Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
  • G01N27/622—Ion mobility spectrometry
  • G01N27/624—Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
  • G01N27/416—Systems
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/62—Detectors specially adapted therefor
  • G01N30/72—Mass spectrometers
  • G01N30/7206—Mass spectrometers interfaced to gas chromatograph

Definitions

• the present invention relates to the field of gas analysis and is intended to detect microimpurities of substances in gaseous media, in particular an atmosphere of air, is used in gas chromatography as a sensitive detector.
• instruments based on the method of detection by ion mobility are used to control the microconcentrations of impurities of organic and inorganic substances in gases.
• this device In the case of ionization at atmospheric pressure, this device has low sensitivity and noise immunity due to the influence of impurities in the analyzed gas on the ionization efficiency and separation efficiency.
• the heating chamber is installed at the entrance of the ionization chamber, connected at the input to the analyzed gas and the output of the gas purification device, and at the exit, at the entrance to the ionization chamber and includes a temperature meter, a temperature controller and a humidity meter, which is connected to a controlled gas discharge device.
• This spectrometer is disclosed in the patent of the Russian Federation N 2 2178929, publication date - 01/27/2002, the IPC index - H01J49 / 40.
• the disadvantage of this device is that it does not solve the problem of protecting the ionizer from the effects of impurities contained in the analyzed gas.
• the closest technical solution of the present invention is still an ion mobility spectrometer according to the aforementioned US patent N 2 5420424.
• the disadvantage of this technical solution is the exposure of the ionizer in the stream of the analyzed gas. This leads to instability of the formation of reactant ions, as well as to a change in the ionizer current over time due to contamination of the ionizer with the analyzed gas.
• the present invention is to protect the ionizer from contamination of the analyzed gas.
• the technical result of the present invention is to improve the stability and reproducibility of the results of the analysis of gas environments, increasing the life of the ionizer.
• a differential ion mobility spectrometer including a cylindrical ionization chamber in which analyte ions are formed, having an input for the analyzed gas and an outlet for gas discharge, an ionization source, an ion aperture, an electrode system consisting of two concentrically arranged internal and external electrodes, an analytical gap formed by these two opposite cylindrical electrodes, having an input for purified gas, connected at the input to the analyte ion formation region through an ion aperture, and at the output to an ion recorder, a periodic polarity asymmetric generator, providing access to the plot of the nonlinear field dependence of ion mobility, a compensating voltage generator, a high-frequency voltage source, providing an increase in the resolution of the device, connected to the internal electrode, according to the invention, is equipped with an additional chamber concentrically located relative to the inner cylindrical electrode, having an input and output for the ionizing gas, in which the ionization source is located and the repulsive voltage generator is
• a radioactive? Source such as tritium, can be used as an ionization source to produce negative and positive ions.
• an electron ionizer for example, a corona discharge
• an ionization source for which an electrode with a sharp end connected to an alternating high voltage generator is placed in an additional chamber.
• an electrospray can be used as an ionization source in the spectrometer according to the present invention, for which an electrospray capillary is placed in an additional chamber to supply a solution of a controlled flow rate and composition connected to a constant high voltage source.
• any known source of ultraviolet radiation can be used as an ionization source.
• a gas purification system may contain a gas flow inducer (for example, a pump), two filters located at the outlet of the ionization chamber and at the entrance to the analytical gap and an additional chamber, three pneumatic resistances installed after the filters and at outlet E to discharge gas into the atmosphere.
• a gas flow inducer for example, a pump
• two filters located at the outlet of the ionization chamber and at the entrance to the analytical gap and an additional chamber
• three pneumatic resistances installed after the filters and at outlet E to discharge gas into the atmosphere.
• the Figure shows a diagram of a spectrometer of the present invention.
• the present invention organizes an additional stream of purified gas with a controlled composition around the ionizer. Then, the resulting reactant ions are mixed with the flow of the analyzed gas and the ions of the analytes are formed as a result of ion-molecular recharging reactions with the reactant ions.
• the spectrometer consists of an ionization chamber 1, an external cylindrical electrode 2 and an inner cylindrical electrode 3, concentrically located relative to the electrode 2, an additional chamber 4 for introducing a stream of ionized gas (reactant gas), concentrically located relative to the inner cylindrical electrode 3, an ionization source 5, for example of a radioactive?
• a -source located at the output of chamber 4, of a generator 6 of a periodic voltage asymmetric in polarity, providing access to the current of the nonlinear field dependence of the mobility of ions, a compensating voltage generator 7, a high-frequency voltage source 8, providing an increase in the resolution of the device connected to the electrode 3, a buoy voltage generator 9 connected to the chamber 4, an ion collector 10 located at the end of the analytical gap 1 1, to which an ion recorder 12 is connected, for example, a current meter.
• Chamber 1 and the internal electrode 3 are separated from each other and form an ionic aperture 15, which allows ionized particles to move into the analytical gap 1 1.
• the ionization chamber 1 has an inlet 17 for introducing a stream of the analyzed gas and an outlet 18 for discharging gas.
• the spectrometer is equipped with a gas purification system that combines the 19 outputs of the analytical gap 1 1 and the ionization chamber 1 with the inputs of the additional chamber 4 and the analytical gap 1 1.
• the gas purification system includes a gas flow inducer (for example, a pump) 25, two filters 23 and 24, respectively placed at the exit of the ionization chamber 1 and at the entrance to the analytical gap 1 1 and the additional chamber 4, three pneumatic resistances 20, 21, 22, installed after the filters 23 and 24 and at the exit E to discharge gas into the atmosphere.
• a gas flow inducer for example, a pump
• two filters 23 and 24 respectively placed at the exit of the ionization chamber 1 and at the entrance to the analytical gap 1 1 and the additional chamber 4
• three pneumatic resistances 20, 21, 22, installed after the filters 23 and 24 and at the exit E to discharge gas into the atmosphere.
• Cylindrical electrodes and chambers are separated from each other by supporting elements 26.
• the spectrometer works as follows.
• Reactant ions are formed in the ionized purified gas stream R entering the chamber 4 under the influence of ⁇ particles of the radioactive source 5 in the ionization region 13. Reactant ions enter the stream of the analyzed gas A entering the ionization chamber 1 through the inlet 17. At the same time, the stream of the purified buffer gas B enters the space between the wall of the chamber 1 and the electrode 2. A part of this stream exits through the ion aperture 15 to the region of formation of the analyte ions 14 , the other part C enters the analytical gap 1 1 formed by electrodes 2 and 3.
• the ions of the analyzed substances are formed as a result of ion-molecular recharging reactions and are pulled by an electric field, provided by the potential difference between the electrodes 3 and 2 from the region of formation of ions 14, into the carrier gas stream C. Ions with different dependence of mobility on the electric field intensity reach the ion collector 10 at the end of the gap 1 1 at various compensating voltages and are recorded by a current meter 12.
• the gases passed through the collector 10 and the outlet 18 of the ionization chamber 1 enter the purification system. After cleaning, one stream of purified gas is returned to the chamber 4, and the other in the analytical gap 1 1.
• the technical result of the present invention is due to the fact that the flow of ionizing clean gas prevents the analyzed "dirty" gas from entering the ionization source.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Electron Tubes For Measurement (AREA)

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• 2012
  • 2012-05-22 RU RU2012121133/07A patent/RU2503083C1/ru active
• 2013
  • 2013-04-25 CN CN201380004790.4A patent/CN104054156B/zh not_active Expired - Fee Related
  • 2013-04-25 DE DE112013000365.1T patent/DE112013000365B4/de not_active Expired - Fee Related
  • 2013-04-25 WO PCT/RU2013/000359 patent/WO2013176580A1/fr not_active Ceased

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