5126 results about "Chromatography gas" patented technology

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.

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 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.

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 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 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.

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.

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.