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EP-4741814-A1 - METHOD FOR DETECTING PRESENCE OR ABSENCE OF POLYCYCLIC AROMATIC HYDROCARBONS

EP4741814A1EP 4741814 A1EP4741814 A1EP 4741814A1EP-4741814-A1

Abstract

A method can be provided that can individually detect some PAHs and speed up analysis by a method for detecting the presence or absence of a predetermined PAH (molecular formula: M), the method including: step 1 of chromatographically separating a sample containing the PAH; step 2-1 of generating at least one of [M+CH 3 ] + , [M+C 2 H 5 ] + , and [M+C 3 H 5 ] + as a precursor ion by ionization of the PAH using a chemical ionization method with introduction of methane gas, or step 2-2 of generating at least one of [M+CH] + , [M+HNC 2 ] + , and [M+H 2 NC 2 ] + as a precursor ion by ionization of the PAH using a solvent mediated chemical ionization method with introduction of acetonitrile; step 3 of generating a fragment ion derived from the precursor ion; and step 4 of detecting the presence or absence of the PAH based on the presence or absence of the fragment ion.

Inventors

  • ISHII, Toshinari

Assignees

  • Shimadzu Corporation

Dates

Publication Date
20260513
Application Date
20240604

Claims (12)

  1. A method for detecting the presence or absence of a predetermined polycyclic aromatic hydrocarbon (molecular formula: M), the method comprising: step 1 of chromatographically separating a sample containing the polycyclic aromatic hydrocarbon; step 2-1 of generating at least one of [M+CH 3 ] + , [M+C 2 H 3 ] + , and [M+C 3 H 5 ] + as a precursor ion by ionization of the polycyclic aromatic hydrocarbon using a chemical ionization method with introduction of methane gas, or, step 2-2 of generating at least one of [M+CH] + , [M+HNC 2 ] + , and [M+H 2 NC 2 ] + as a precursor ion by ionization of the polycyclic aromatic hydrocarbon using a solvent mediated chemical ionization method with introduction of acetonitrile; step 3 of generating a fragment ion derived from the precursor ion; and step 4 of detecting the presence or absence of the polycyclic aromatic hydrocarbon based on the presence or absence of the fragment ion.
  2. The method according to claim 1, wherein the precursor ion generated in the step 2-1 is at least one of [M+C 2 H 5 ] + and [M+C 3 H 5 ] + .
  3. The method according to claim 1, wherein the polycyclic aromatic hydrocarbon is chrysene.
  4. The method according to claim 3, wherein the precursor ion generated in the step 2-1 is [M+C 2 H 5 ] + .
  5. The method according to claim 3 or 4, wherein the fragment ion generated in the step 3 after the step 2-1 has a mass number of 215.
  6. The method according to claim 1, wherein the polycyclic aromatic hydrocarbon is chrysene and triphenylene, and in the step 4 after the step 2-1 and the step 3, the presence or absence of chrysene or triphenylene is detected based on the presence or absence of the fragment ion.
  7. The method according to claim 6, wherein in the step 4 after the step 2-1 and the step 3, if the fragment ion is present, it is determined that at least chrysene is present.
  8. The method according to claim 6, wherein in the step 4 after the step 2-1 and the step 3, if the fragment ion is absent, it is determined that at least chrysene is not present.
  9. The method according to claim 1, wherein the polycyclic aromatic hydrocarbon is benzo[b]fluoranthene, benzo[k]fluoranthene, or benzo[j]fluoranthene.
  10. The method according to claim 9, wherein the precursor ion generated in the step 2-1 is [M+C 2 H 5 ] + .
  11. The method according to claim 10, wherein the fragment ion generated in the step 3 after the step 2-1 has a mass number of 266 for benzo[b]fluoranthene, 225 for benzo[k]fluoranthene, or 253 for benzo[j]fluoranthene.
  12. The method according to claim 1, wherein the polycyclic aromatic hydrocarbon is phenanthrene and anthracene, and in the step 4 after the step 2-2 and the step 3, the presence or absence of phenanthrene or anthracene is detected based on the presence or absence of the fragment ion.

Description

TECHNICAL FIELD The present invention relates to a method for detecting the presence or absence of a polycyclic aromatic hydrocarbon. BACKGROUND ART Polycyclic Aromatic Hydrocarbons (PAHs) are a group of compounds in which two or more benzene rings are fused. They are unintentionally generated by incomplete combustion or thermal decomposition of organic matter and are contained in food and environmental water due to food processing/cooking processes or contamination from the environment. Benzo[a]pyrene, a representative substance, has carcinogenicity, and some other PAHs are also suspected of having carcinogenicity (see, for example, the Ministry of Agriculture, Forestry and Fisheries website [searched April 19, 2023], Internet <URL: https://www.maff.go.jp/j/syouan/seisaku/risk_analysis/priority/hazard_chem.html> (Non-Patent Literature 1)). For these reasons, several types of PAHs are regulated in Japan and abroad, and separation analysis methods by Gas Chromatography-Mass spectrometry (GC/MS) and Liquid Chromatography-Mass spectrometry (LC/MS) are mainstream. Many PAHs have similar structures, and their physical properties such as mass, polarity, and boiling point are close. Due to these characteristics, mass separation by ionization is insufficient, and it is common to separate them by chromatogram using several different types of columns. PAHs have multiple isomers due to differences in the fusion position of the benzene rings. For these isomers, ionization methods such as Electron Ionization (EI), Positive Chemical Ionization (PCI), and Atmospheric Pressure Chemical Ionization (APCI) do not produce differences in their mass spectra. As mentioned above, the physical properties that characterize the compounds are also similar, making chromatographic separation difficult and hindering the quantification of regulated components. Here, FIG. 7(a) shows the results of chromatographic separation of triphenylene and chrysene by a conventional GC method. In particular, chrysene and triphenylene, which have a molecular weight of 228, are considered difficult to separate, and it is necessary to use different columns suitable for their respective separation. Chrysene is regulated in various countries in the food and environmental fields, but triphenylene is not, making their separation extremely important to prevent misidentification of chrysene. Furthermore, FIG. 7(b) shows the mass spectra of triphenylene and chrysene by a conventional EI method. Triphenylene and chrysene not only co-elute chromatographically but also have the same fragment ions when ionized by EI, PCI, APCI, etc., making the separation of isomers using a mass spectrometer difficult. No differences are found in their Ultraviolet (UV) absorption wavelengths, excitation wavelengths, or Infrared (IR) absorption spectra, and isomers cannot be distinguished by spectroscopic methods either. CITATION LIST NON-PATENT LITERATURE [Non-Patent Literature 1] Ministry of Agriculture, Forestry and Fisheries website [searched April 19, 2023], Internet <URL: https://www.maff.go.jp/j/syouan/seisaku/risk_analysis/priority/hazard_chem.html>[Non-Patent Literature 2] John Oostdijk, Agilent Technologies, Inc., Application News SI-002959 "Fast Separation of EU and US EPA Regulated PAHs on Agilent J&W Select PAH GC Columns", 2010.[Non-Patent Literature 3] Yoshio Iida et al., "Quantification of Trace Impurities in Benzene by Gas Chromatography-Chemical Ionization Mass Spectrometry," Mass Spectrometry, Vol. 24, No. 4, 1976[Non-Patent Literature 4] Kenji Arikawa et al., "Ion-Molecule Reactions of CH5+, C2H5+, C3H5+ with Halogenated Benzenes in an Ion Trap Mass Spectrometer," Journal of the Mass Spectrometry Society of Japan, (2011), doi: 10.5702/massspec. 11-21[Non-Patent Literature 5] Colleen K. Van Pelt et al., "Studies of structure and mechanism in acetonitrile chemical ionization tandem mass spectrometry of polyunsaturated fatty acid methyl esters | Journal of the American Society for Mass Spectrometry", J Am Soc Mass Spectrom 1999, 10, 1253-1262[Non-Patent Literature 6] Xiang Zhang., "Gas-phase cleavage of the novel iminium ions [R1-CH+-N=CH-R2←→R1-CH=N+=CH-R2]: An experimental and computational study", Journal of Molecular Structure 1056-1057 (2014) 219-226 SUMMARY OF INVENTION TECHNICAL PROBLEM The present invention has been made to solve the above problems, and an object thereof is to provide a method that can individually detect some PAHs and can speed up analysis. [SOLUTION TO PROBLEM] A first aspect of the present invention relates to a method for detecting the presence or absence of a predetermined polycyclic aromatic hydrocarbon (molecular formula: M), the method including: step 1 of chromatographically separating a sample containing the polycyclic aromatic hydrocarbon,step 2-1 of generating at least one of [M+CH3]+, [M+C2H3]+, and [M+C3H5]+ as a precursor ion by ionization of the polycyclic aromatic hydrocarbon using a chemical ionization method with introducti