Chemical ionization and photoionization composite source mass spectrometer-based volatile organic matter detection device and detection method

Abstract

The invention relates to a chemical ionization and photoionization composite source mass spectrometer-based volatile organic matter detection device and detection method. The device comprises a discharge ion source, photoionization lamps, a reaction tube with a gradually-decreasing inner diameter, a transition cavity, a mass spectrometer cavity, a transition cavity molecular pump, a mass spectrometer cavity molecular pump, a fore pump, an alternating current/direct current composite power source, a sample injection opening, an ion detection mass spectrometer, a gas source and the like. According to the detection method of the invention, chemical ionization and photoionization of ion and molecular reaction are adopted, so that the simultaneous dual ionization of various volatile organic matters can be realized; the mass spectrometer is adopted to realize online high-sensitivity detection; and since the multi-dimensional ionization and high-sensitivity mass spectrometry detection of thevolatile organic matters are realized by chemical ionization and photoionization, the defect of difficulty in detecting alkane volatile organic matters of chemical ionization such as proton transfer reactions and the defect of low efficiency under a vacuum condition of photoionization can be eliminated; and full-coverage, high-sensitivity, simultaneous and on-line detection of non-alkane volatileorganic matters and alkane volatile organic matters can be realized.

Description

technical field [0001] The invention belongs to the field of analysis and detection, and in particular relates to a volatile organic compound detection device and a detection method for chemical ionization and photoionization composite source mass spectrometry. Background technique [0002] Proton transfer reaction mass spectrometry is a newly developed chemical ionization mass spectrometry technology based on the ion-molecular reaction. Its most commonly used reactive ion is H 3 o + . If the proton affinity of the volatile organic compound M to be measured is higher than that of H 2 The proton affinity of O is high, so it can be combined with H 3 o + A proton transfer reaction (H 3 o + +M—>MH + +H 2 O), is ionized to MH + . MH + Finally, it can be detected by mass spectrometry to obtain molecular weight information and concentration information. Due to the advantages of high sensitivity, fast response, soft ionization, and no need for calibration, this techno...

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Problems solved by technology

[0004] The technology of the present invention solves the problem: Overcoming the inability of the prior art to carry out simultaneously full-coverage high-sensitivity online detection of alkane and non-alkane organic compounds in the atmosphere, it provides a chemical ionization and photoionization combined source mass spectrometry volatile organic compound detection Device and detection method, prepare reaction ion H by discharging ion source 3 o + 、CH 5 + or NH 4 + As the reaction ions, they are respectively introduced into the reaction tube under the action of an electric field, and the non-alkane organic matter in the gas to be measured undergoes a proton transfer reaction with the reaction ions in the reaction tube to achieve efficient ionization of the non-alkane organic matter; the photoionization lamp passes through the photoelectric The ionization method can carry out high pressure ionization of alkane volatile organic compounds

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