FIELD: physics, measurement.
SUBSTANCE: invention is related to chromatograph intended for analysis of gaseous substance. Device comprises supplying system for sample supply, open tubular capillary column for separation of sample components, device for temperature control for adjustment of column temperature, detector for detection of separated sample components. Specified column comprises bundle of open tubular capillaries. Besides specified capillaries have gas permeable walls that comprise polymer membrane.
EFFECT: improved chemical specificity of detector, improved strength of structure.
22 cl, 3 dwg
The technical field to which the invention relates.
The present invention relates to a chromatograph designed for analyzing a gaseous sample. The chromatograph has a feed system for feeding the sample, an open tubular capillary column for separating components of a sample, the device temperature control for regulating the temperature of the column and a detector for detecting the separated components of the sample, and the specified column contains a bunch of open tubular capillaries.
The level of technology
The chemical state of the samples in the form of a gas phase is formed vaporized or gaseous chemicals mixed in the environment, usually in the air. This environment may also process gases or vacuum. For the detection and identification of specific chemical substances in a particular environment, using a detector.
The main characteristic of the chemical detector is its ability to convert the chemical state into an electrical signal and transmit this signal for further processing. In a typical case, the purpose of the detector is to conduct both qualitative and quantitative determination of specific chemical substances in certain environments. In this case there is technical the roblem, related to the fact that the output signal of the detector is not absolutely specific, i.e. has sensitivity to other chemicals, which are not the subject of research. The specified property is often termed "cross-sensitivity", and it usually leads to a false identification of a target substance.
There are two main directions of solving the problem of cross-sensitivity chemical detection: (i) development of more specific sensors (under the sensor means, the first part of the measuring chain that converts the input variable parameter suitable for measuring signal) or (ii) conducting chemical separation prior to detection. In the second case, as a rule, apply chromatographic techniques, filtering, adjustable methods of adsorption-desorption, as well as special procedures preparation of the sample, including dissolution, phase separation, extraction, chemical deriving compounds, and ion exchange. In the embodiment, the detecting chemical condition, with view of the gas phase (especially in the allocation of small components in ambient air portable detector), the stages of preparation of the sample are complicated, because they are difficult to automate, to make it more mobile and less time consuming. So about what atom, for fast real-time monitoring, they are not suitable.
Of the other listed possible approaches to conducting chemical separation of well-known methods of analytical chemistry chromatography. Gas chromatography (GC) is a preferred method of separation of stable and volatile compounds, as well as samples that are in the gas phase. Within this method perform chemical separation by fractionation of the mixture components on the mobile gas phase and a stationary solid or liquid phase held on a solid substrate. In stationary chromatographic system retention time of the analyte by the adsorbent (i.e., the time of passage of the sample from the entrance through the column to the detector) analyzed for specific compounds is constant, i.e. this parameter can be used to identify such compounds. Thus, although chromatography, first and foremost, is a separation technology, it can help to identify the separated compounds of complex sample values of their retention time. The process is carried out in GC instrument, usually consisting of feeding system sample, the carrier gas and block (blocks) regulate the flow of the specified gas, one or more columns inside the chamber (ka is the rule, equipped with a thermostat) and one or more chemical detectors.
From the point of view of separating power and, thus, the resolution achieved in the analysis, the key technical component of the GC column is. Columns can be divided into two main types: (i) Packed (printed) column and (ii) hollow (open) tube, or the so-called capillary column. Packed column design of pipes, made, for example, stainless steel, Nickel, or glass, and its inner diameter is typically in the range of 1-10 mm Column filled with inert retaining powder. This is usually hard-shelled land with an average internal pore diameter of 1-10 μm and a particle size of 100-200 μm. Column of the second type, i.e. an open tubular capillary column has a small inner diameter of 10-1000 μm. It is usually design of fused silica (glass of very high purity), and the outer wall protects hard and dense polymer type polyimide. As a rule, speakers have a tubular shape with no restricted passage for the flow in the middle part of the column. The inner surface of fused silica chemical way modify the coatings or films of various types, providing the formation of the so-called stationary phase. These phases have different polarity and, thus, elective in relation to the separation process. The stationary phase may be a liquid layer or a thin film, typically made of a polymer such as polysiloxane, silicone or polyamide, and depending on the situation, these layer and film function in different ways. For the total separation capacity of the column is influenced by such parameters of the film stationary phase, such as chemical composition, microstructure, morphology, and thickness.
Of all the types of columns in analytical chemistry preferred is an open tubular capillary due to its high separation capacity relative to the total time of analysis, improved long-term stability and a higher quality of analysis (the latter property is determined by the high reproducibility of the manufacturing process).
At the current level of technology the use of tubes with open tubular GC capillaries in combination with various portable chemical detectors are well known. Confirmation of this can be, in particular, U.S. patent No. 5114439 and 5856616, which describes the use of compact size GC columns with low power consumption, designed for portable applications. In addition, in patent document WO 9941601 describes using a combination of GC columns with low energy consumption and specific system is neither sampling. Further, U.S. patent No. 4888295 and 6354160 describe respectively the application is acceptable from a commercial point of view" GC column in combination with a detector formed by a matrix of electrochemical sensors, and GC column used in conjunction with detectors based on surface acoustic waves, and the function of open tubular columns can perform column formed on silicon wafers (see also U.S. patent No. 6134944).
To apply GC method in a portable, preferably hand (i.e. hand-held)devices requires that they consume little energy, were light and compact in size, and also ensured the rapid detection, while at the same time high resolution because of good separation ability. To date, the improvement of operating parameters of portable devices was mainly due to the use of high temperatures in the columns, as well as improvements in temperature control and design of the heating system. In addition, improvements included modifications of the flow of carrier gas and construction of special systems of sampling and detection.
Other ways of improving the suitability of GC method for portable applications included the use of shorter columns and columns with a reduced inner diameter with the spruce increase the efficiency and speed of analysis. However, these improvements will lead to a decrease in the separation of substances or, in the alternative situation, reduce the sample volume and will significantly increase energy consumption. In the result due to the increased pressure drop in the column will increase the cost and size of the pump. The lack of application of the sample with a small volume is that it typically reduces the detector response and increased sensitivity to local changes in the sample. Thus degrade the accuracy of retention time. In addition, the control of small volumes of fluid may be difficult from a technical point of view and expensive.
These drawbacks were overcome through the use of a column containing a bunch of open tubular capillaries (see, for example, J.I. Baumbach et al. Int. J. Env. Anal. Chem. (1997), 66, pp.225-239; Int. J. for Ion Mobility Spectrometry (2000), 3, pp.28-37).
These speakers are manufactured and sold by a limited number of companies, namely companies Alltech Associates Inc. (USA), ChemSpace s.r.o. (Czech Republic), Sibertech (Novosibirsk, Russia). Advantages multicapillary columns are to ensure short retention time and, thus, fast times of detection at a sufficiently high resolution and good separation ability. In addition, these speakers maintain high efficiency over a wide interval / min net is her flow of carrier gas. As a result, compared with conventional monocapillary speakers, they can work with high volumes of samples, and these volumes are easily injections and detected.
Thus, these properties multicapillary columns make them ideally suited for handheld portable gas chromatograph.
However, since the columns of this type are generally formed from hundreds of single capillary columns, massive beams, it is difficult to obtain a homogeneous distribution of temperature with low energy consumption, and this reduces the accuracy of the GC analysis.
Despite the fact that, compared with open tubular GC column containing a single channel, multicapillary column allow you to use a much higher flow rate (flow rate) of the sample (or the flow rate of the carrier gas) through the column, the allowable gas flow rate for normal multicapillary speakers still below 300 ml/min For some types of detector this level of consumption may not be sufficient. Such detectors include, for example, a portable Multisensor ion mobility spectrometer, designed for the detection of gaseous chemical substances in ambient air, and using the principle of end-to-end flow flow (see patent document WO 9416320 and publication Utriainen . et al. Sens. Actuators (2003), 93, pp.17-24).
The detector is implemented by a special type of ion mobility spectrometer ion mobility spectrometer, IMS). This type can be described as IMS spectrometer aspiration condenser type, or type open loop, combined with other sensors, such as semiconductor gas sensors, and temperature sensors and humidity. Laptop and portable devices chemical detection detector is manufactured under the trade names ChemPro100, M90-D1-C (Environics Oy, Finland) and MultilMS (Drager Safety, Germany). To further characterize the detector as follows: it uses a continuous stream at a flow rate, usually 800-3500 ml/min, preferably 1000-2000 ml/min, and thus provides a good statistical validity of sampling, as well as high performance and rapid return to the initial position. All of these options are essential, and in particular in the case when the task is to provide reliable early warning of the presence in the air of toxic substances. A characteristic feature of the said detector is also such a dependence of the sensitivity of flow velocity at which a higher speed is preferred. Other typical OS is the characteristics of the detector is sensitive to rapid changes in the flow (and pressure), and also to rapid and large changes in humidity and temperature.
Disclosure of inventions
There is a need for further improvements of the devices considered type. This need is met by the present invention as follows: in multicapillary column used according to the invention, the open tubular capillaries have a gas-permeable wall containing polymer membrane. In relation to the gas carrying the sample, this wall is selectively retains some of its components, skipping the others. Thus, in addition improved separation capacity of the column. In the column can be shortened to reduce the pressure required for pumping gas.
To improve the chemical specificity of the detector in the present invention according to a preferred variant implementation for chemical separation in a portable chemical detector uses a beam of hollow fiber membrane of capillaries that perform the function multicapillary GC column. Portable chemical detector is preferably a component of the handheld analyzer. Bundles of hollow fiber membranes were actively used so far in industrial processes separation of gases, industrial gas drying units, gas generators, operating the x at the place of operation, as well as in dialysis filters designed to separate components in the liquid phase. A wide range of applications of hollow fiber membranes leads to their production, which leads to low cost components in such fields of application as chemical detection using the invention.
Compared to conventional GC capillary columns, which are used in quartz, fully polymeric structure of membrane capillaries provides reduced processing costs and materials. It also contributes to ensuring economic efficiency.
The membrane wall of the hollow fiber capillaries in a specific way permeable, at least for gases having a low molecular weight, while conventional GC column based on fused quartz, this condition does not respond. In addition, the materials used in this case for the manufacture of hollow fibers, refer to the specific polymers in the sense that they, in addition to its other properties, in a special way meet the requirements of low-temperature processes of extrusion of the filaments of synthetic fibers. Examples of such materials are the polyolefins, polyamide and complex polyester, as well as materials that are less characteristic for the stretching of the fibers, in particular polysulfone and acetylcellulose. In addition, for polyhalogen capillary membranes suitable so-called bicomponent fiber, in which a given structure is formed of two polymer materials. As a typical example of such a structure can be specified on the layered capillary, in which the inner and outer walls are made of different polymers in a single process or through a separate technological operations. According to one embodiments of the invention the inner and outer walls are respectively the membrane and porous polymers, and the second of them is the basis of the carrier for the first. Thus formed, the wall has the property of selective transmission.
The bundle of hollow fibers is usually elastic, so the build process is straightforward. Because usually, the fiber bundles are used as membranes, the outer side of the fiber involved in the separation process, therefore, as a rule, do not cover any additional material. It helps to have the fluid flow on both sides. To obtain a homogeneous temperature distribution this arrangement has the advantage because it allows for temperature control beams to use fluids. The ability to make simple and consume little power temperature control allows you to reduce thermal impact on the detector, as well as to improve the accuracy of chemical identifying the paths.
Another advantage of the invention lies in the fact that the application of the bundle of hollow fiber membranes, originally developed for industrial drying apparatus, it is possible to provide for simultaneous sample and selective removal of water and other uninteresting from the analytical point of view, substances with small molecules. In General, moisture is considered the agent, acting on chemical detection, and it is desirable to specifically take into account in case of a flow detectors operating with significant flows, and spectrometers mobility of the ions. Similarly for chemical separation based filtering simultaneously with chromatographic separation of utility and other types of bundles of hollow fiber capillary membranes, selective with respect to the flue gases. Thus, as mentioned above, in the General case, the filtering can be considered as an alternative approach to improve the chemical separation ability of chemical detectors.
The size and number of capillaries that form the column containing the beam and used according to the invention can be varied within wide limits. Usually the beam is from 10 to 10000 open tubular membrane of capillaries. Each of them usually has a length of 10-100 cm and inside the diameter of 10-1000 μm. Preferably, the beam contained 100-4000 capillaries. Preferably the internal diameter of the tubular capillaries lies in the range of 50-1000 μm.
In the General case, the beam is composed of the open tubular capillaries essentially straight and parallel to each other with space between the capillaries. Undesirable small molecules such as water, migrate out of the capillaries into the free space and further to the exhaust system. When designing the column and/or beam used in the invention, the capillaries are usually held together by a holder or cap so that before the detector reached only gas from the interior volume of the capillary. The beam can be placed in the shell or casing.
In a gas chromatograph according to the invention the control device temperature preferably contains a heating environment to flow through the free space between the capillaries. This design is reminiscent of the heat exchanger and perfectly solves the problem of the heat transfer characteristic is usually for a small portable gas chromatographs. Problems such heating is considered, for example, in U.S. patent No. 5114439.
Preferably, the specified device temperature control also contained the above-mentioned casing made of insulating material. To what wow has input and output apertures, allowing the heating medium to flow through the free space between the capillaries. When using a heating medium flows along the capillary, the temperature controller further comprises a thermostatic heater regulating the temperature of the heating medium, and in a preferred embodiment, the pump and hose (tube). The pump drives the heating medium between the heater and the beam and then through the free space between the capillaries with a preferred return of this environment to the heater.
Supply system in a gas chromatograph according to the invention typically contains an absorbent filter designed for the formation of the clean air act standard sample (reference sample) for the chromatographic system. In addition, this system has an inlet for entry of the gaseous sample into the column. You can install the valve that directs the sample into the column, either directly or through the specified filter, and another valve for supplying the sample also an alternative way: through the column or directly to the detector.
In the proposed gas chromatograph detector usually contains an ion mobility spectrometer (IMS spectrometer). Preferred IMS spectrometer in the form of a combined multi-touch device, the pre is assigned for direct end-to-end flow model.
In a typical use case chromatograph according to the invention the sample is served in a column with a flow rate of 100-100000 ml/min Preferred consumption 100-3500 ml/min, and most preferred is a flow 1000-2000 ml/min it is Desirable to apply the sample to the detector continuously. As was shown above, the proposed chromatograph can be placed in a small volume, i.e. it is suitable as a portable analyzer. Thus, one advantage of the invention is the ability to transfer gas chromatograph hands to the place of analysis and/or back.
The idea of the invention consists in the combination of a beam of open tubular capillaries with the detector. The beam effectively separates components of the sample to be analyzed, and the detector will detect. Thus, the invention relates also to the use of a bundle of capillaries of the specified type in conjunction with the detector for separation and analysis of a gaseous sample, and the capillary walls are gas-permeable polymer membrane.
The specified beam can be formed in the form of a dialysis filter, in which the inner wall of the capillary preferably has a large specific surface area. In addition, the beam can be formed in the form of industrial drying apparatus, which corresponds to its original application. In this case, the internal walls of the and capillaries smooth and has a low permeability. In the most preferred form, i.e. in a gas chromatograph, the beam forms a column, and the detector is a detector of the gas chromatograph. Properties such chromatograph described above. Due to its efficiency, the chromatograph is preferable to use as a portable gas analyzer.
If necessary, H.H. block based hollow fiber capillary membranes, combined with the chemical detector according to the invention, can provide the ability of chemical separation, sufficient to substantially facilitate the solution of the problem of cross-sensitivity. Due to the high flow speed of the device can be used without any significant pressure changes or the specified speed, and it is also possible to stabilize rapid changes in humidity and temperature. In addition, it is quite compact, has a low weight and low energy consumption, i.e. suitable for use in mobile applications, and its marginal cost contributes to commercial success.
Brief description of drawings
Figure 1 illustrates the preferred applications of the bundle of hollow fiber capillary membranes that perform the function GC column, combined with the chemical detector.
Figure 2 illustrates one of the preferred embodiments give the tion temperature control for beam hollow fiber capillary membranes, perform the function GC column. The top of figure 2 shows a single hollow fiber; the right - end column in the direction of air flow.
Figure 3 illustrates the result of the filing of the analyzed mixture through a bundle of hollow fiber membranes to the detector.
The implementation of the invention
Figure 1 shows one of the preferred applications of the beam 2 hollow fiber capillary membranes that perform the function GC column, combined with the chemical detector 1. Supply system sample contains a valve 4, a filter 3, an absorbent pair, input 5 for gas and, if necessary, additional valve 6. The position of the valve 4 determines whether the proceeds sample to multicapillary GC column 2 on the basis of the bundle of hollow fibers through the filter (valve 4 is in position (b)) or directly (valve 4 is in position (C)). The switching valve 4 from position (b) position (C) corresponds to the value t=0 for retention time.
Another preferred variant implementation, also shown in figure 1, requires an additional valve 6, which defines the involved whether GC column based on the bundle of hollow fibers (valve 6 is in position (b) or (C)) or not (valve 6 is in position (a)). When the beam is not used (position (a)), the response time can be reduced, however, when applying the beam (valve 6 to the position (b) or (C)the opportunity for more specific identification with a smaller cross-sensitivity.
Figure 2 shows one of the preferred embodiments of the device temperature adjustment for beam 2 hollow fiber capillary membranes that perform the function GC column. The column has a design that is impervious to air, and shell (casing) 14 speakers manufactured (made) from insulation material. Fluid (liquid or gas), for which you can control the temperature and heat flows through the holes 8 and circulates through the casing in the direction 11 by a pump 12. However, the capillary 16 is formed michaelanne space 7. In one of the preferred embodiments fluid michaelango space 7 is a glycerin or industrial cooling solution. In another preferred embodiment, such a medium is the air.
Following the preferred implementation uses a design similar to that shown in figure 2, but in this case, the system or has a heater 13, or it is missing. In the specified embodiment, the role of fluid michaelango space 7 performs the air, and its main function is to clean the system. The air pump only in the entrance 10A column, and on the opposite end of the air provides access 10 through peri is erinya holes 8, i.e. tube (hose) 15 for pumping heating medium is removed (deleted).
In any case, fluid michaelango space 7 is isolated from the gaseous sample device in the form of plugs 26, 17 at the end of the tube. In a preferred embodiment, the filling material 9 at the end of the tube fills only the space between the capillaries and, in addition, binds the capillaries into one. In one of the preferred embodiments the filling material 9 is an epoxy glue.
In one of the preferred embodiments the beam 2 is a bundle of hollow fiber capillary membranes are highly selective of the type used in industrial drying apparatus. The specified device is commercially available under the trademarks Drypoint (Beko), MF-Dryer (CKD, Wilkinson), SF-Serie (Whatman, Balston), Sunsep (Zander, SMC), VarioDry (Ultrafilter) and Porous Media (Norgren). The structure of the capillary wall for this option, shown in figure 2, above. In a typical case, it consists of actually hollow fiber 18 that functions as a base, and a dense active layer (membrane) 19, covering the inner surface.
In one of the preferred embodiments the detector 1 is a combined multi IMS spectrometer commercially available under the trademarks ChemPro100 (Environics), M90-D1-C (Environics), MultiIMS (Drager), or ubai another detector on the basis of the IMS spectrometer.
The following example illustrates but does not limit the main features of the present invention.
Used a device similar to the device shown in figures 1 and 2. The bundle of the hollow fiber membrane of capillaries taken from the membrane-drying apparatus Drypoint (Beko). The detector is a device ChemPro100 (Environics)operating with a flow rate of 1 l/min
The initial moment of time (retention time equal to 0) set the switching valve 4 from position (b) position (C) - see figure 1.
Figure 3 shows the result of the feed of the mixture of methyl salicylate (MeS) and diisopropylethylamine (DIMP) (1% DIMP and 99% MeS) through the bundle of hollow fiber membranes to the detector.
Initially, the detector draws air through the filter and measures the pure background signal. Simultaneously with the beginning of the filing of the sample valve 4 is switched to position (C). 3 with the valve 4 is switched to position (b). Through this procedure, the dose of the sample injected into the fiber in the interval between feeds clean air.
Within 40 seconds both chemical drug was suirable through the column and selectively detected by the ion mobility spectrometer (DIMP) and a gas sensor based on metal oxide (MeS). If the sample was introduced through the valve 6 installed in position (a), between the signals would not be a time delay.
The present invention provides the device is, used as a chemical detector. In the preferred embodiment, it is used as an additional device that conducts chemical separation and combined with any chemical detector. The invention improves the chemical specificity of chemical detectors used equipment consists of inexpensive components and facilitates robust design. It is especially useful when used to identify the presence of chemical warfare agents and other toxic and flammable gases and vapors in applications such as military, industrial or personal protection, occupational health or the environment, as well as the control of production processes.
1. Gas chromatograph for analyzing a sample containing feed system (3-6) for submission of the sample, an open tubular capillary column (2) for separating components of a sample, the device (8-15) temperature control for regulating the temperature of the column (2) and the detector (1) for detecting separated components of the sample, and the specified column (2) contains a bunch of open tubular capillaries, characterized in that the said open tubular capillaries (16) are gas-permeable wall containing polymer membrane (19).
2. Gas chromatograph according to claim 1, characterized in that the submission is t a handheld portable gas chromatograph.
3. Gas chromatograph according to claim 1, characterized in that the wall has an inner layer of polymeric membranes (19)selectively permeable to gases, and the outer layer of a porous polymeric base (18).
4. Gas chromatograph according to claim 1, characterized in that the beam contains 10-10000 open tubular capillaries (16).
5. Gas chromatograph according to claim 1, characterized in that the open tubular capillaries (16) have a length of from 10 to 100 cm and an inner diameter of 10 to 1000 microns.
6. Gas chromatograph according to claim 4, characterized in that the beam contains from 100 to 4000 open tubular capillaries (16).
7. Gas chromatograph according to claim 5, characterized in that the inner diameter of the open tubular capillaries (16) is from 50 to 1000 microns.
8. Gas chromatograph according to claim 1, characterized in that between open tubular capillaries (16) there is a free space.
9. Gas chromatograph according to claim 1, characterized in that the column (2) has a casing (14)surrounding the specified bundle.
10. Gas chromatograph of claim 8, characterized in that the device (8-15) temperature control contains a heating medium (9), designed to flow through a specified space between the capillaries (16).
11. Gas chromatograph of claim 10, characterized in that the device (8-15) temperature control contains the specified casing (14), the cat is which is made of insulating material and has inlet and outlet openings (8), enables the flow of the heating medium (9) through the free space between the capillaries (16).
12. Gas chromatograph according to claim 1, characterized in that the device (8-15) temperature control includes thermostatic heater for regulating the temperature of the heating medium (9).
13. Gas chromatograph according to item 12, characterized in that the device (8-15) temperature control includes a pump (12) and the tube (15) for pumping and transfer of the heating medium (9) between thermostatic heater (13) and the open space between the capillaries (16).
14. Gas chromatograph according to claim 1, characterized in that the conveying system (3-6) includes a filter (3) to absorb vapor from the sample prior to its introduction into the column (2).
15. Gas chromatograph according to claim 1, characterized in that the conveying system (3-6) contains the input (5) for gas, providing the opportunity for the input of the sample in column (2).
16. Gas chromatograph according to 14, characterized in that the conveying system (3-6) includes a valve (4) for feeding the sample to the column (2) directly or through the filter (3).
17. Gas chromatograph according to claim 1, characterized in that the conveying system (3-6) includes a valve (6) to bring the sample to the detector (1) by conducting it through a column (2) or directly.
18. Gas chromatograph according to claim 1, characterized in that the detector (1) is a spectrometer is moveable the STI ions (IMS spectrometer).
19. Gas chromatograph for p, characterized in that the IMS spectrometer is a combined multi IMS spectrometer, designed for through-flow of the sample.
20. Gas chromatograph according to claim 19, characterized in that the detector (1) is made using semiconductor sensors, electro-acoustic gas sensors or matrices, or humidity sensors and temperature, or a combination of any of these sensors.
21. Gas chromatograph according to claim 1, characterized in that the beam of open tubular capillaries refers to the type of beam used in industrial membrane-drying unit.
22. Gas chromatograph according to any one of the preceding paragraphs, characterized in that it is a portable and/or handheld detector.
FIELD: physics, measurements.
SUBSTANCE: proposed method can be used in chemical, petrochemical, medical and other industries to analyse compound mixes of various substances. It differs from known techniques in that as chyral smectic decyloxi-benzylidenamino-2-methyl-butyl-ether of aminocinnamic acid vapor is used as a fixed nematic phase.
EFFECT: higher selectivity of analysis.
FIELD: physics, measurements.
SUBSTANCE: proposed method can be used in chemical, petrochemical, medical and other industries to analyse rapidly the compound mixes of various substances of natural and technogenic origin. The proposed method differs in that immobile liquid-phase film is formed on a solid carrier dynamically pre-applied by periodic metering out of the portion of aerosol of liquid-phase solution in inert gas. The proposed device incorporates a spray gun to produce mist of liquid-phase fluid solution in inert gas and an adjustable air drag bubbler.
EFFECT: higher efficiency of proposed method.
2 cl, 1 dwg
FIELD: physics, measurements.
SUBSTANCE: invention can be used in gas chromatography for quantitative analysis of compound mixes of harmful organic and inorganic substances generated by automotive ICE gas engines. The proposed gas chromatographic system incorporates the device to feed in the pre-concentrated sample, two analytical modules with flame ionisation detector and heat conductivity detector, capillary column to isolate the sample hydrocarbon components, three filled columns, methanator and reactor to reduce nitrogen oxides to total nitrogen in the presence of carbon dioxide.
EFFECT: faster analysis.
FIELD: physics; measurement.
SUBSTANCE: present invention relates to devices for separating a mixture of gases and vapours using gas chromatography method. The device has a carrier gas channel with a pressure regulator, which connects, through a control valve-switch, the reservoir of separated liquid with an intermediate measuring tank, from which a pre-set dose is forced out by the gas-carrier on another channel through a return valve fitted on its outlet and an atomiser into an evaporator. The intermediate measuring tank has concave walls for linearisation of the scale. Inside the reservoir, there is a rotating pipe with an actuator and means of moving in several degrees of freedom. The inlet opening of the rotating pipe can change its level relative the upper level of liquid in the intermediate measuring tank. A batcher, with friction members, stabilises the operational parametres of the device. The evaporation process is controlled and monitored using temperature and pressure sensors, placed in the atomiser and evaporator.
EFFECT: increased efficiency and output of the device.
FIELD: physics; measurement.
SUBSTANCE: present invention pertains to chromatography and is meant for determining total content of oil-products in water. The invention can be used for measuring concentration of oil-product impurities in natural and sewage water during ecological monitoring and other tests on the environmental medium. The method of determining total content of oil-products in water involves putting a sample into a chromatographic column with a stream of carrier gas and subsequent detection in form of a continuous peak using a flame ionisation detector. Before analysis, the contaminated water sample is homogenised, adding, for example, dimethyl sulphoxide. The homogenous sample is pumped through a microconcentrator. Polar components of the sample and the homogenising solvent are removed by pumping pure water. The microconcentrator is put into a chromatograph evaporator and heated using an external heater. Desorption of oil-products takes place using water vapour, generated by a steam generator whose pressure can be regulated.
EFFECT: fast, convenient and accurate determination of total content of oil-products in water media for various domestic purposes.
3 cl, 3 ex, 2 tbl
SUBSTANCE: chromatographic separator of mixed gases and vapours contains three columns with one used to regenerate sorbent layer from heavy mix fraction, and two others used to separate mixture and remove light fraction. Columns are sectioned. Each section is filled sorbent selective to components of separated substance. Light and heavy fraction exhaust lines after fraction tanks through collector and driven switch elements are added with chromatographic modules each containing three columns with one used to regenerate sorbent layer from heavier fraction and two others used to separate mixture and remove light fraction components. Columns are sectioned. Each section is filled sorbent selective to components of separated substance and moving under carrier gas height supplied from the first section and exhausted from the last through offtake passing through column and filled motionless sorbent layer. Number of chromatographic modules to separate binary fractions is proportional to number of these fractions in multicomponent separated mixture. Modules process variable, including temperature, separated fraction volume, sorbent selectivity, column diameter and length are individual.
EFFECT: higher efficiency and productivity of compound multicomponent mixture separation.
SUBSTANCE: novel chemical compound - 4-(4-cyanophenyl)-4'-(4-hydroxyhexyloxy)-benzylidenaniline, which possessing liquid crystalline properties, has wider temperature range of mesophase existence, higher temperature of passing into isotropic liquid (>200°C), demonstrates higher structural selectivity with respect to positional isomers of organic compounds.
EFFECT: increasing gas chromatographic column efficiency and reducing time of separation of positional isomers of organic compounds.
1 ex, 1 tbl
FIELD: chemistry; mechanics.
SUBSTANCE: device consists of serially connected detector, an analytical column, evaporator, device for preparing and inputting samples, as well as a holder for solid samples, three-way tap, the input of which has nozzle for inlet of the carrier gas, while its outputs are connected to the case of an airlock chamber and the solid samples holder respectively. The airlock chamber consists of a case and a swivel head, which have a cylindrical channel of the same diameter. The case of the airlock chamber is fixed to the evaporator such that, the cylindrical channel of the case is a continuation of the channel of the evaporator, and the swivel head is fixed to the case with provision for rotation by a 90° angle. The solid samples holder is in form of container with a calibrated opening.
EFFECT: increased authenticity of identification with simplification of the device and its use at the same time.
FIELD: technological processes.
SUBSTANCE: in suggested device for chromatographic separation of substances at the outlet of eluent with stripped components or fractions of separated substance additionally controlled flow divider is installed, which forms bypass line in relation to the main flow, on which one or several detectors that are selective to components of separated substance. Between flow divider and input to detectors analytical column is installed, the form of structure of which is similar to form of preparative columns, which are arranged in the form of curved distributed surfaces closed in space, and is equipped with dosing device with channel for eluent supply.
EFFECT: increase of efficiency of chromatographic separation.
SUBSTANCE: invention pertains to the quantitative method of determining thymol and carvacrol in medicinal plant raw material, in extracts and infusions of plant raw material using high-performance liquid chromatography. The result is attained by that, in the quantitative measurement of thymol and carvacrol present in the extract, a column with dimensions 250×4.6 mm is used. The column is filled with silica gel with grafted straight alkyl groups, in which the number of atoms equals sixteen (C 16), with particle size of 7 mcm. The mobile phase used is a methanol-water solution with ratio of 62:38. The speed of the mobile phase is 1 ml/min. Detection is done using a UV-detector with wavelength of 277 nm, with subsequent calculation of thymol and carvacrol relative to the area of peaks of the analysed and standard substance. The standard substance used is a standard solution of thymol-carvarol.
EFFECT: method allows for separation and quantitative measurement of content of separate thymol and carvacrol in medicinal raw material, in extracts and infusions of plant raw material, simplifies the sample preparation process, reduces the time of analysing and simplifies identification of the substance.
8 ex, 1 tbl
FIELD: chemical engineering; medical engineering.
SUBSTANCE: method involves plotting two chromatograms one of which is based on radioactivity (No 1) and the other one on ultraviolet absorption (No 2) or on radioactivity (No 1) and on fluorescence (No 2) and chromatogram specific relative to ultraviolet absorption (No 3) or relative to fluorescence (No 3). Material quality is estimated to be the more high the more close studied labeled compound peak shape is to trapezoid shape on the third chromatogram.
EFFECT: high accuracy of the method.
FIELD: analytical chemistry, ecology, in particular controlling of environmental air.
SUBSTANCE: claimed method includes aspiration if air sample through chemosorbtive medium, elution of formed dimethylamine salt, eluate closure with alkali, and gas chromatography analysis of gas phase with flame-ionization detection. Dimethylamine salt elution from adsorbent is carried out with 1 cm3 of distillated water; closured with alkali eluate is held in thermostat for 5 min; and as filling in separating chromatography column chromosorb 103, containing 5 % of PEG-20000 and treated with 20 % hexamethyldisilazane solution is used.
EFFECT: method for dimethylamine detection with improved sensibility and accuracy.
FIELD: chemical industry.
SUBSTANCE: during process of taking sample from technological pipe-line, absorption of water vapors and nitrogen oxides (II) and (IV) are conducted simultaneously. For the purpose the chemical agents are used which don't absorb nitrogen oxide and don't react with it. Chromatographic measurement of volume fraction of nitrogen oxide (I) is carried out by means of industrial chromatograph having heat-conductance detector by using column of thickness of 5 m and diameter of 3 mm. The column is filled with polysorbent; temperature of column's thermostat is 20-30 C and temperature of evaporator is 100C. Hydrogen is used as a gas-carrier. Concentrations of nitrogen oxide, measured by the method, belong to range of 0, 05-0, 50% of volume fraction. Method excludes aggressive affect of corrosion-active components on sensitive parts of chromatograph. Method can be used under industrial conditions for revealing factors influencing process of forming of nitrogen oxide at the stage of catalytic oxidation of ammonia and searching for optimal conditions for minimizing effluent of ammonia into atmosphere.
EFFECT: high reproduction; simplification; improved efficiency of operation.
FIELD: oil and gas production.
SUBSTANCE: aim of invention is estimating expectations for oil and gas of oil-source rock areas. For that aim, sampled rock is treated to isolate organic substance soluble in organic solvents, after which organic substance is chromatographed to detect 4-methyldibenzothiophene and 1-methyldibenzothiophene. When ratio of 4- to 1-isomer exceeds 0.9 rock is regarded as ripened.
EFFECT: increased determination reliability and rapidity.
SUBSTANCE: in the method, hard carrier with system of narrow pores and channels is kept under temperature below height of potential barriers for movement of at least one type of separated molecules.
EFFECT: higher efficiency.
FIELD: investigating or analyzing materials.
SUBSTANCE: gas analyzer comprises chromatographic columns, detectors, unit for preparing air mounted inside the thermostat, unit for control and processing signals, member for sampling, switches of gas flows, pump for pumping gas mixture, and separating passages connected in parallel and provided with the check valve interposed between them. Each of the separating passages is made of absorbing and separating chromatographic columns connected in series, and the pump is connected to the input of the gas line through the electric valve. The gas analyzer can be made of two separating passages and low pressure chromatographic columns.
EFFECT: enhanced quality of analyzing.
2 cl, 1 dwg, 1 ex
FIELD: analytical methods.
SUBSTANCE: to determine methyl alcohol in water, sample to be assayed is preliminarily subjected to distillation with sulfuric acid added in amount required to provide its concentration in mixture to be distilled c(1/2 H2SO4) = 0.002 M, while strippings constitute 6-7% of the volume of sample. Stripped liquid is thrice rinsed with hexane or Nefras at 1:1 hexane (Nefras)-to-strippings ratio. Rinsed material is then introduced into packed column filled with diatomite modified with 1,2,3-tris(β-cyanoethoxy)propane having deposited fixed phase thereon, which phase is prepared by way of consecutively keeping glycerol each time for 4 h at ambient temperature, 100°C, 130°C, 160°C, and 200°C, and then for 8 h at 230°C and for 40 h at 200°C under nitrogen bubbling conditions. Calculation of methanol content is performed taking into consideration calibrating coefficient.
EFFECT: enabled determination of small concentrations of methyl alcohol in water with sufficient selectivity and reliability.
2 cl, 2 tbl, 6 ex
FIELD: analytical chemistry.
SUBSTANCE: invention relates to method for quantitative determination of thiotriazoline and pyracetam in complex drugs by high performance chromatography, wherein silicagel with grafted 3-(chlorodimethyl)-propyl-N-dodecylcarbamate having particle size of 5 mum is used as sorbent; and degassed 0.05 M aqueous solution of potassium dihydrophosphate is used as mobile phase. Mobile phase velocity is 1 ml/min, and column temperature is 30°C. Method of present invention makes it possible to determine content of two abovementioned active ingredients simultaneously.
EFFECT: simplified process of sample preparation.
3 ex, 3 tbl
FIELD: biotechnology, in particular content determination of polymer chitosan molecules, chitosan-chitine polymer molecules and molecules of chitosan-protein complex in finished form of chitosan.
SUBSTANCE: claimed method includes application of high performance chromatography column filled with polyvinylbenzene sorbent with refractometer detector. As eluent and for dissolving of chitosan preparation samples acetic acid aqueous solution is used. Chain-length distribution is determined on the base of first chromatography peak, and polymer molecular content is calculated on the base of area of first, second and third chromatography peaks, divided up to zero line and belonging to polymer chitosan molecules, chitosan-chitine polymer molecules and molecules of chitosan-protein complex, respectively. To calculate chain-length distribution of polymer chitosan molecules separately calibration curve is plotted using dextran polymer standards.
EFFECT: new effective method for determination of polymer chitosan molecules in chitosan preparations.
4 cl, 3 dwg
FIELD: the invention refers to laboratory chromatographic devices for conducting high-speed chromatographic analysis.
SUBSTANCE: the express-chromatron has an injector, a chromatographic column located in a thermostat, a detector, an amplifier of the signal of the detector, an analog-digital converter, a control system, a pneumatic system. The column is fulfilled either in the shape of a short capillary column or either in the shape of a polycapillary column. The injector is fulfilled with possibility of introduction of the test for the time of 5-50 ms. The detector and the amplifier of its signal are fulfilled with possibility of ensuring constant time of no worse then 10-3 sec. The analog-digital converter is fulfilled with possibility of ensuring speed of no less then 200 measurements in a second.
EFFECT: ensures conducting high-speed chromatographic analysis.
11 cl, 2 dwg