Method and device for analyzing organic fluorine compound

Abstract

The present invention relates to an analysis device for analyzing PFAS in a sample, the analysis device comprising: a storage unit (226) for storing calibration information created using peak information observed in an EIC at m / z of fragment ions derived from fluorocarbon as a pyrolysis product and observed in common in PFAS, the EIC being created on the basis of data collected by performing Py-GC / MS on one standard sample having a predetermined concentration or a plurality of standard samples having different concentrations with regard to PFAS having a carbon chain in which the number of carbon atoms corresponds to a predetermined value; a measurement unit (1) that is a Py-GC / MS device; a chromatogram creation unit (222) that creates an EIC at the m / z on the basis of data collected by measurement by the measurement unit with respect to an unknown sample of PFAS having a carbon chain in which the number of carbon atoms corresponds to a value other than the predetermined value; and quantification units (223, 225) that obtain a quantitative value by comparing peak information observed in the EIC with calibration information stored in the storage unit.

Description

Method and apparatus for analyzing organic fluorine compounds

[0001] The present invention relates to a method and an apparatus for analyzing organic fluorine compounds, particularly organic fluorine compounds called PFAS (Per and poly FluoroAlkyl Substances). Although there are various definitions of PFAS, for example, in a publication by the Organization for Economic Cooperation and Development (OECD) in 2021, it is defined as a chemical substance having at least a perfluoromethyl group (-CF3) or a perfluoromethylene group (-CF2).

[0002] When quantifying the compounds contained in a sample using a gas chromatograph device or a gas chromatograph mass spectrometer, it is common to find the peak corresponding to the target compound in the chromatogram created based on the data collected by the analysis, and calculate the concentration by comparing the area of the peak with a calibration curve. The calibration curve used for such quantification is usually created in advance based on the results of analyzing a standard sample containing the target compound with a known concentration.

[0003] In recent years, some compounds belonging to PFAS have been pointed out to be harmful to humans and organisms, and moreover, due to their high persistence and bioaccumulation, the movement to prohibit or regulate their use and production has been spreading in various countries. Currently, the PFAS prohibited by the "Stockholm Convention on Persistent Organic Pollutants" (so-called POPs (Persistent Organic Pollutants) Convention) are perfluorooctanoic acid (PFOA), which is a perfluorocarboxylic acid (PFCA) with a carbon chain of 6, perfluorohexanesulfonic acid (PFHxS), which is a perfluorosulfonic acid (PFSA) with carbon chains of 6 and 8, and perfluorooctanesulfonic acid (PFOS). However, in the future, it is being considered to prohibit compounds with longer carbon chains as well.

[0004] The common analytical method for PFAS involved a combination of solvent extraction and liquid chromatography-tandem mass spectrometry (for example, the test method in the European Committee for Standardization (CEN) standard "EN 17681-1:2022"), but this method had the drawback of requiring quite complicated sample preparation, which was time-consuming and costly.

[0005] Lisa Skedung and 5 others, “Identification and quantification of fluorinated polymers in consumer products by combustion ion chromatography and pyrolysis-gas chromatography-mass spectrometry”, Environmental Science: Processes & Impacts, 2024, Vol. 26, pp. 82-93

[0006] Recently, attempts to analyze PFAS using pyrolysis gas chromatography-mass spectrometry (Py-GC / MS) have been reported (Non-Patent Literature 1). When resins containing PFCA and PFSA are analyzed using a Py-GC / MS instrument, the PFCA and PFSA in the resin are instantly and completely vaporized in the pyrolysis furnace, producing carbon fluoride from which the carboxyl and sulfone groups have been removed. Based on the presence or absence of fragment ion peaks with a mass-to-charge ratio (m / z) specific to this carbon fluoride and the pattern of the mass spectrum, it is possible to estimate whether or not PFCA and PFSA are present. However, although the method reported in Non-Patent Literature 1 confirms the presence of PFAS such as PFCA and PFSA, it has not been possible to identify the types of compounds belonging to PFCA and PFSA or to determine their concentrations.

[0007] In response to this, the inventors have found that by appropriately determining the GC separation conditions in Py-GC, multiple compounds with different numbers of carbon atoms contained in PFCA can be separated with considerable success. If separation by gas chromatography is possible, it is expected that PFCA can be identified and quantified using the retention time or retention index of the peaks observed in the chromatogram. However, such quantification methods have the following problems.

[0008] To quantify various PFCAs with different carbon chain lengths using peak areas on chromatograms, it is necessary to create a calibration curve beforehand using standard samples of each PFCA. However, PFCAs are generally synthesized using a method called telomerization, which, in principle, cannot produce PFCAs with odd-numbered carbon chains. Although it is possible to produce them by other methods, the standard samples produced in this way are practically unavailable. Furthermore, even for PFCAs with even-numbered carbon chains, the longer the carbon chain, the more complicated the manufacturing process becomes, making them expensive and difficult to obtain. The situation is similar, to varying degrees, for other PFASs such as PFSAs.

[0009] This invention has been made in view of these problems, and its main objective is to provide an analytical method and apparatus for organofluorine compounds that can quantify various types of PFAS without using hard-to-obtain standard samples of PFAS.

[0010] One aspect of the method for analyzing organofluorine compounds according to the present invention is an analytical method for analyzing PFAS in a sample, comprising: a measurement step of performing pyrolysis gas chromatography-mass spectrometry on one or a plurality of standard samples of PFAS having a carbon chain with a predetermined number of carbon atoms, at a predetermined concentration, and collecting data; a calibration information acquisition step of creating an extracted ion chromatogram for each of the one or a plurality of standard samples of the predetermined concentration, based on the data obtained in the measurement step, at the mass-to-charge ratio of fragment ions derived from fluorinated carbon, which is a pyrolysis product, and commonly observed in PFAS, and obtaining calibration information using the peak information on the extracted ion chromatogram; an unknown sample measurement step of performing pyrolysis gas chromatography-mass spectrometry on an unknown sample of PFAS whose carbon chain has a predetermined number of carbon atoms or a value other than the predetermined number, and collecting data; and a chromatogram creation step of creating an extracted ion chromatogram of the unknown sample at the mass-to-charge ratio based on the data obtained in the unknown sample measurement step. The method includes a quantitative step of determining the quantitative value of PFAS in the unknown sample using the peak information on the ion chromatogram extracted from the unknown sample and the calibration information.

[0011] Furthermore, one embodiment of the organofluorine compound analyzer according to the present invention is an analyzer for analyzing PFAS in a sample, comprising: a storage unit that stores calibration information obtained using peak information observed in an extracted ion chromatogram of the mass-to-charge ratio of fragment ions derived from fluorinated carbon, which is a pyrolysis product, and commonly observed in PFAS, which is created based on data collected by performing pyrolysis gas chromatography-mass spectrometry on one or a plurality of standard samples of predetermined concentrations of PFAS having a carbon chain with a predetermined number of carbons; a measurement unit which is a pyrolysis gas chromatography-mass analyzer; a chromatogram creation unit that creates an extracted ion chromatogram of an unknown sample at the mass-to-charge ratio based on data collected by measurement by the measurement unit on an unknown sample of PFAS whose carbon chain has the predetermined number of carbons or a value other than the predetermined number; and a quantitative unit that determines the quantitative value of PFAS in the unknown sample using the peak information observed in the extracted ion chromatogram of the unknown sample and the calibration information stored in the storage unit.

[0012] According to the above-described embodiment of the method and apparatus for analyzing organofluorine compounds of the present invention, for example, calibration information obtained by analyzing a standard sample of a specific PFCA that is readily available is used to quantify a PFCA of a different type (with a different number of carbon atoms in its carbon chain). Furthermore, the same calibration information is used to quantify another compound that is not a PFCA, for example, a compound belonging to PFSA. In other words, the same calibration information is used to quantify various PFASs, including PFCAs and PFSAs. This eliminates the need for the cumbersome process of preparing a standard sample for each PFCA to be quantified, performing analysis on those standard samples, and creating a calibration curve, thereby reducing the effort and cost required to quantify PFASs in a sample. In addition, it becomes possible to quantify PFASs of types for which standard samples are generally difficult or practically impossible to obtain, making it easier to determine the concentrations of various PFASs contained in products or present in the environment.

[0013] A diagram illustrating the overall configuration of a PFAS analyzer, which is one embodiment of the present invention. A schematic diagram illustrating the method for identifying and quantifying PFCA in the PFAS analyzer of this embodiment. A flowchart showing the procedure for obtaining retention time and retention index included in compound information in the PFAS analyzer of this embodiment. A flowchart showing the procedure for obtaining calibration curve included in compound information in the PFAS analyzer of this embodiment. A diagram showing an example of the analytical conditions for identifying and quantifying PFCA in the PFAS analyzer of this embodiment. A diagram showing an example of measured EIC (m / z 69) of various PFCAs (C3-C14, C16, C18) obtained by a Py-GC / MS instrument under the analytical conditions shown in Figure 5. A diagram showing an example of measured EIC (m / z 131) of various PFCAs (C3-C14, C16, C18) obtained by a Py-GC / MS instrument under the analytical conditions shown in Figure 5. A diagram showing an example of the analytical conditions for a Py-GC / MS instrument when using a normal column. Figure 8 shows examples of measured EIC (m / z 69) for various PFCAs (C3-C14, C16, C18) obtained by a Py-GC / MS instrument under the analytical conditions shown in Figure 8. Figure 9 shows examples of measured EIC (m / z 131) for various PFCAs (C3-C14, C16, C18) obtained by a Py-GC / MS instrument under the analytical conditions shown in Figure 8. Figure 10 shows examples of measured EIC (m / z 69) for PFHxS, PFHxS + NaOH, and PFHpA obtained by a Py-GC / MS instrument. Figure 10 shows an example of carbon fluoride produced by the thermal decomposition of PFCA. Figure 20 shows an example of carbon fluoride produced by the thermal decomposition of PFSA with added NaOH. Figure 30 shows an example of a calibration curve for PFCAs with different carbon numbers.

[0014] [Supplementary explanation of the above embodiment] In the above embodiment, the pyrolysis gas chromatograph mass spectrometer may be equipped with an ionization unit using, for example, electron ionization, chemical ionization, negative chemical ionization, or low-voltage electron ionization. Furthermore, the mass separator is not limited to a specific type or embodiment, and for example, quadrupole type, Fourier transform type, ion trap type, magnetic field type, time-of-flight type, hybrid type, etc. may be used. In addition, MS / MS analysis such as triple quadrupole type, or MS nThe system may also be capable of performing analysis (where n is an integer greater than or equal to 3). Furthermore, the mass spectrometer may combine mass spectrometry with ion mobility analysis.

[0015] Furthermore, the "calibration information" mentioned above shall include a calibration curve showing the relationship between concentration and peak area value or sensitivity coefficient (= peak area value / mass), or a relative sensitivity coefficient with respect to a reference substance.

[0016] [Configuration of a PFAS analyzer according to one embodiment] Hereinafter, a PFAS analyzer according to one embodiment of the present invention and a method for identifying and quantifying PFAS using this apparatus will be described with reference to the attached drawings. Figure 1 is a schematic configuration diagram of the PFAS analyzer according to this embodiment. As shown in Figure 1, this PFAS analyzer uses a pyrolysis gas chromatograph mass spectrometer (hereinafter referred to as "Py-GC / MS apparatus") and includes a measurement unit 1 and a control / processing unit 2.

[0017] The measurement unit 1 consists of a Py-GC unit 11 and an MS unit 12. The Py-GC unit 11 includes a column oven 114, a column 115 housed in the column oven 114, a sample introduction unit 112 provided at the inlet end of the column 115, a pyrolysis unit 111 attached upstream of the sample introduction unit 112, and a carrier gas flow path 113 that supplies carrier gas to the column 115 through the pyrolysis unit 111 and the sample introduction unit 112.

[0018] The MS unit 12 includes a vacuum chamber 121 and an ionization unit 122, an ion lens 123, a quadrupole mass filter 124, and a detector 125, all of which are disposed inside the vacuum chamber 121. For example, the ionization unit 122 ionizes components contained in the gas exiting from the outlet end of the column 115 by electron ionization (EI), but it is also possible to use ionization methods other than EI, such as chemical ionization. Furthermore, the mass separator is not limited to a quadrupole mass filter, but can be any type or configuration that is appropriate, such as a triple quadrupole type, Fourier transform type, ion trap type, magnetic field type, time-of-flight type, or hybrid type.

[0019] As an example of a specific apparatus, the pyrolysis section 111 of the Py-GC section 11 uses the multi-shot pyrolizer "EGA / PY3030D" manufactured by Frontier Labs Co., Ltd., and the GC section and MS section 12 of the Py-GC section 11 use the gas chromatograph mass spectrometer "GCMS-QP" manufactured by Shimadzu Corporation. TM It may be decided to use "2020 NX".

[0020] The control and processing unit 2 includes an analysis control unit 21 and a data processing unit 22. The analysis control unit 21 includes an analysis condition storage unit 211 that stores various analysis conditions. The data processing unit 22 includes, as functional blocks, a data storage unit 221, a chromatogram creation unit 222, a peak detection unit 223, an identification unit 224, a quantification unit 225, and a compound information storage unit 226. Generally, the control and processing unit 2 is configured around a computer such as a personal computer, and the functions of each of the above functional blocks can be realized by executing predetermined software (computer programs) installed on the computer. In addition, an input unit 3 and a display unit 4 are connected to the control and processing unit 2 as a user interface.

[0021] To perform PFAS analysis, an analysis method for PFAS analysis is installed in the computer that constitutes the control and processing unit 2. This analysis method is a type of software and includes various information on analysis conditions stored in the analysis condition storage unit 211 and a compound table 227, as shown in Figure 1, stored in the compound information storage unit 226.

[0022] [Identification and Quantification Method for PFCA] An overview of the identification and quantification method for PFCA in the PFAS analyzer of this embodiment will be explained with reference to Figure 2. As previously mentioned, although attempts have been made to measure PFAS using a Py-GC / MS instrument, the identification of various compounds belonging to PFCA has not been achieved. In response to this, the inventors have repeatedly conducted experiments on the analysis of PFCA using a Py-GC / MS instrument and have obtained a new finding that carbon fluoride, which is a thermal decomposition product obtained by thermal decomposition of PFCA, reflects the structure of the original PFCA (such as the length of the carbon chain). For example, as shown in Figure 10, in the case of PFOA, a type of PFCA, perfluoro-1-heptene (CAS number 355-63-5), a type of carbon fluoride, is specifically produced by the removal of a carboxyl group and one fluorine atom through thermal decomposition. In other words, in the thermal decomposition products of PFCA, the length (number of carbon atoms) of the carbon chain after the carboxyl group is removed is maintained.

[0023] Therefore, by appropriately setting the GC separation conditions, such as using a PLOT column specifically designed for low-molecular-weight gas analysis, it is possible to temporally separate different carbon fluorides in GC, each reflecting the structure of the original PFCA, specifically the number of carbon atoms. As a result, as shown in Figure 2, different carbon fluorides are generated from each PFCA with a different number of carbon atoms by thermal decomposition, and these carbon fluorides can be separated in GC.

[0024] When ionization is performed using the ionization (EI) method in a mass spectrometer, fragmentation occurs vigorously. In fragmentation, weaker molecular bonds are preferentially cleaved, so common fragment ions with relatively strong bonds are easily generated from various carbon fluorides with different structures. Therefore, fragment ions with high intensity, such as m / z 69 (CF3 ion) and m / z 131 (C3F5 ion), are easily observed. For example, if a selected ion monitoring (SIM) measurement targeting the m / z of these fragment ions is performed in a mass spectrometer, or if only the m / z data corresponding to the fragment ions is selected from the results of a scan measurement, and an extracted ion chromatogram (EIC) is created, peaks originating from carbon fluorides corresponding to each type of PFCA may be observed in the EIC.

[0025] Figure 6 shows an example of measured EIC at m / z 69 for PFCA (C3-C14, C16, C18). Figure 7 shows an example of measured EIC at m / z 131 for PFCA (C3-C14, C16, C18). The analytical conditions of the Py-GC / MS instrument at this time are shown in Figure 5. A characteristic feature of these analytical conditions is that a plot column, often used in gas analysis such as petrochemicals, is used as the column, rather than a general-purpose column.

[0026] For comparison, Figures 9 and 10 show the results of measuring the EIC at m / z 69 and m / z 131 for PFCA (C3-C14, C16, C18) under the analytical conditions of a Py-GC / MS instrument using a general-purpose column, as shown in Figure 8.

[0027] As can be seen from Figures 9 and 10, under the analytical conditions shown in Figure 8, the peaks of fluorinated carbons with a small number of carbon atoms in the carbon chain (e.g., C9 or less) are not sufficiently separated at both m / z 69 and m / z 131, making it difficult to identify these fluorinated carbons. In contrast, under the analytical conditions shown in Figure 5, as can be seen from Figures 6 and 7, many of the peaks corresponding to fluorinated carbons derived from PFCA are sufficiently separated at both m / z 69 and m / z 131. In particular, fluorinated carbons derived from PFCAs with a small number of carbon atoms in the carbon chain, which were not separated at m / z 69 and m / z 131 with the general-purpose column, are clearly separated, making it possible to identify these fluorinated carbons. Although some PFCAs may appear with peaks separated before and after the peak, and some of these peaks may overlap, it is clear from Figures 6 and 7 that each PFCA can be sufficiently identified using a combination of multiple peaks.

[0028] From these findings, it can be seen that by analyzing with a Py-GC / MS instrument under appropriate analytical conditions, such as using a plot column, a wide range of PFCAs, including those with a small number of carbon atoms in the carbon chain (approximately C9 or less) that are practically indistinguishable by conventional methods, can be identified based on the retention time of the peak observed in EIC or the retention index derived from the retention time. In other words, PFCAs can be identified using this retention time or retention index.

[0029] Furthermore, since the peak area observed in EIC reflects the original amount of PFCA, the concentration of a specific PFCA can also be determined using the peak area value. Specifically, by creating a calibration curve in advance based on the response factor (RF) obtained by dividing the peak area by the mass for each PFCA, the quantitative value (concentration) can be determined for a specific type of PFCA by comparing the sensitivity factor calculated from the peak area value with the calibration curve. The reason why the peak area value is not used directly as the calibration curve is that, unlike conventional GC / MS instruments, the analyte in a Py-GC / MS instrument may be a solid, and in that case, the peak area value needs to be corrected by the weight of the solid.

[0030] Although Figures 6 and 7 only show the results for PFCAs with 18 carbon atoms or less, it is clear that by selecting an appropriate m / z, PFCAs with 19 carbon atoms or more can also be sufficiently detected. Therefore, the analytical method shown here is not applicable only to PFCAs with 18 carbon atoms or less, but can also be applied to PFCAs with more carbon atoms. Of course, it is not always necessary to detect PFCAs with such a wide range of carbon atoms, and it is clear that the analytical method of this embodiment can be used to detect PFCAs within a specific range of carbon atoms, for example, by limiting the detection to only PFCAs with short carbon chains of about 10 carbon atoms or less, as needed.

[0031] [Identification and Quantification Method for PFSA] Next, we will briefly explain the identification and quantification method for PFSA. According to the inventors' experimental studies, unlike PFCA, the carbon fluoride obtained by thermal decomposition of PFSA does not reflect the structure of the original PFSA. This is thought to be because the strength of the carbon chain bonds differs due to the differences in functional groups. Therefore, even if GC separation conditions are devised, such as by using a plot column, it is not possible to detect carbon fluoride that correlates with the structure of PFSA, or even if it is detected, the sensitivity is extremely low and impractical.

[0032] Therefore, the inventors investigated various pretreatments that affect the sulfo group contained in PFSA, and as a result, they found that when a basic solution such as a sodium hydroxide (NaOH) solution is added to PFSA or a resin containing PFSA and then thermally decomposed, carbon fluoride reflecting the structure of the original PFSA is produced as a thermal decomposition product. For example, as shown in Figure 13, when 5 μL of a 1N concentration NaOH aqueous solution is added to PFOS (number of carbon atoms: 8), a type of PFSA, and thermally decomposed, a sulfo group and one fluorine atom are removed, producing perfluoro-1-octene (CAS number 559-14-8), a type of carbon fluoride.

[0033] Figure 11 shows examples of measured EICs at m / z 69 when perfluorohexanesulfonic acid (PFHxS, C6) is analyzed directly using a Py-GC / MS instrument, and when PFHxS is analyzed with NaOH added. For reference, Figure 11 also shows the EIC when perfluoroheptanoic acid (PFHpA), a type of PFCA, is analyzed using a Py-GC / MS instrument. As can be seen from the EICs shown in Figure 11, the addition of NaOH causes PFHxS to exhibit a peak at the same retention time as PFHpA. Therefore, as with the PFCA case described above, it is possible to identify the type of PFSA based on the retention time of the peak on the EIC by adjusting the GC separation conditions. Furthermore, it is possible to calculate the concentration of the identified PFSA using the area of ​​the peak on the EIC, specifically, by using a calibration curve of the sensitivity coefficient.

[0034] [Operation of Identification and Quantitative Analysis] Next, an example of the operation when identifying and quantifying PFCA and / or PFSA using the PFAS analyzer shown in Figure 1 by the method described above will be explained. The analytical conditions stored in the analytical condition storage unit 211 include information such as the type of column to be used (or recommended to be used), in addition to numerical parameters such as gas flow rate. The user prepares the system according to these analytical conditions. Meanwhile, the compound information storage unit 226 stores a compound table 227 as a kind of database for identification and quantification, which contains information such as molecular weight, m / z values ​​of quantitative ions and confirmatory ions, retention time, retention index, and calibration curve for various compounds belonging to PFCA.

[0035] Here, we will explain how to obtain retention time and retention index data to be registered in compound table 227, referring to Figure 3. Figure 3 is a flowchart showing an example of the procedure for obtaining retention time and retention index data. Generally, when creating a calibration curve to quantify a compound, it is necessary to measure a standard sample of that compound. In addition, information on retention time and retention index data for identifying the compound can also be collected by measuring a standard sample of that compound. However, due to the following circumstances, obtaining standard samples is not always easy in PFCA.

[0036] Currently, PFCA is generally synthesized using a method called telomerization, but in principle, this method cannot synthesize PFCA with an odd number of carbon atoms in the carbon chain. Furthermore, even if the number of carbon atoms is even, the manufacturing process becomes complicated as the carbon chain length increases, making it difficult to produce, and the standard samples are expensive. For these reasons, it is desirable to obtain accurate retention time, retention index, and calibration information while minimizing the number of standard samples used. In response to this, the PFAS analyzer of this embodiment estimates the retention time (and retention index) of other types of PFCA and PFSA using the analysis results of a specific PFCA standard sample, and registers them in the compound table 227.

[0037] The specific procedure involves, first, the operator preparing two or more standard samples of PFCA with different numbers of carbon atoms in their carbon chains (Step S1). Then, each of these two types of PFCA is analyzed using a Py-GC / MS instrument under the same analytical conditions, such as the column temperature profile (Step S2). For example, when a user performs this operation, they should carry out the measurement according to the analytical conditions provided by the instrument manufacturer or the like.

[0038] Specifically, in step S2, the MS unit 12 performs a SIM measurement, for example, using m / z 131 as the quantitative ion and m / z 69 as the confirmation ion. Then, the chromatogram creation unit 222 uses the data obtained from the measurement to create an EIC at m / z 131, which is the quantitative ion (step S3). The peak detection unit 223 detects the peak originating from the standard sample in the EIC and determines the retention time from the position of that peak (step S4). After obtaining the retention times of two or more different types of PFCA, the identification unit 224 finds an approximate formula as a relational expression showing the relationship between the number of carbon atoms in PFCA and the retention time (step S5).

[0039] According to the inventors' experiments, when PFCA is analyzed using a nonpolar or slightly polar stationary phase column and GC separation conditions such as column heating rate and column flow rate (or linear velocity) are kept constant, it was found that the retention time of each peak corresponding to PFCA is proportional to the length of the carbon chain (i.e., the number of carbon atoms). In other words, the retention times of PFCA are approximately equally spaced. Based on this regularity, the above approximation formula can be obtained as a linear equation such as RT = aC + b (where RT: retention time, C: number of carbon atoms in PFCA). Of course, the approximation formula does not necessarily have to be a linear equation; it may be a polynomial of degree two or higher.

[0040] After obtaining an approximate formula, the identification unit 224 substitutes the number of carbon atoms of PFCAs for which standard samples are not available into the approximate formula and estimates the retention time corresponding to that PFCA (step S6). Furthermore, under the same GC separation conditions such as the column temperature profile, GC / MS analysis is performed on the n-alkane, which is the standard for the retention index, and the retention index for each PFCA is calculated from the retention time obtained from the analysis (step S7). In this way, the retention time and retention index are determined not only for PFCAs for which standard samples were available but also for PFCAs for which standard samples are not available, and these are registered in the compound table 227 prepared in the compound information storage unit 226 (step S8). By using the compound table 227 in which the retention time and retention index have been registered according to this procedure, it becomes possible to identify PFCAs that are unavailable or difficult to obtain.

[0041] Next, a method for creating a calibration curve registered in the compound table 227 will be described. FIG. 4 is a flowchart showing an example of the procedure for creating a calibration curve. Generally, a calibration curve is created based on the results obtained by analyzing samples of two or more known concentrations prepared by diluting a standard sample containing the target compound. However, in the case of PFCA, as described above, the available PFCA for standard samples is limited. In contrast, as a result of various experiments, the present inventor has found that even for PFCA with different carbon chain lengths, the slopes of the calibration curves created using the peak area values observed in the EIC of a specific m / z, for example m / z 131, are almost the same.

[0042] FIG. 14 is a diagram showing calibration curves of four types of PFCA with carbon numbers of 4, 8, 12, and 16 created based on the peak area values observed in the EIC of m / z 131. As can be seen from FIG. 14, PFCA with a carbon number of 4 shows a different tendency from PFCA with carbon numbers of 8, 12, and 16. In the case of C4 PFCA, since the carbon chain is too short, the influence of the terminal is large, and it can be推测 that it is difficult to generate C3F5 + ions. On the other hand, for PFCA with a carbon number of a certain degree or more, it can be seen that all the calibration curves can be regarded as straight lines and their slopes are quite close. This means that for a carbon number of a certain degree or more, even if the calibration curve created for a specific PFCA is applied to a different PFCA, a reasonable quantitative value can be obtained. That is, it is possible to perform quantification using a common calibration curve for a plurality of different types of PFCA. Therefore, in the PFAS analyzer of the present embodiment, the calibration curve obtained from a standard sample of PFCA that is relatively easy to obtain is also used as the calibration curve for other PFCA.

[0043] As a specific procedure for creating a calibration curve, first, the operator prepares samples of multiple concentrations from the obtained standard sample of PFCA (step S11). The standard sample used here preferably has a carbon number of 6 or more, but PFCA with a carbon number less than 6 can also be used depending on the allowable value of the quantification accuracy.

[0044] The measurement unit 1 performs analysis on samples of multiple concentrations using a Py-GC / MS apparatus under predetermined analysis conditions respectively (step S12). Specifically, in the MS unit 12, SIM measurement is performed with predetermined m / z values (for example, m / z 131, m / z 69, etc.) as quantitative ions and confirmation ions. Then, the chromatogram creation unit 222 creates an EIC at, for example, m / z 131 which is the quantitative ion, using the data obtained from the measurement (step S13). The peak detection unit 223 detects the peak derived from the standard sample in the EIC and obtains the area value of the peak (step S14). The confirmation ions are used to confirm whether the peak detected in the EIC of the quantitative ion is derived from PFCA.

[0045] After the peak area values for samples with different concentrations are obtained in this way, the quantification unit 225 calculates the sensitivity coefficient from the peak area value using the mass of the known sample (step S15). Then, a calibration curve showing the relationship between the concentration and the sensitivity coefficient is created (step S16). Thus, the calibration curve obtained for PFCA for which the standard sample was available is registered in the compound table 227 so that it can be used not only as the calibration curve for that PFCA but also as the calibration curve for other PFCA (step S17).

[0046] Note that one of the samples of multiple concentrations used for creating the above calibration curve may have a concentration of zero. That is, even if one of the multiple samples has a concentration of zero and the peak area value at that time is supposed to be zero, a calibration curve may be created based only on the analysis results of a sample of one predetermined concentration (that is, even by the one-point calibration curve method).

[0047] In the state where the information on the retention time and retention index for identification and the calibration curve information for quantification are registered in the compound table 227 as described above, the identification and quantification of PFCA in an unknown sample are carried out as follows.

[0048] When an operator commands the execution of an analysis from the input unit 3, the analysis control unit 21, upon receiving this command, controls the operation of the Py-GC unit 11 and the MS unit 12, respectively, according to the analysis conditions stored in the analysis condition storage unit 211. When the unknown sample to be analyzed is introduced into the pyrolysis furnace of the pyrolysis unit 111, the unknown sample is pyrolyzed in the pyrolysis furnace heated to a predetermined temperature (e.g., 700°C). The resulting pyrolysis products are transported to the sample introduction unit 112 by a carrier gas (e.g., He), and a portion of them is introduced into the column 115. If the unknown sample contains PFCA, carbon fluoride with a structure corresponding to the type of PFCA is produced as a pyrolysis product, and this carbon fluoride is introduced into the column 115.

[0049] Under the control of the analytical control unit 21, the column oven 114 is heated according to a predetermined temperature profile as shown in Figure 5. Each component, such as fluorinated carbon, introduced into the column 115 is separated over time as it passes through the column 115 and elutes from the outlet of the column 115, and is introduced into the ionization unit 122 of the MS unit 12. The components introduced into the ionization unit 122 are ionized by the EI method, and the generated ions are introduced into the quadrupole mass filter 124 through the ion lens 123. As described above, fragmentation is promoted during ionization in the EI method, so fluorinated carbons with different structures introduced into the ionization unit 122 generate a common fragment ion with the same m / z.

[0050] Under the control of the analysis control unit 21, the quadrupole mass filter 124 is driven to repeatedly perform SIM measurements targeting a specific set of m / z values ​​(e.g., m / z 69, m / z 131, etc.). Ions that pass through the quadrupole mass filter 124 reach the detector 125. The detector 125 continuously generates an intensity signal corresponding to the amount of ions that have reached it and sends it to the data processing unit 22. In the data processing unit 22, the data storage unit 221 digitizes and stores the ion intensity signal.

[0051] The chromatogram generation unit 222 creates an EIC at, for example, m / z 131, one of the fragment ions of carbon fluoride, based on the collected data. The peak detection unit 223 detects peaks in the EIC. As described above, since the carbon fluoride products, which are thermal decomposition products, elute at different retention times, the retention times of the peaks observed in the EIC can be used to identify PFCA. Therefore, the identification unit 224 determines the retention time (RT) of one or more detected peaks and identifies the PFCA corresponding to each peak by comparing these retention times with the retention times in the compound table 227 stored in the compound information storage unit 226. Identification may also be performed using a retention index instead of retention time.

[0052] Furthermore, the quantitative analysis unit 225 calculates the area value of the peak detected in the EIC, and determines the concentration by comparing the sensitivity coefficient calculated from that peak area value with the calibration curve in the compound table 227. As mentioned above, the calibration curve is prepared in advance using readily available PFCA standard samples, but since a common calibration curve can be used even if the number of carbon atoms differs, the concentration can be determined with reasonable accuracy. The information obtained in this way regarding the type of PFCA contained in the unknown sample and its concentration is displayed on the screen of the display unit 4 and provided to the user.

[0053] In the above explanation, calibration information obtained by measuring a standard sample of a specific PFCA is used not only for the quantification of that specific PFCA, but also for the quantification of other PFCAs. That is, common calibration information is used for the quantification of multiple types of compounds belonging to PFCA. In contrast, according to the inventors' studies, it has been confirmed that PFSA can also be quantified with sufficient accuracy by performing Py-GC / MS in the presence of a basic solution as described above and creating an EIC at a specific m / z, using the calibration information obtained using PFCA. Furthermore, it has been confirmed that not only PFCA and PFSA, but also other PFASs can be quantified using the calibration information obtained using PFCA. The accuracy of this quantification is considered sufficient for screening purposes. It is presumed that the reason a common calibration curve can be used in this way is that all PFAS have the basic unit R-(CF2)-C(F)(R')R'' (wherein the CF2 and CF portions are both saturated carbon, and the R group (R, R', or R'') is not hydrogen).

[0054] Therefore, by creating a calibration curve using a standard sample for a specific PFCA (or PFAS), it is possible to roughly quantify any or at least several compounds belonging to PFAS using that calibration curve. Of course, to perform more accurate quantification, it is desirable to use calibration information obtained using standard samples of compounds with more similar structures, for example, obtaining calibration information using a standard sample of PFCA when quantifying compounds belonging to PFCA.

[0055] [Other Examples of Quantitative Methods] When a user performs the calibration information creation work described above, that user is required to measure at least one standard sample of PFCA (or PFAS). In contrast, by adopting the following quantitative method, the user can obtain the information necessary for the quantification of PFCA (or PFAS) in an unknown sample by measuring a reference substance that is more readily available, rather than a standard sample of PFCA (or PFAS).

[0056] In this method, for example, the instrument manufacturer calculates the relative response factor (RRF) using measurement results for readily available PFCA standard samples and measurement results for reference substances such as PFOA, and stores this relative response factor as calibration information. The user then uses this relative response factor to quantify PFCA for which standard samples are not available.

[0057] Specifically, the manufacturer performs analysis using a Py-GC / MS instrument on a standard sample of PFCA with a known concentration and a reference substance with a known concentration, and creates an EIC at a predetermined m / z, for example, m / z 131, and calculates the ratio of the peak area values ​​of the two. Then, they calculate the relative sensitivity coefficient from the relationship between the concentration ratio and the ratio of the peak area values. Finally, they register this relative sensitivity coefficient in compound table 227.

[0058] When a user quantifies PFCA in an unknown sample, they perform analysis of the unknown sample using a Py-GC / MS instrument, and immediately before or after (within a time frame in which no change in the analysis results can be considered) analyze the reference substance using a Py-GC / MS instrument. Now, if the sensitivity coefficient of PFCA in the unknown sample is RFn and the sensitivity coefficient of the reference substance is RFs, then RFn = RRF × RFs.

[0059] Since both RFn and RFs are [peak area value / mass of target component], the above equation can be transformed as follows: Peak area value of PFCA in unknown sample / Mass of PFCA in unknown sample = RRF × (peak area of ​​reference substance / mass of reference substance) Mass of PFCA in unknown sample = Peak area value of PFCA in unknown sample × {1 / (RRF × (peak area of ​​reference substance / mass of reference substance))}

[0060] To determine the concentration of PFCA in an unknown sample, divide both sides of the above equation by the mass of the unknown sample (resin). Therefore, the concentration of PFCA in the unknown sample = Peak area value of PFCA in the unknown sample × {1 / (RRF × (Peak area value of reference substance / Mass of reference substance))} × (1 / Mass of unknown sample). In this way, the concentration of PFCA can be calculated, or PFCA can be quantified, using the detected peak area value of PFCA in the unknown sample, the sensitivity coefficient of the reference substance, and the relative sensitivity coefficient.

[0061] This method allows users to quantify various compounds belonging to PFCA with sufficient accuracy by measuring readily available reference substances. Furthermore, this method can be extended to PFAS other than PFCA, enabling the quantification of various compounds belonging to PFCA with reasonable accuracy.

[0062] [Use of concentration values ​​converted to specific PFAS] In the explanation so far, calibration information obtained based on the results obtained by analyzing a particular compound belonging to PFAS, such as PFCA, with a Py-GC / MS instrument was used not only for the quantification of that compound but also for the quantification of other compounds belonging to PFAS. This was based on the premise of determining the concentration of one or more compounds contained in the sample individually, but there is also a demand to comprehensively understand the total PFAS concentration rather than those of individual compounds.

[0063] As mentioned above, according to the definition of PFAS as a chemical substance having at least a perfluorinated methyl group (-CF3) or a perfluorinated methylene group (-CF2), it is said that there are more than 10,000 types of compounds belonging to PFAS, and the total PFAS includes such an extremely large number of compounds. It is practically impossible to obtain standard samples for each of them and perform analysis. In contrast, when analyzed with a Py-GC / MS instrument, carbon fluoride, which is a thermal decomposition product, is generated from all PFAS contained in the sample, so peaks corresponding to fragment ions specific to carbon fluoride observed at m / z 69, m / z 131, etc. can be considered to originate from PFAS.

[0064] As mentioned above, even for PFAS with different carbon chain lengths (number of carbon atoms), if a calibration curve is created using fragment ions with specific m / z values ​​such as m / z 131, the slope of the calibration curve will be almost the same. Therefore, even if a calibration curve created for a specific PFAS is applied to a different PFAS, a quantitative value with reasonable accuracy can be obtained. Thus, the total concentration of PFAS contained in the sample, in other words, the total concentration of PFAS based on a specific PFAS, can be determined as follows.

[0065] First, a standard sample of a specific PFAS (e.g., PFOA) of known concentration is analyzed in the measurement unit 1 under predetermined analytical conditions, for example, provided by the instrument manufacturer. Based on the results, the data processing unit 2 creates a calibration curve for the sensitivity coefficient. As the quantitative ion during measurement, a fragment ion of carbon fluoride (e.g., m / z 69, m / z 131, etc.) that is commonly detected in all PFAS is set. Next, an unknown sample is analyzed in the measurement unit 1 under the same analytical conditions, and the sensitivity coefficient obtained from the area value of the peak detected on the resulting EIC is quantified against the calibration curve. If the unknown sample contains multiple types of different PFAS, multiple peaks will be observed corresponding to these multiple PFAS. In that case, the area values ​​of the multiple peaks are added together, the sensitivity coefficient is calculated from the summation, and the concentration is determined by comparing this sensitivity coefficient against the calibration curve. In this way, the concentration value of the total PFAS of the unknown sample, converted to the reference PFAS (e.g., PFOA), can be obtained.

[0066] Furthermore, when determining the total PFAS concentration, the area values ​​of the peaks on the EIC corresponding to each PFAS-derived carbon fluoride are summed up, so it is not necessary for the carbon fluoride from each PFAS to be completely separated in GC. Therefore, separation conditions that would achieve high separation performance to sufficiently separate structurally different carbon fluorides, such as using a plotting column, are unnecessary.

[0067] For example, when analyzing total PFAS at multiple different analytical and research institutions, it becomes possible to compare the concentrations of total PFAS across these institutions by calculating the concentration value converted to a single standard PFAS. In other words, a common standard can be used to compare the concentrations of total PFAS across multiple analytical institutions, companies, universities, etc. Furthermore, by selecting highly toxic PFAS such as PFOA and PFOS as the standard PFAS, it becomes possible to obtain converted concentration values ​​that can be used to take countermeasures from a risk management perspective. Although highly accurate quantification is difficult because the same calibration curve is used for all PFAS, it is perfectly usable for purposes such as screening analysis, where you want to know whether a compound is present or not, and if so, approximately what concentration it is at.

[0068] The above embodiments and modifications are merely examples of the present invention, and it is clear that any modifications, changes, or additions made within the scope of the present invention will be included within the scope of the claims of this patent application.

[0069] [Embodiments] The exemplary embodiments described above will be understood by those skilled in the art to be specific examples of the following embodiments.

[0070] (Section 1) One aspect of the method for analyzing organofluorine compounds according to the present invention is an analytical method for analyzing PFAS in a sample, comprising: a measurement step of performing pyrolysis gas chromatography-mass spectrometry on one or a plurality of standard samples of PFAS having a carbon chain with a predetermined number of carbon atoms, at a predetermined concentration, and collecting data; a calibration information acquisition step of creating an EIC in the mass-to-charge ratio of fragment ions derived from fluorinated carbon, which is a pyrolysis product, and commonly observed in PFAS, for each of the one or a plurality of standard samples of the predetermined concentration, and obtaining calibration information using the peak information on the EIC, an unknown sample measurement step of performing pyrolysis gas chromatography-mass spectrometry on an unknown sample of PFAS having a carbon chain with a predetermined number of carbon atoms or a value other than the predetermined value, and collecting data; and a chromatogram creation step of creating an unknown sample EIC in the mass-to-charge ratio based on the data obtained in the unknown sample measurement step. The method includes a quantitative step of determining the quantitative value of PFAS in the unknown sample using the peak information on the unknown sample EIC and the calibration information.

[0071] (Section 7) One embodiment of the organofluorine compound analyzer according to the present invention is an analyzer for analyzing PFAS in a sample, comprising: a storage unit that stores calibration information obtained using peak information observed in the EIC, which is the mass-to-charge ratio of fragment ions derived from fluorinated carbon, a pyrolysis product, and commonly observed in PFAS, and is created based on data collected by performing pyrolysis gas chromatography-mass spectrometry on one or a plurality of standard samples of predetermined concentrations of PFAS having a carbon chain with a predetermined number of carbons; a measurement unit that is a pyrolysis gas chromatography-mass analyzer; a chromatogram creation unit that creates an unknown sample EIC in the mass-to-charge ratio based on data collected by measurement by the measurement unit on an unknown sample of PFAS having a carbon chain with a predetermined number of carbons or a value other than the predetermined number; and a quantitative unit that determines the quantitative value of PFAS in the unknown sample using the peak information observed in the unknown sample EIC and the calibration information stored in the storage unit.

[0072] (Item 10) In the organofluorine compound analyzer described in Item 7, the chromatogram creation unit may include a calibration information creation unit that creates an EIC in the mass-to-charge ratio based on data collected by the measurement unit for a standard sample of PFAS having a carbon chain with a predetermined number of carbon atoms, and further creates calibration information using peak information on the EIC and stores it in the storage unit.

[0073] According to the method for analyzing organic fluorine compounds described in paragraph 1, or the organic fluorine compound analyzer described in paragraph 7 or 10, calibration information obtained by analyzing a readily available standard sample of a specific PFAS is used to quantify PFAS of a different type (with a different number of carbon atoms in the carbon chain). This eliminates the need for the cumbersome process of preparing a standard sample for each PFAS to be quantified and then analyzing that standard sample to create calibration information, thereby reducing the effort and cost required for quantifying PFAS in a sample. Furthermore, it becomes possible to quantify PFAS of types for which standard samples are generally difficult or practically unavailable, making it easier to understand the various PFAS contained in products or present in the environment.

[0074] Furthermore, with the organofluorine compound analyzer described in Section 10, calibration information can be created based on the results of measuring standard PFAS samples prepared by the user. This enables more accurate quantification that reflects variations in analytical conditions.

[0075] (Paragraph 2) In the method for analyzing organofluorine compounds described in Paragraph 1, the calibration information may be a calibration curve showing the relationship between concentration and peak area value or sensitivity coefficient.

[0076] (Clause 8) In the organofluorine compound analyzer described in paragraph 7, the calibration information may be a calibration curve showing the relationship between concentration and peak area value or sensitivity coefficient.

[0077] (Section 3) In the method for analyzing organofluorine compounds described in Section 1, the calibration information is a relative sensitivity coefficient with respect to a reference substance, and in the quantitative step, the quantitative value of PFAS in the unknown sample can be determined by also utilizing the analytical results for the reference substance.

[0078] (Section 9) In the organofluorine compound analyzer described in Section 7, the calibration information is a relative sensitivity coefficient with respect to a reference substance, and the quantitative unit can determine the quantitative value of PFAS in the unknown sample by also utilizing the analysis results for the previous reference substance.

[0079] (Article 4) The method for analyzing organofluorine compounds described in any one of paragraphs 1 to 3, further comprising: a measurement step in which pyrolysis gas chromatography-mass spectrometry is performed on standard samples of multiple types of PFAS with different numbers of carbon atoms to collect data; a retention time acquisition step in which EICs in the mass-to-charge ratio are created for each of the multiple types of PFAS based on the data obtained in the measurement step, and the retention time is determined from the peaks on the EICs; a relational formula calculation step in which a relational formula showing the relationship between the number of carbon atoms and the retention time is calculated based on the retention times obtained for each of the multiple types of PFAS; and an identification step in which the type of PFAS contained in the unknown sample is identified using the retention time obtained from the relational formula or the retention index calculated from the retention time for the peaks on the EIC of the unknown sample.

[0080] (Item 11) In the organofluorine compound analyzer described in any one of items 7 to 10, the memory unit stores a relational expression showing the relationship between the number of carbon atoms and the retention time, which is obtained from the retention time obtained from the retention time obtained from peak information observed in the EIC of the mass-to-charge ratio of fragment ions, which are derived from fluorinated carbon, a pyrolysis product and commonly observed in PFAS, or information on the retention time for each type of PFAS obtained from the relational expression or the retention index calculated from the retention time, and further, an identification unit that identifies the type of PFAS contained in the unknown sample using any of the relational expression, retention time, or retention index stored in the memory unit for the peak on the EIC of the unknown sample.

[0081] In other words, the organofluorine compound analysis method described in paragraph 4 or the organofluorine compound analyzer described in paragraph 11 stores in its memory not only calibration information for quantification, but also retention time or retention index for identifying the type of PFAS, or information (relational formulas) that can easily derive these. Therefore, the type of PFAS contained in the sample can be easily and accurately identified and then quantified.

[0082] (Item 5) In the method for analyzing organofluorine compounds described in any one of items 1 to 4, the quantitative step may involve summing the area values ​​of multiple peaks observed in the unknown sample EIC and determining the quantitative value of the total PFAS by comparing the sum with the calibration information.

[0083] (Item 12) In the organofluorine compound analyzer described in any one of items 7 to 11, the quantitative unit may determine the quantitative value of the total PFAS by summing the area values ​​of multiple peaks observed in the unknown sample EIC and comparing the sum with the calibration information.

[0084] According to the method for analyzing organic fluorine compounds described in paragraph 5 or the apparatus for analyzing organic fluorine compounds described in paragraph 12, it is possible to determine not only the individual concentrations of specific types of PFAS, but also the total concentration of PFAS.

[0085] (Paragraphs 6 and 13) In the method for analyzing organofluorine compounds described in any one of paragraphs 1 to 5, or in the apparatus for analyzing organofluorine compounds described in any one of paragraphs 7 to 12, the mass-to-charge ratio of the fragment ions may be m / z 69 or m / z 131.

[0086] m / z 69 and m / z 131 are ions that are well observed in various PFAS, among the various fragment ions derived from carbon fluoride, which is a thermal decomposition product of PFAS. Therefore, the organofluorine compound analysis method described in Section 6 or the organofluorine compound analyzer described in Section 13 can perform identification and quantification with higher accuracy compared to using fragment ions of other m / z.

[0087] 1...Measurement unit 11...Py-GC unit 111...Pyrolysis unit 112...Sample introduction unit 113...Carrier gas flow path 114...Column oven 115...Column 12...MS unit 121...Vacuum chamber 122...Ionization unit 123...Ion lens 124...Quadrupole mass filter 125...Detector 2...Control and processing unit 21...Analysis control unit 211...Analysis condition storage unit 22...Data processing unit 221...Data storage unit 222...Chromatogram creation unit 223...Peak detection unit 224...Identification unit 225...Quantification unit 226...Compound information storage unit 3...Input unit 4...Display unit

Claims

1. An analytical method for analyzing PFAS (perfluoroalkyl compounds and polyfluoroalkyl compounds) in a sample, comprising: a measurement step of performing pyrolysis gas chromatography-mass spectrometry on one or more standard samples of PFAS having a carbon chain with a predetermined number of carbon atoms, at a predetermined concentration, and collecting data; a calibration information acquisition step of creating an extracted ion chromatogram for each of the one or more standard samples of the predetermined concentration, based on the data obtained in the measurement step, at the mass-to-charge ratio of fragment ions derived from fluorinated carbon, which is a pyrolysis product, and commonly observed in PFAS, and obtaining calibration information using the peak information on the extracted ion chromatogram; an unknown sample measurement step of performing pyrolysis gas chromatography-mass spectrometry on an unknown sample of PFAS having a carbon chain with a predetermined number of carbon atoms or a value other than the predetermined number, and collecting data; and a chromatogram creation step of creating an extracted ion chromatogram of the unknown sample at the mass-to-charge ratio based on the data obtained in the actual sample measurement step. A method for analyzing organofluorine compounds, comprising: a quantitative step of determining the quantitative value of PFAS in the unknown sample using the peak information on the ion chromatogram of the unknown sample and the calibration information.

2. The method for analyzing organofluorine compounds according to claim 1, wherein the calibration information is a calibration curve showing the relationship between concentration and peak area value or sensitivity coefficient.

3. The method for analyzing organofluorine compounds according to claim 1, wherein the calibration information is a relative sensitivity coefficient with respect to a reference substance, and in the quantitative step, the quantitative value of PFAS in the unknown sample is determined by also utilizing the analytical results for the reference substance.

4. The method for analyzing organofluorine compounds according to claim 1, further comprising: a measurement step in which pyrolysis gas chromatography-mass spectrometry is performed on standard samples of multiple types of PFAS with different numbers of carbon atoms to collect data; a retention time acquisition step in which extracted ion chromatograms at the mass-to-charge ratio are created for each of the multiple types of PFAS based on the data obtained in the measurement step, and the retention time is determined from the peaks on the extracted ion chromatograms; a relational formula calculation step in which a relational formula showing the relationship between the number of carbon atoms and the retention time is calculated based on the retention times obtained for each of the multiple types of PFAS; and an identification step in which the type of PFAS contained in the unknown sample is identified for the peaks on the extracted ion chromatogram of the unknown sample using the retention time obtained from the relational formula or a retention index calculated from the retention time.

5. The method for analyzing organofluorine compounds according to claim 1, wherein in the quantitative step, the area values ​​of multiple peaks observed in the ion chromatogram of the unknown sample are summed, and the total PFAS is determined by comparing the summed value with the calibration information.

6. The method for analyzing organofluorine compounds according to any one of claims 1 to 5, wherein the mass-to-charge ratio of the fragment ion is m / z 69 or m / z 131.

7. An analytical apparatus for analyzing PFAS (perfluoroalkyl compounds and polyfluoroalkyl compounds) in a sample, comprising: a storage unit for storing calibration information obtained using peak information observed in an extracted ion chromatogram of fragment ions in the mass-to-charge ratio derived from carbon fluoride, a pyrolysis product, which is commonly observed in PFAS, and which is created based on data collected by performing pyrolysis gas chromatography-mass spectrometry on one or more standard samples of PFAS having a carbon chain with a predetermined number of carbon atoms at a predetermined concentration; a measurement unit which is a pyrolysis gas chromatography-mass spectrometer; a chromatogram creation unit which creates an extracted ion chromatogram of an unknown sample in the mass-to-charge ratio based on data collected by measurement by the measurement unit on an unknown sample of PFAS having a carbon chain with a predetermined number of carbon atoms or a value other than the predetermined number; and a quantitative unit which determines the quantitative value of PFAS in the unknown sample using the peak information observed in the extracted ion chromatogram of the unknown sample and the calibration information stored in the storage unit.

8. The organofluorine compound analyzer according to claim 7, wherein the calibration information is a calibration curve showing the relationship between concentration and peak area value or sensitivity coefficient.

9. The organofluorine compound analyzer according to claim 7, wherein the calibration information is a relative sensitivity coefficient with respect to a reference substance, and the quantitative unit determines the quantitative value of PFAS in the unknown sample using the analysis results for the previous reference substance as well.

10. The organofluorine compound analyzer according to claim 7, wherein the chromatogram preparation unit prepares an extracted ion chromatogram at the mass-to-charge ratio based on data collected by the measurement unit for a standard sample of PFAS having a carbon chain with a predetermined number of carbon atoms, and further prepares calibration information using peak information on the extracted ion chromatogram and stores it in the storage unit.

11. The organofluorine compound analyzer according to claim 7, wherein the storage unit stores a relational expression showing the relationship between the number of carbon atoms and the retention time, which is obtained from the retention time obtained from the retention time obtained from the peak information observed in the extracted ion chromatogram of the mass-charge ratio of fragment ions, which are derived from carbon fluoride, a pyrolysis product and commonly observed in PFAS, or information on the retention time for each type of PFAS obtained from the relational expression or the retention index calculated from the retention time, and further comprises an identification unit that identifies the type of PFAS contained in the unknown sample using any of the relational expression, retention time, or retention index stored in the storage unit for the peak on the extracted ion chromatogram of the unknown sample.

12. The organofluorine compound analyzer according to claim 7, wherein the quantitative unit sums the area values ​​of multiple peaks observed in the unknown sample extraction ion chromatogram and determines the quantitative value of the total PFAS by comparing the sum with the calibration information.

13. The organofluorine compound analyzer according to any one of claims 7 to 12, wherein the mass-to-charge ratio of the fragment ion is m / z 69 or m / z 131.

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