column before the relatively slow noble gas. Following the exhaust of these other components, a purge gas is supplied to the column to flush the noble gas therefrom. A second gas mixture comprising the noble gas and the purge gas is conveyed from the column to a membrane separator to separate the second gas mixture into a noble gas-rich gas stream and a purge gas-rich gas stream, which may be recirculated back to the column for re-use.

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.

A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

The invention discloses a method used for measuring the content of gasoline olefin on the basis of Raman spectra, sequentially comprising the steps as follows: the content of olefin in a training sample is measured by a fluorescent indicator adsorption method or a multidimensional gas chromatography; the Raman spectra of the training sample is measured; the measured Raman spectra is preprocessed by smooth filtration, benchmark line correction and standard normalization; a gasoline olefin content correction model is established by applying a least squares support vector machine on the Raman spectra of the preprocessed training sample and the measured olefin content; the Raman spectra of the oil sample to be measured is measured and the Raman spectra is preprocessed by smooth filtration, benchmark line correction and standard normalization; and the olefin content of the oil sample to be measured is calculated according to the correction model. The method combines the Raman spectra with the least squares support vector machine to analyze the content of the olefin in the gasoline, obviously improves the detection precision, greatly shortens the measurement time simultaneously, has no consumption of the sample during the measurement process, and has important significance on the quality control during the oil processing.

A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

The present invention relates to a method and accompanying device for separating a known or unknown sample into one or more subsamples. By comparing the subsample's measurement profile data to the sample measurement profile data, the performance of the separation can be determined. The separation could be chromatography [such as high-performance liquid chromatography (HPLC), gas chromatography (GC), or the like], electrophoresis [such as capillary electrophoresis (CE) or the like], or another separation technique. The measurement profile data could be ultraviolet / visible (UV / Vis) spectra, mass spectra (MS), or another measurement technique.

Devices for enhancing the sensitivity of a microsensor or any other micro device by providing on-line preconcentration. Microconcentrators that can be integrated with a sensor or a micromachined GC to enhance the signal to noise ratio can include a miniaturized sorbent trap fabricated on a microchip. The microconcentrator can be made on a silicon substrate so that a sensor can be integrated on the same chip. The microconcentrator is composed of at least one microchannel lined with a microheater for in-situ heating. Preconcentration may be achieved on a thin-film polymeric layer deposited above the heater in the microchannel. Rapid heating by the channel heater generates a “desorption pulse” to be injected into a detector or a sensor.

A mass spectrometer has an atmospheric pressure chemical ionization source that includes a first ionization portion including a needle electrode, for generating a primary ion by discharge of the needle electrode a primary ion introduction aperture, and a second ionization portion including an introduction aperture, for generating a sample ion by the reaction between the primary ion and the sample gas introduced from an end of a column of gas chromatography, a sample ion movement aperture; and a mass analysis portion; wherein the end is arranged at a position satisfying the relation r≦2R where R is a radius of an inner diameter of the aperture and r is a distance between an axis connecting the center of the aperture and the center of the aperture, and the end.

The invention provides a gas / liquid tandem mass spectrum system with a multimode ionization ion source. The gas / liquid tandem mass spectrum system is characterized by being formed by connecting a multimode ionization ion source, a gas chromatography, a Liquid Chromatography, a mass analyzer with purification and enrichment functions, and a flight time mass spectrometry in series. According to the invention, the applicability of a single-ion-source mass spectrometry specific to analysis of polymorphic samples is broadened, meanwhile, the high resolution performance of fragment ions on mass selection and analysis is enhanced, and the researches on an ionic reaction mechanism are realized.

A two-dimensional gas chromatograph with a primary column (14) and dual secondary columns (26, 28) is described. Flow rates in the primary column are less than those in the secondary columns due to an accumulation valve (16). Typically the ratio of second and third column flow capacities combined to primary column flow capacities between about 10 to 1 and 30 to 1. Volatile organic compounds are detected in environmental samples of air water, soil and in body fluids of animals and humans.

The invention provides a building method for a rhubarb medicinal material trueness / falseness and species prediction model. According to the model, category identification of quality rhubarb, fake rhubarb and three rhubarb species is realized on the basis of a gas chromatography-mass spectrum technology in combination with partial least square discriminant analysis. The building method comprises the following steps: (1) collecting samples; (2) preparing the samples; (3) acquiring GC-MS data; (4) performing data processing and multivariate analysis, wherein cluster analysis and principal component analysis are performed by comparing the differences of chromatographic behaviors of rhubarb of different sources; (5) building the prediction model; and (6) verifying the model. Two built category prediction models are proved to have 100 percent identification accuracy and prediction accuracy. Through adoption of the method, trueness / falseness and species identification of rhubarb are realized by modeling, so that a reliable conclusion and high integrity are achieved; the defects of an existing method are overcome; and a more feasible and reliable new thought is provided for the trueness / falseness and species identification of rhubarb medicinal materials and decoction pieces.

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.

The invention provides improved apparatus for, and methods of, ionizing analyte molecules in a flow of gas, typically at or around atmospheric pressure. The invention may be used to facilitate mass spectrometric analysis of analytes comprised in the effluent form a gas chromatograph. Ionization may be effected by atmospheric pressure chemical ionization or by atmospheric pressure photo ionization.

The invention discloses zhuangfei strawberry essence and a preparation method thereof; the strawberry essence usually comprises faint aroma, sweet aroma, acid aroma, fruit aroma, flower aroma, and characteristic aroma, and the mass fractions of the components are 6-8 parts of faint aroma, 12-15 parts of sweet aroma, 15-25 parts of acid aroma, 40-45 parts of fruit aroma, 3-5 parts of flower aroma,and 5-8 parts of characteristic aroma. The method comprises the following steps: removing pedicles of fresh zhuangfei strawberries, washing, refrigerating and cooling the strawberries, triturating the strawberries by a triturator to obtain pasty strawberries; detecting the aroma components in ripe zhuangfei strawberry fruit by a solid-phase microextraction-gas chromatography / mass spectrum-automatic mass spectrum deconvolution identification system, and determining an optimal formula composition with reference to quantitative data of GC-MS. The zhuangfei strawberry essence obtained by the invention has good natural sense and native sense, and has better application effect in dairy and cold drink than other strawberry essence.

The invention discloses a measurement method of a volatile organic compound in tobacco lining paper with high determination accuracy and good repeatability, which is suitable for simultaneously determining dozens of volatile organic compounds. The measurement method is as follows: taking fluorobenzene as an internal standard substance; using headspace gas chromatography for measuring the content of the volatile organic compound in the tobacco lining paper; wherein a detector in the headspace gas chromatography is a mass spectrometry detector. The measurement method takes the fluorobenzene as the internal standard substance, uses the headspace gas chromatography / mass spectrometry for measuring the content of the volatile organic compound in the tobacco lining paper, and has the following advantages that the fluorobenzene has stable chemical property and are very similar to determinand in every performance, and the peak time appears in the middle of 19 target VOCs to be detected; therefore, the fluorobenzene is the very suitable internal standard substance, can eliminate the influence of ground substance in the tobacco lining paper on the measurement, causes materials which can not or are difficult to peak to be measured, and has high measurement accuracy and few interference factors.

The invention relates to a detection method for the perfuming uniformity of cigarette shreds. The method sequentially comprises the following steps: A. confirming a label of characterization uniformity; B. sampling from an exit of a cigarette shred perfuming roller; C. balancing the cigarette shred sample obtained by sampling; D. pre-treating the cigarette shred sample by extraction with a rapid solvent extraction instrument, and preparing a filtering medium; E. carrying out gas chromatography and mass spectrum combined analysis on the filtering medium, taking the label as the analysis object, and adopting a selected ion scanning pattern; and F. calculating the content of the label in the cigarette shred sample, obtaining a standard deviation (SD), and reflecting the perfuming uniformity degree of the cigarette shred by the SD value. The detection method adopts the gas chromatography / mass spectrum instrument as the separation and analysis means, and quantifying-researches the uniformity of the perfuming procedure of the cigarette shreds, thereby confirming the uniformity of cigarette shred perfuming. The detection method is applied to the perfuming technological process in the cigarette production, thereby providing a practical and scientific method for the detection of the cigarette perfuming precision.

A mass spectrometer has an atmospheric pressure chemical ionization source that includes a first ionization portion including a needle electrode, for generating a primary ion by discharge of the needle electrode a primary ion introduction aperture, and a second ionization portion including an introduction aperture, for generating a sample ion by the reaction between the primary ion and the sample gas introduced from an end of a column of gas chromatography, a sample ion movement aperture; and a mass analysis portion; wherein the end is arranged at a position satisfying the relation r≦2R where R is a radius of an inner diameter of the aperture and r is a distance between an axis connecting the center of the aperture and the center of the aperture, and the end.

A method for the rapid analysis of the fatty acid components present in a fat and / or oil-containing material is provided wherein the levels and types of fatty acids present in a sample are determined using Fourier Transform Near Infrared (FT-NIR) spectroscopy. The FT-NIR technique is developed by preparing a calibration matrix based on FT-NIR and Gas Chromatography (GC) analysis of known standards, and subsequently using the calibration matrix to analyze the FT-NIR spectral data obtained from a sample to be tested.

The invention discloses a porous polymer nanoparticle and a preparation method thereof. The method is characterized by adding 10-200 parts of polymers, 0-200 parts of additives and 300-1000 parts of solvents by weight into a dissolution kettle with a stirrer and a thermometer, stirring to dissolve the mixture at 30-100 DEG C and obtaining polymer solution through defoaming and aging; and placing the polymer solution into an electrostatic field under 5-25kV to prepare the porous nanoparticle through electrostatic spraying. Smooth split of the nanoparticle is realized by a frozen breaking method, thus achieving the aims of minute observation, research and control of the inside structure of the nanoparticle. Electron microscope scanning test result shows that the diameter of the nanoparticle is distributed from hundreds of nanometers to thousands of nanometers, and the nanoparticle matrices are all of porous structure. The porous nanoparticles in the shapes of balls, red blood cells and round lanterns can be prepared by changing the technological conditions. The nanoparticle has the advantages of small diameter, large specific surface area and controllable surface and inside structure and is used in such fields as drug release, catalyst carriers, chemical sensors, biomolecule analysis, gas chromatography, ion exchange and polymerization carriers.

Provided is an electrophotographic photosensitive member in which an undercoat layer is a layer of which at least one selected from the group consisting of a compound represented by the formula (1), a compound represented by the formula (2), a compound represented by the formula (3) and a compound represented by the formula (4) can be detected by gas chromatography analysis when the undercoat layer is heated at 150° C. for 60 minutes by headspace method.

An analyte pre-concentrator for gas chromatography is disclosed generally comprising a tube having a restricted outlet and packed with an adsorbent, wherein the tube serves as the liner of a chromatographic injector, as an adsorbent trap coupled to a chromatographic column, and / or as an adsorbent trap coupled to a headspace sampler. Preferably, a heating device allows the tube to be heated. In a preferred embodiment, the analyte pre-concentrator further comprises a column isolating accessory so that a chromatographic column can be temporarily isolated from substances flowing through the tube.

The invention provides a method for detecting volatile organic compound in a cigarette filter, which comprises the following steps: a) preparing a sample; b) preparing a matrix correcting agent; c) preparing an interior label solution; d) preparing a standard sample; e) preparing a standard working solution; f) performing detection by using headspace-gas chromatography / mass-spectrography; and g) calculating a detection result of the volatile organic compound in the sample. The invention establishes the method for detecting the volatile organic compound residue in the cigarette filter for the first time. By using the saturation sodium chloride aqueous solution as the matrix correcting agent and the fluorobenzene as the interior label, the matrix effect of a solid absorption matrix (namely the cigarette filter) is efficiently reduced and the error caused by the poor repeatability of the pre-treatment and the low precision of instrument is reduced. In the whole process, no organic solvent is used. The method has the advantages of environmental friendliness, energy-saving and low consumption. The detecting method has few interference factors and good repeatability, is accurate in measuring result, is simple to operate, and can be used for obviously increasing the sensitivity of headspace analysis.

The invention provides a method for quickly detecting content of fatty acid in marine microalgae, which extracts and saponifies fat in the microalgae by saturated KOH-CH3O, integrates the extraction process and the saponification process into one step, performs methyl esterification by HCl-CH3OH to obtain the fatty acid, performs gas chromatographic mass spectrometric analysis on the fatty acid after extraction, saponification and the methyl esterification, and comprises the following steps: (1) sample preparation, (2) extraction, saponification and methyl esterification of the fatty acid, and(3) gas chromatography detecting condition for the fatty acid. The method has the advantages of simple operation steps, time conservation, simple and quick method, visual data, and increase of the comparability between samples.

A self-contained micro-scale gas chromatography system that includes a plurality of gas chromatography components arranged on a micro-fluidic platform with nearly zero dead volume “tubeless” fluidic connections for the gas chromatography components. The micro-fluidic platform includes a plurality of flow channels that provide fluid flow paths for a sample, carrier gas and waste gas through and among the micro-fluidic platform and the plurality of gas chromatography components. The system may also include an on-board supply of carrier gas and on-board waste management, as well as a thermal management scheme making the system suitable for use in oil and gas wells and also other remote environments.

The invention relates to a mine gas beam tube monitoring system, comprising an automatic sampling device which consists of a gas path switching electromagnetic valve and a suction pump. The gas path switching electromagnetic valve is connected with a partial channel through a sampler and a single-core beam tube of a moisture separator and then a conduit head through a partial beam tube cable and is controlled by a programmable controller after a main beam tube cable is connected with a moisture separator box. The system is characterized in that the monitoring system also comprises an automatic sampling device which is composed of a sample making device. The sample making device consists of a non-oil injection pump and a conversion electromagnetic valve controlled by the programmable controller, a shunting needle-shaped valve with an emptying end, a dryer, a filtering device, a quantitative tube and a single-core beam tube of a flow meter which are successively connected through an automatically sampling pipe. The automatic sampling device is connected with a gas chromatography detection device for analyzing and outputting data to a computer. The computer controls the programmable controller and outputs detection results. The dryer and the filtering device are provided with long service life. The measuring point number extension is convenient and can be maintained easily. The cost is low. The sampling device samples steadily. The precision of detected gas is high. A recognition method for the gas explosiveness and the fire hazard is disclosed. The decision according to the analysis result is clear and prompt.