Method for detecting presence or absence of polycyclic aromatic hydrocarbons

Abstract

The present invention provides a method for detecting the presence or absence of specific PAHs (molecular formula: M), the method comprising: a step 1 in which a sample containing the PAHs is subjected to chromatographic separation; a step 2-1 in which at least one of [M+CH3]+, [M+C2H5]+, and [M+C3H5]+ is generated as a precursor ion by means of ionization of the PAHs using a chemical ionization method by introducing a methane gas, or a step 2-2 in which at least one of [M+CH]+, [M+HNC2]+, and [M+H2NC2]+ is generated as a precursor ion by means of ionization of the PAHs using a solvent-mediated chemical ionization method by introducing acetonitrile; a step 3 in which a fragment ion derived from the precursor ion is generated; and a step 4 in which the presence or absence of the PAHs is detected on the basis of the presence or absence of the fragment ion. With this method, it is possible to separately detect some PAHs and to speed up the analysis.

Description

Methods for detecting the presence of polycyclic aromatic hydrocarbons

[0001] The present invention relates to a method for detecting the presence or absence of polycyclic aromatic hydrocarbons.

[0002] Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds consisting of two or more bonded benzene rings. They are unintentionally produced through incomplete combustion or thermal decomposition of organic matter, and are found in food and environmental water during food processing and cooking, or as a result of environmental contamination. Benzo[a]pyrene, a representative PAH, is carcinogenic, and some other PAHs are also suspected of being carcinogenic (see, for example, the Ministry of Agriculture, Forestry and Fisheries website [searched April 19, 2023] and the Internet <URL: https: / / www.maff.go.jp / j / syouan / seisaku / risk_analysis / priority / hazard_chem.html> (Non-Patent Document 1)).

[0003] For these reasons, several types of PAHs are regulated both domestically and internationally, and separation and analysis methods using gas chromatography-mass spectrometry (GC / MS) and liquid chromatography-mass spectrometry (LC / MS) are the mainstream. Many PAHs have similar structures and similar physical properties such as mass, polarity, and boiling point. Due to these characteristics, mass separation by ionization is insufficient, and separation is often performed using several types of columns and chromatograms.

[0004] PAHs exist as multiple homologues due to differences in the bonding position of the benzene ring. These isomers do not show any difference in mass spectra when ionized using Electron Ionization (EI), Positive Chemical Ionization (PCI), Atmospheric Pressure Chemical Ionization (APCI), etc. As mentioned above, the physical properties that characterize the compounds are similar, making chromatographic separation difficult, and quantifying regulated components difficult.

[0005] Figure 7(a) shows the results of chromatographic separation of triphenylene and chrysene using conventional GC. Chrysene and triphenylene, both with molecular weights of 228, are particularly difficult to separate, requiring the use of appropriate columns for each. While chrysene is regulated in various countries in the food and environmental sectors, triphenylene is not. Separation of these two compounds is crucial to prevent misidentification of chrysene. Figure 7(b) shows the mass spectra of triphenylene and chrysene obtained using conventional EI. Triphenylene and chrysene not only exhibit similar chromatographic separation, but also produce identical fragment ions when ionized with EI, PCI, APCI, etc., making the separation of homologs using a mass spectrometer difficult. No differences were found in the ultraviolet (UV) absorption wavelength, excitation wavelength, or infrared absorption (IR) spectra, making it impossible to distinguish between homologs using spectroscopy.

[0006] 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> 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. Yoshio Iida et al., “Quantitative Analysis of Trace Impurities in Benzene by Gas Chromatography-Chemical Ionization Mass Spectrometry”, Mass Analysis, Vol. 24, No. 4, 1976. Takeshi Arikawa et al., “Ion-Molecule Reactions of CH5+, C2H5+, and C3H5+ with Halogenated Benzenes in an Ion Trap Mass Spectrometer”, Journal of the Mass Spectrometry Society of Japan, (2011), doi: 10.5702 / massspec. 11-21Collen 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, 1253-1262Xiang 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

[0007] The present invention has been made to solve the above problems, and an object of the present invention is to provide a method that can individually detect some PAHs and speed up analysis.

[0008] A first aspect of the present invention is a method for detecting the presence or absence of a predetermined polycyclic aromatic hydrocarbon (molecular formula: M), comprising the steps of: 1) chromatographically separating a sample containing the polycyclic aromatic hydrocarbon; 2) introducing methane gas and ionizing the polycyclic aromatic hydrocarbon using a chemical ionization method to obtain [M+CH ３ ] ＋ , [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ or, by introducing acetonitrile and ionizing the polycyclic aromatic hydrocarbon using solvent-mediated chemical ionization, [M+CH] ＋ , [M+HNC ２ ] ＋ , [M+H ２ NC ２ ] ＋ a step 2-2 of generating at least one of the above as a precursor ion; a step 3 of generating fragment ions derived from the precursor ion; and a step 4 of detecting the presence or absence of the polycyclic aromatic hydrocarbon based on the presence or absence of the fragment ion.

[0009] The method of the present invention enables the individual detection of some PAHs, thereby speeding up analysis. In particular, it shortens the heating time required to separate chrysene and triphenylene. Furthermore, when acetonitrile is introduced and solvent-mediated chemical ionization is used, phenanthrene and anthracene can also be separated, further improving analytical efficiency. Furthermore, it reduces the probability of false positives due to misidentification, even in food samples with complex contaminants, such as polycyclic aromatic compounds. Furthermore, qualitative analysis of aromatic compounds is possible by applying the ratio of special precursor ions derived from aromatic compounds.

[0010] The figure shows the results of analyzing a mixed standard of chrysene (10 ppm) and triphenylene (10 ppm) using chemical ionization (CI)-MS / MS with methane gas. The figure shows the results of analyzing a mixed standard of chrysene (10 ppm) and triphenylene (10 ppm) using solvent-mediated chemical ionization (SMCI)-MS / MS with acetonitrile. The figure shows the results of analyzing a mixed standard of phenanthrene (10 ppm) and anthracene (10 ppm) using SMCI-MS / MS with acetonitrile. This figure shows an example of applying the method of the present invention to an analytical method using a J&W Select PAH column, as described in 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. The figure shows the results of analyzing a mixed standard of benzo[b]fluoranthene (10 ppm), benzo[k]fluoranthene (10 ppm), and benzo[j]fluoranthene (10 ppm) using CI-MS / MS with methane gas introduction. Figure 5(a) shows the results for 281.0 > 266.0, Figure 5(b) shows the results for 281.0 > 225.0, and Figure 5(c) shows the results for 281.0 > 253.0. The results of analyzing a mixed standard of benzo[b]fluoranthene (10 ppm), benzo[k]fluoranthene (10 ppm), and benzo[j]fluoranthene (10 ppm) using SMCI-MS / MS with acetonitrile are shown in Figure 6(a), where Figure 6(b) shows the results for 288.0 > 276.0, Figure 6(b) shows the results for 288.0 > 265.0, and Figure 6(c) shows the results for 306.0 > 289.0. Figure 7(a) shows the results of chromatographic separation of triphenylene and chrysene by conventional GC, and Figure 7(b) shows the mass spectra of triphenylene and chrysene by conventional EI.

[0011] A first aspect of the present invention is a method for detecting the presence or absence of predetermined PAHs (molecular formula: M), comprising: a step 1 of chromatographically separating a sample containing the PAHs; and a step 2 of introducing methane gas and ionizing the PAHs using CI to obtain [M+CH ３ ] ＋ , [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ Step 2-1: generating at least one of the precursor ions [M + CH] by ionizing the PAHs using SMCI with the introduction of acetonitrile. ＋ , [M+HNC ２ ] ＋ , [M+H ２ NC ２ ] ＋ a step 2-2 of generating at least one of the above as a precursor ion; a step 3 of generating fragment ions derived from the precursor ion; and a step 4 of detecting the presence or absence of the PAHs based on the presence or absence of the fragment ions.

[0012] In a first aspect of the present invention, CI-MS / MS is used to generate characteristic fragment ions for each PAH homologue, and the PAHs are separated by mass separation. This enables individual detection of some PAHs, speeding up analysis and, in particular, shortening the heating time required for separation of chrysene and triphenylene. The first aspect of the present invention can be broadly divided into a case where a CI-MS / MS method is used in which methane gas is introduced (a case where steps 1, 2-1, 3, and 4 are carried out) and a case where an SMCI-MS / MS method is used in which acetonitrile is introduced (a case where steps 1, 2-2, 3, and 4 are carried out).

[0013] [1] CI-MS / MS Method with Methane Gas Injection FIG. 1 shows the results of analyzing a mixed standard of chrysene (10 ppm) and triphenylene (10 ppm) by chemical ionization (CI)-MS / MS (more specifically, PCI-MS / MS) with methane gas injection. In this way, by using CI-MS / MS with methane gas injection, it is possible to individually detect chrysene and triphenylene, which was previously difficult. The CI-MS / MS method with methane gas injection itself is a known technique, and for example, Yoshio Iida et al., "Quantitative Determination of Trace Impurities in Benzene by Gas Chromatography-Chemical Ionization Mass Spectrometry," Mass Analysis, Vol. 24, No. 4, 1976 (Non-Patent Document 3), Takeshi Arikawa ...) ３ ＋ , C ２ H ５ ＋ , C ３ H ５ ＋ Based on known literature such as "Ion-molecule reactions of benzenes with halogenated benzenes," Journal of the Mass Spectrometry Society of Japan, (2011), doi: 10.5702 / massspec. 11-21 (Non-Patent Document 4), a commercially available product (for example, a GCMS-TQ （商標） 8050 NX (Shimadzu Corporation), GCMS-TQ （商標） This can be performed under appropriate conditions using a 8040 NX (Shimadzu Corporation). Figure 1 shows the results of a CI-MS / MS method in which methane gas was introduced under the following conditions: vaporizer temperature: 275°C; carrier gas control: column flow rate (1.00 mL / min); column: Rxi-PAH (60.0 m x 0.25 mm I.D. x 0.10 μm); column temperature: 200°C (1 min) → (10°C / min) → 300°C (10 min); transfer line temperature: 250°C; ion source temperature: 230°C; collision energy: 10 eV. Note that the above conditions are merely examples and are not limited to these.

[0014] In step 1, a sample containing PAHs is first chromatographically separated. In this case, suitable examples of PAHs include, but are not limited to, chrysene, triphenylene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene. Suitable examples of columns used for chromatographic separation in step 1 include, but are not limited to, the above-mentioned Rxi-PAH (manufactured by Restek Corporation), SH-I-XLB (manufactured by Shimadzu Corporation), and SH-I-17Sil MS (manufactured by Shimadzu Corporation).

[0015] In step 2-1, PAHs (molecular weight: M) are ionized using a CI method with the introduction of methane gas to obtain [M+CH ３ ] ＋ , [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ The CI method is a softer ionization method than the EI method, and this method produces at least one of [M+H] as a precursor ion. ＋ , [M+CH ３ ] ＋ When methane gas is introduced, precursor ions such as [M+H] are observed. ＋ , [M+CH ３ ] ＋ In addition to [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ is observed.

[0016] The precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ It is preferable that at least one of [M+C ２ H ５ ] ＋is particularly preferred. In this case, the PAHs is preferably chrysene, which generates fragment ions having a mass number of 215 in step 3 after step 2-1 and can be detected separately from triphenylene. Also preferred as PAHs are benzo[b]fluoranthene, which generates fragment ions having a mass number of 266 in step 3 after step 2-1, benzo[k]fluoranthene, which generates fragment ions having a mass number of 225, and benzo[j]fluoranthene, which generates fragment ions having a mass number of 253.

[0017] In step 3, fragment ions derived from the precursor ion are generated. In step 3 after step 2-1, in the above-mentioned case, if the PAHs is chrysene, a fragment ion having a mass number of 215 is generated, if the PAHs is benzo[b]fluoranthene, a fragment ion having a mass number of 266 is generated, if the PAHs is benzo[k]fluoranthene, a fragment ion having a mass number of 225 is generated, and if the PAHs is benzo[j]fluoranthene, a fragment ion having a mass number of 253 is generated.

[0018] In step 4, the presence or absence of PAHs is detected based on the presence or absence of fragment ions. Here, the PAHs may be chrysene and triphenylene, and the presence or absence of chrysene or triphenylene may be detected based on the presence or absence of fragment ions in step 4. In this case, if fragment ions are present in step 4, it may be determined that at least chrysene is present, or if fragment ions are not present, it may be determined that at least chrysene is not present.

[0019] [2] SMCI-MS / MS Method with Acetonitrile Incorporation Figure 2 shows the results of an analysis of a mixed standard of chrysene (10 ppm) and triphenylene (10 ppm) using SMCI-MS / MS with acetonitrile incorporation. Thus, using SMCI-MS / MS with acetonitrile incorporation makes it possible to individually detect chrysene and triphenylene, which was previously difficult. Figure 3 also shows the results of an analysis of a mixed standard of phenanthrene (10 ppm) and anthracene (10 ppm) using SMCI-MS / MS with acetonitrile incorporation. Using SMCI-MS / MS with acetonitrile incorporation makes it possible to individually detect chrysene and triphenylene, which was previously difficult even with CI-MS / MS with methane gas incorporation. The SMCI-MS / MS method using acetonitrile is itself a known technique, and examples thereof include Collen 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 Document 5), and Xiang Zhang, "Gas-phase cleavage of the novel iminium ions [R1-CH + -N=CH-R2←→R1-CH=N + Based on known literature such as "=CH-R2: An experimental and computational study", Journal of Molecular Structure 1056-1057 (2014) 219-226 (Non-Patent Document 6), a commercially available product (e.g., GCMS-TQ （商標）The process can be carried out under appropriate conditions using a 8050 NX (manufactured by Shimadzu Corporation). 2 and 3 show the results of an SMCI-MS / MS method in which acetonitrile was introduced under the following conditions: vaporization chamber temperature: 275°C; carrier gas control: column flow rate (1.00 mL / min); column: Rxi-PAH (60.0 m x 0.25 mm I.D. x 0.10 μm); column temperature: 110°C (1 min) → (30°C / min) → 210°C → (3°C / min → 250°C (6 min) → 350°C (5 min); transfer line temperature: 250°C; ion source temperature: 230°C; collision energy: 10 eV. Note that the above conditions are merely an example, and the present invention is not limited to these. Similar results are obtained when an SMCI-MS / MS method in which acetonitrile is introduced is performed under the conditions given as an example for the CI-MS / MS method in which methane gas is introduced.

[0020] Step 1 may be carried out in the same manner as described above in Step 1 for the CI-MS / MS method using methane gas. However, in the case of the SMCI-MS / MS method using acetonitrile, suitable examples of PAHs include chrysene, triphenylene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene, as well as phenanthrene and anthracene.

[0021] In step 2-2, acetonitrile was introduced and PAHs were ionized using the SMCI method to obtain [M + CH] ＋ , [M+HNC ２ ] ＋ , [M+H ２ NC ２ ] ＋The SMCI method is an ionization method that uses a solvent instead of a flammable gas, and when acetonitrile is used as the solvent, an ion called MIE is generated in the ion source. MIE has the property of bonding with a double bond by causing a 2+2 cycloaddition reaction. Therefore, it is known that compounds such as olefins that contain double bonds generate MIE adduct ions with a mass number that is 54 greater than the mass number M. It has been found that the method according to the present invention generates not only MIE adduct ions but also special precursor ions other than MIE adduct ions for compounds with a benzene ring. These precursor ions are formed by cleavage of the MIE adduct ions at the bond site, and there are three types ([M+CH] ＋ , [M+HNC ２ ] ＋ , [M+H ２ NC ２ ] ＋ ) is produced. This has been confirmed for the 36 PAHs regulated by EPA 2260a, benzene, toluene, and xylene. Because aromatics have a stable structure, it is thought that the MIE bond, which is less stable than the basic skeleton, causes fragmentation. Furthermore, one of the three types of ions produced is thought to be cleaved by removing a hydrogen from the basic skeleton, so the ease of ion production varies depending on the three-dimensional structure of the basic skeleton. Furthermore, because the stability of the basic skeleton itself changes, the ease of fragment ion production also varies depending on the location where the hydrogen is extracted.

[0022] In step 3, fragment ions derived from the precursor ion are generated. In the case of step 3 after step 2-2, in the above-mentioned case, when the PAHs is chrysene, a fragment ion having a mass number of 215 is generated, when the PAHs is triphenylene, a fragment ion having a mass number of 241 is generated, when the PAHs is benzo[b]fluoranthene, a fragment ion having a mass number of 266 is generated, when the PAHs is benzo[k]fluoranthene, a fragment ion having a mass number of 225 is generated, when the PAHs is benzo[j]fluoranthene, a fragment ion having a mass number of 253 is generated, when the PAHs is phenanthrene, a fragment ion having a mass number of 201 is generated, and when the PAHs is anthracene, a fragment ion having a mass number of 192 is generated.

[0023] In step 4, the presence or absence of PAHs is detected based on the presence or absence of fragment ions. In step 4, which follows step 3 after step 2-2, PAHs can be detected individually based on the mass numbers of the fragment ions.

[0024] The method of the present invention, which includes the CI-MS / MS method using methane gas (1) and the SMCI-MS / MS method using acetonitrile (2), enables the individual detection of certain PAHs, thereby speeding up and streamlining analysis. Figure 4 shows an example of the method of the present invention applied to the analytical method using the J&W Select PAH column described in 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 Document 2). Figure 4 is based on Figure 1 in Non-Patent Document 2, but by applying the method of the present invention, the time required for the two rectangles shown in the figure can be shortened, enabling further speedup. More specifically, of the two squares in Fig. 4, the square on the left side of the paper in Fig. 4 is a temperature increase for separating anthracene and phenanthrene, which can be shortened by applying [2] SMCI-MS / MS method with acetonitrile. The square on the right side of the paper in Fig. 4 is a constant temperature for separating chrysene and triphenylene, which can be shortened by applying either [1] CI-MS / MS method with methane gas introduction or [2] SMCI-MS / MS method with acetonitrile introduction.

[0025] The method of the present invention can reduce the probability of false positives due to misidentification, even when polycyclic aromatic compounds are present in food samples containing complex contaminants. Furthermore, the method of the present invention enables qualitative analysis of aromatic compounds by utilizing the ratio of specific precursor ions derived from aromatic compounds.

[0026] The present invention will be explained in more detail below by way of experimental examples, but the present invention is not limited to these examples.

[0027] Experimental Example 1 A mixed standard of chrysene (10 ppm) and triphenylene (10 ppm), as well as benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene, each adjusted to 10 μg / mL (=10 ppm), were used as analytical samples. （商標） Using an 8050 NX (Shimadzu Corporation), CI-MS / MS was performed by introducing methane gas under the following conditions.

[0028] Vaporization chamber temperature: 275°C Carrier gas control: column flow rate (1.00 mL / min) Column: Rxi-PAH (60.0 m x 0.25 mm I.D. x 0.10 μm) Column temperature: 200°C (1 min) → (10°C / min) → 300°C (10 min) Transfer line temperature: 250°C Ion source temperature: 230°C Collision energy: 10 eV Figure 1 shows the results for a mixed standard of chrysene and triphenylene, and a fragment ion (mass number: 215) was confirmed for chrysene only. 5A and 5B show the results for benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), and benzo[j]fluoranthene (B[j]F), with FIG. 5A showing the relationship 281.0 > 266.0, FIG. 5B showing the relationship 281.0 > 225.0, and FIG. 5C showing the relationship 281.0 > 253.0.

[0029] Experimental Example 2: The analytical samples were a mixed standard of chrysene (10 ppm) and triphenylene (10 ppm), a mixed standard of phenanthrene (10 ppm) and anthracene (ppm), and benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene, each adjusted to 10 μg / mL (=10 ppm). （商標） Using an 8050 NX (Shimadzu Corporation), SMCI-MS / MS was performed using acetonitrile under the following conditions.

[0030] Vaporization chamber temperature: 275°C Carrier gas control: column flow rate (1.00 mL / min) Column: Rxi-PAH (60.0 m x 0.25 mm I.D. x 0.10 μm) Column temperature: 110°C (1 min) → (30°C / min) → 210°C → (3°C / min → 250°C (6 min) → 350°C (5 min) Transfer line temperature: 250°C Ion source temperature: 230°C Collision energy: 10 eV FIG. 2 shows the results for a mixed standard of chrysene and triphenylene, where a fragment ion (mass number: 227) was confirmed for chrysene and a fragment ion (mass number: 226) for triphenylene. FIG. 3 shows the results for a mixed standard of phenanthrene and anthracene, where a fragment ion (mass number: 201) was confirmed for phenanthrene and a fragment ion (mass number: 192) was confirmed for anthracene. FIG. 6 shows the results for benzo[b]fluoranthene (B[b]F), benzo[k]fluoranthene (B[k]F), and benzo[j]fluoranthene (B[j]F), where FIG. 6(a) shows the relationship 288.0 > 276.0, FIG. 6(b) shows the relationship 288.0 > 265.0, and FIG. 6(c) shows the relationship 306.0 > 289.0.

[0031] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0032] (Item 1) A method for detecting the presence or absence of a predetermined polycyclic aromatic hydrocarbon (molecular formula: M) according to one embodiment includes a step 1 of chromatographically separating a sample containing the polycyclic aromatic hydrocarbon; and a step 2 of introducing methane gas and ionizing the polycyclic aromatic hydrocarbon using a chemical ionization method to obtain [M+CH ３ ] ＋ , [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ or, by introducing acetonitrile and ionizing the polycyclic aromatic hydrocarbon using solvent-mediated chemical ionization, [M+CH] ＋ , [M+HNC２ ] ＋ , [M+H ２ NC ２ ] ＋ as precursor ions; step 3 generating fragment ions derived from the precursor ions; and step 4 detecting the presence or absence of the polycyclic aromatic hydrocarbons based on the presence or absence of the fragment ions.

[0033] The method described in Section 1 enables individual detection of some PAHs, speeding up analysis and, in particular, shortening the heating time required to separate chrysene and triphenylene. Furthermore, it reduces the probability of false positives due to misidentification, even for polycyclic aromatic compounds in food samples with complex contaminants. Furthermore, qualitative analysis of aromatic compounds becomes possible by applying the ratio of special precursor ions derived from aromatic compounds.

[0034] (Item 2) In the method according to item 1, the precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ At least one of the above.

[0035] According to the method described in Section 2, characteristic fragment ions are generated, and chrysene and triphenylene can be detected individually.

[0036] (Item 3) In the method according to item 1, the polycyclic aromatic hydrocarbon is chrysene.

[0037] According to the method of item 3, chrysene can be detected individually. (Item 4) In the method of item 3, the precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ is.

[0038] According to the method described in Section 4, characteristic fragment ions are generated, and chrysene and triphenylene can be detected individually.

[0039] (Item 5) According to the method of item 3 or 4, the fragment ions generated in step 3 after step 2-1 have a mass number of 215.

[0040] According to the method described in Section 5, the fragment ion with a mass number of 215 is confirmed to be chrysene alone, and chrysene can be detected individually.

[0041] (Item 6) In the method according to item 1, the polycyclic aromatic hydrocarbons are chrysene and triphenylene, and in step 4 after steps 2-1 and 3, the presence or absence of chrysene or triphenylene is detected based on the presence or absence of fragment ions.

[0042] According to the method described in item 6, chrysene and triphenylene can be detected separately, and the analysis can be performed at a high speed.

[0043] (Item 7) In the method according to item 6, if fragment ions are present in step 4 after step 2-1 and step 3, it is determined that at least chrysene is present.

[0044] According to the method described in item 7, the temperature-raising time required for separating chrysene and triphenylene can be shortened.

[0045] (Item 8) In the method according to item 6, if no fragment ions are present in step 4 after step 2-1 and step 3, it is determined that at least chrysene is not present.

[0046] According to the method described in item 8, the temperature-raising time required for separating chrysene and triphenylene can be shortened.

[0047] (Item 9) In the method according to item 1, the polycyclic aromatic hydrocarbon is benzo[b]fluoranthene, benzo[k]fluoranthene, or benzo[j]fluoranthene.

[0048] According to the method described in item 9, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene can also be detected individually.

[0049] (Item 10) In the method according to item 9, the precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ is.

[0050] According to the method described in item 10, characteristic fragment ions are generated, and benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene can be detected individually.

[0051] (Item 11) In the method according to item 10, the fragment ions generated in step 3 after step 2-1 have mass numbers of 266 for benzo[b]fluoranthene, 225 for benzo[k]fluoranthene, and 253 for benzo[j]fluoranthene.

[0052] According to the method described in item 11, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[j]fluoranthene can be detected individually.

[0053] (Item 12) In the method according to item 1, the polycyclic aromatic hydrocarbons are phenanthrene and anthracene, and in step 4 after step 2-2 and step 3, the presence or absence of phenanthrene or anthracene is detected based on the presence or absence of fragment ions.

[0054] According to the method described in item 12, when SMCI containing acetonitrile is used, phenanthrene and anthracene can also be separated, which makes it possible to further improve the efficiency of analysis.

Claims

1. A method for detecting the presence or absence of a predetermined polycyclic aromatic hydrocarbon (molecular formula: M), comprising the steps of: chromatographically separating a sample containing the polycyclic aromatic hydrocarbon; and ionizing the polycyclic aromatic hydrocarbon by introducing methane gas and using a chemical ionization method to obtain [M+CH ３ ] ＋ , [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ or, by introducing acetonitrile and ionizing the polycyclic aromatic hydrocarbon using a solvent-mediated chemical ionization method, [M+CH] ＋ , [M+HNC ２ ] ＋ , [M+H ２ N.C. ２ ] ＋ a step 2-2 of generating at least one of the above as a precursor ion; a step 3 of generating fragment ions derived from the precursor ion; and a step 4 of detecting the presence or absence of the polycyclic aromatic hydrocarbons based on the presence or absence of the fragment ions.

2. The precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ , [M+C ３ H ５ ] ＋ The method according to claim 1, characterized in that it is at least one of the following:

3. The method of claim 1, wherein the polycyclic aromatic hydrocarbon is chrysene.

4. The precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ The method according to claim 3, characterized in that 5. The method according to claim 3 or 4, characterized in that the fragment ion generated in step 3 after step 2-1 has a mass number of 215.

6. The method according to claim 1, wherein the polycyclic aromatic hydrocarbons are chrysene and triphenylene, and in step 4 following step 2-1 and step 3, the presence or absence of chrysene or triphenylene is detected based on the presence or absence of fragment ions.

7. The method according to claim 6, wherein in step 4 after step 2-1 and step 3, if a fragment ion is present, it is determined that at least chrysene is present.

8. The method according to claim 6, wherein if no fragment ions are present in step 4 after step 2-1 and step 3, it is determined that at least chrysene is not present.

9. The method of claim 1, wherein the polycyclic aromatic hydrocarbon is benzo[b]fluoranthene, benzo[k]fluoranthene, or benzo[j]fluoranthene.

10. The precursor ion generated in step 2-1 is [M+C ２ H ５ ] ＋ 10. The method according to claim 9, wherein 11. The method according to claim 10, wherein the fragment ions generated in step 3 after step 2-1 have mass numbers of 266 for benzo[b]fluoranthene, 225 for benzo[k]fluoranthene, and 253 for benzo[j]fluoranthene.

12. The method according to claim 1, wherein the polycyclic aromatic hydrocarbons are phenanthrene and anthracene, and in step 4 following step 2-2 and step 3, the presence or absence of phenanthrene or anthracene is detected based on the presence or absence of fragment ions.

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