RU175332U1 - DEVICE FOR ELECTRONOGRAPHIC AND MASS-SPECTROMETRIC RESEARCH OF COMPONENTS OF SUBSTANCE, SEPARATED BY CHROMATOGRAPH - Google Patents

Abstract

The utility model relates to the field of research and analysis of materials, namely to a device for the electron diffraction study of molecules (their spatial configuration, internuclear distances, valence angles, vibration amplitudes) and mass spectrometric studies (elemental, isotopic, structural) of pure substances obtained by chromatographic separation of the analyzed material. The claimed device for electron diffraction studies of molecules in the gas phase includes series-connected units of a gas chromatograph, molecular separator, gas electron diffraction device and mass spectrometer. Moreover, each of these blocks is connected to a computer, which with the help of a common computer program regulates and controls the operation of each block. The technical result is an increase in the accuracy of all parameters of the molecules determined by an electron diffractometer, and the reliability of the mass spectra of these molecules. 1 ill.

Description

The proposed utility model relates to the field of research and analysis of materials, namely to a device for the electron diffraction study of molecules (their spatial configuration, internuclear distances, valence angles, vibration amplitudes) and mass spectrometric studies (elemental, isotopic, structural) of pure substances that are obtained chromatographic separation of the analyzed material. This device combines 3 independent methods: gas chromatography (GC), mass spectrometry (MS) and gas electron diffraction (HE), and which can be called a gas chromatography mass electron diffraction (CME).

The prior art device is known combining gas chromatography (GC) and gas electron diffraction (GE) [Ewbank J.D. et al. Real-time data acquisition for gas electron diffraction / Review Scientific Instruments, 1984, V. 55, page 1598; Ewbank J.D. et al. Improvements in real-time data acquisition for gas electron diffraction / Review Scientific Instruments, 1986, V. 57, page 967; Ewbank J.D. et al. On-line gas electron diffraction identification of gas chromatography effluents (GC-GED) / Review Scientific Instruments, 1988, V. 59, page 1144].

As the disadvantages of the device, combining GC and GE, it should be noted the impossibility of obtaining mass spectra of the studied samples (substances).

The connection of a gas electron diffraction device (HE) and a mass spectrometer (MS) is implemented in the device described in [Tremel Y. et al. Connection of a quadrupole mass spectrometer to an electron diffraction device / PTE, 1978, No. 4, P. 251-252; Girichev G.V. et al. Modernization of the EMR-100 electron diffractometer for gas research / PTE, 1984, No. 2, P. 167-169].

A disadvantage of the device combining GE and MS is that there is no separation of the samples under study by gas chromatography, as a result of which the obtained electron diffraction pattern may be the result of electron diffraction from a mixture of molecules: monomers, dimers, and generally any isomers and impurities that may be in the gas phase of the sample. The same can be said about mass spectra: the mass spectra of a mixture of possible isomers and impurities in the gas phase of the sample are superimposed.

The technical result of the proposed utility model is to increase the accuracy of all parameters of the molecules determined using an electron diffractometer (i.e., a more accurate electron diffraction study).

The technical result is achieved by a device for electron diffraction analysis of molecules in the gas phase, including serially connected blocks of a gas chromatograph, molecular separator, gas electron diffraction device and mass spectrometer, each of these blocks being connected to a computer that regulates and controls the operation of each using a common computer program block.

Thus, the proposed device combines gas chromatography (GC), mass spectrometry (MS) and gas electron diffraction (GE). Using this device, you can previously divide the analyzed sample into those components of which it can consist (impurities, isomers, unstable molecules), and then get an electron diffraction pattern and a mass spectrum from each of them. Information obtained from MS and GE allows one to determine to which components the sample under study was separated by a chromatograph, and then determine the spatial structure of the molecule, internuclear distances, valence angles, and vibration amplitudes of the nuclei of the components that make up the gas sample under study (interpretation of electron diffraction patterns). In addition, each unit is connected to a computer that monitors and controls their operation. The results of each unit are transferred to the combined resulting computer program, which, with their account, decrypts the electron diffraction pattern and gives the final result.

In FIG. 1 presents a structural diagram of the proposed device.

The test sample 1, together with the carrier gas 2, enters the gas chromatograph 3. Using a gas chromatograph, the analyzed sample is separated into individual components of which the sample can consist (including isomers and possible impurities). Helium is usually used as the carrier gas, which practically does not contribute to the electron diffraction pattern. From the gas chromatograph 3, where the gas is at a pressure close to atmospheric pressure, the test gas sample together with the carrier gas enters the molecular separator 4, which separates most of the carrier gas from the sample gas. The pressure of the mixture of separated gases decreases to values of the order of ≈ 100 Pa (1 - 0.1 mm Hg). This process is used in chromatography-mass spectrometry and may vary depending on the properties of the sample and the design of the molecular separator.

The components of the sample gas and the remainder of the carrier gas separated in space and time pass through the electron diffuser 5 to the diffraction chamber 5 _{1 of the} electron diffraction device, which also contributes to the separation of light helium from the heavier molecules of the test sample. In the diffraction chamber of the electron diffractor, the electron beam 5 ₂ interacts with the test gas exiting the electron diffuser 5 in the direction perpendicular to the direction of the electron beam 5 ₂ . An electron beam 5 _{2 is} obtained using an electron gun 5 ₃ and an adjustment unit 5 _{4 of an} electron diffractometer. The resulting electron diffraction pattern from each component of the analyzed sample is recorded by the electron detector 5 _{5 of the} electron diffraction device and stored in the memory of the computer 7 connected to this detector. Details of recording an electron diffraction pattern by combining a gas chromatograph and a gas electron diffractometer are known and implemented in [Ewbank JD et al. Real-time data acquisition for gas electron diffraction / Review Scientific Instruments, 1984, V. 55, page 1598; Ewbank JD et al. Improvements in real-time data acquisition for gas electron diffraction / Review Scientific Instruments, 1986, V. 57, page 967; Ewbank JD et al. On-line gas electron diffraction identification of gas chromatography effluents (GC-GED) / Review Scientific Instruments, 1988, V. 59, page 1144]. From the diffraction chamber 5 _{1 of the} electron diffraction apparatus, the sample gas is directed to the ion source of the mass spectrometer 6, then to the analyzer 6 _{1 of the} mass spectrometer, where the ions are separated by the ratio of mass to charge, after which the ion currents are successively measured by the detector 6 _{2 of the} mass spectrometer, which gives the mass spectrum of the separated GC sample. All blocks are tightly connected by flanges through vacuum gaskets. Comparison of the obtained mass spectra with the catalogs of mass spectra of pure substances will allow us to determine the structural formulas of these substances, which will provide additional valuable information when processing electron diffraction patterns. The resulting electron diffraction patterns are stored by a computer and then processed using the appropriate programs. The same can be said about the obtained mass spectra: they are stored by a computer and then compared with the catalogs of mass spectra in order to identify substances separated by the GC of the test sample. If the mass spectrum is not in the catalog, then its decryption is carried out on the basis of currently existing methods (isotopic, elemental, fragmentary, molecular ion, a set of rules in mass spectrometry). The alleged chemical formula is transferred to a computer to decrypt the received electron diffraction pattern. In the event of a successful decryption, the mass spectrum is cataloged.

Claims (1)

A device for electron-diffracting studies of molecules in the gas phase, which includes series-connected blocks of a gas chromatograph, molecular separator, gas electronograph, and mass spectrometer, each of these blocks being connected to a computer that controls and controls the operation of each block using a common computer program.

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