Fluororesin analysis method and analysis device

Abstract

One embodiment of a fluororesin analysis device according to the present invention is a device that analyzes a fluororesin contained in a sample, and comprises: a measurement unit (1) that is a Py-CG / MS device; a chromatogram creation unit (222) that creates, from data collected using measurements performed on a target sample by the measurement unit, an EIC for fluorocarbon-derived fragment ions that are generated from thermal decomposition and has a specific m / z value; and an assessment unit (223, 224) that assesses whether a fluororesin is present by determining whether peak emergence has periodicity with respect to the retention time in the EIC. As a result, it can be assessed whether a sample contains a fluororesin even if there is no database for identifying the fluororesin.

Description

Fluororesin analysis method and analyzer

[0001] The present invention relates to a method and an apparatus for analyzing fluororesin.

[0002] Fluororesin is a general term for plastics (resins) containing fluorine atoms and has characteristics such as high heat resistance, cold resistance, chemical resistance, and insulation. A typical fluororesin is polytetrafluoroethylene (PTFE) known as Teflon (registered trademark). In addition, perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), etc. are known.

[0003] The above-mentioned fluororesin is a kind of PFAS (Per and poly FluoroAlkyl Substances), which has been attracting attention in recent years. For some compounds belonging to PFAS, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), etc., there are concerns about their harmfulness to humans and organisms, and moreover, due to their high persistence and bioaccumulation, the movement to prohibit or regulate their use and manufacture is spreading in various countries. On the other hand, PTFE is recognized as having no concerns like other low molecular weight PFAS.

[0004] Perfluorocarboxylic acids (PFCAs) containing PFOA and perfluorosulfonic acids (PFSAs) containing PFSAs are often incorporated into resins as additives or applied to resin surfaces as coating agents. Conventionally, a common method for analyzing PFAS in this form is to extract the target component in an organic solvent (methanol) and then analyze the extract using liquid chromatography-tandem mass spectrometry (LC / MS / MS) (for example, the test method in the standard "EN 17681-1:2022" created and published by the European Committee for Standardization (CEN)). However, this conventional method has drawbacks, such as the fact that the pretreatment is quite complicated and time-consuming and costly, and that the amount of compound extracted varies depending on the type of resin being extracted, as the degree of methanol penetration differs.

[0005] Chiara Gnoffo and 1 other person, “Identification of Plastics in Mixtures and Blends through Pyrolysis-Gas Chromatography / Mass Spectrometry”, Polymers, 2024, Vol. 16, Issue 1, 71

[0006] In response to this, there have recently been reports of attempts to analyze PFAS using pyrolysis gas chromatography-mass spectrometry (Py-GC / MS) equipment. For example, Non-Patent Literature 1 describes a method for identifying fluororesins by comparing the analysis results of fluororesins using Py-GC / MS equipment with a pre-established database.

[0007] However, the method described in Non-Patent Document 1 cannot identify or confirm the existence of fluororesins that are not listed in the database. In particular, given the recent strengthening of regulations on compounds belonging to PFAS, as mentioned above, being able to determine whether a sample is a fluororesin or not, or whether it contains a fluororesin, even if it cannot identify the type of resin, has great technical significance.

[0008] This invention has been made in view of these problems, and its main objective is to provide a fluororesin analysis method and analytical apparatus that can accurately determine whether or not a sample contains fluororesin, even when there is no database for identification or quantification.

[0009] One embodiment of the fluororesin analysis method according to the present invention is an analytical method for analyzing fluororesins contained in a sample, comprising: a measurement execution step of performing measurements on a target sample and collecting data using a pyrolysis gas chromatograph mass spectrometer; a chromatogram creation step of creating an extracted ion chromatogram of fragment ions having a specific mass-to-charge ratio derived from carbon fluoride produced by pyrolysis from the data obtained in the measurement execution step; and a determination step of determining whether or not fluororesins are present by determining whether or not the appearance of peaks with respect to retention time in the extracted ion chromatogram has periodicity.

[0010] Furthermore, one embodiment of the fluororesin analyzer according to the present invention is an apparatus for analyzing fluororesins contained in a sample, comprising: a measurement unit which is a pyrolysis gas chromatograph mass spectrometer; a chromatogram creation unit which creates an extracted ion chromatogram of fragment ions having a specific mass-to-charge ratio derived from carbon fluoride produced by pyrolysis from data collected by measurement by the measurement unit on a target sample; and a determination unit which determines whether or not fluororesins are present by determining whether or not the appearance of peaks with respect to retention time in the extracted ion chromatogram has periodicity.

[0011] According to the above-described embodiment of the fluororesin analysis method and fluororesin analyzer of the present invention, it is possible to easily and accurately determine whether or not a sample contains fluororesin without using a database for identification or quantification. For example, by screening a sample using the fluororesin analysis method of the present invention to determine whether or not it contains fluororesin, it is then possible to check only for samples that have been confirmed to contain fluororesin whether or not they are PFAS subject to regulation, and / or the amount of PFAS present. This makes it possible to efficiently perform analysis of PFAS that are subject to restrictions or prohibitions on use.

[0012] A diagram illustrating the overall configuration of a fluororesin analyzer according to one embodiment of the present invention. A schematic diagram illustrating the method for determining fluororesin content in the fluororesin analyzer of this embodiment. A flowchart showing an example of a specific procedure for determining fluororesin content in the fluororesin analyzer of this embodiment. A flowchart showing another example of the procedure for determining fluororesin content in the fluororesin analyzer of this embodiment. A diagram illustrating a specific method for determining fluororesin content. A diagram showing an example of the analytical conditions in the fluororesin analyzer of this embodiment. A diagram showing actual measurement examples of extracted ion chromatograms at m / z 69 and m / z 131 when the sample contains fluororesin.

[0013] [Configuration of a Fluoropolymer Analyzer in One Embodiment] Hereinafter, a fluoropolymer analyzer and a method for determining the fluoropolymer content using this apparatus, which are embodiments of one embodiment, will be described with reference to the attached drawings. Figure 1 is a schematic configuration diagram of the fluoropolymer analyzer of this embodiment. As shown in Figure 1, this fluoropolymer analyzer uses a Py-GC / MS apparatus and includes a measurement unit 1 and a control / processing unit 2.

[0014] 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.

[0015] 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.

[0016] 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 You can use "2020 NX".

[0017] 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, a peak periodicity determination unit 224, and a determination result output unit 225. 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.

[0018] To perform fluororesin analysis, the computer constituting the control and processing unit 2 has an analysis method for fluororesin analysis installed. This analysis method is a type of software and includes various information on analysis conditions stored in the analysis condition storage unit 211.

[0019] [Principle of Determining Fluororesin Content] An overview of the method for determining whether or not a sample contains fluororesin in the fluororesin analyzer of this embodiment will be explained with reference to Figure 2. As previously mentioned, although attempts have been made to analyze fluororesins using Py-GC / MS instruments, a database is required to identify and quantify individual fluororesins. Conventional analytical methods have not been able to determine whether or not a sample contains fluororesins for which such a database is not available.

[0020] As also described in Non-Patent Document 1, when PFAS is analyzed using a Py-GC / MS instrument, fragment ions derived from carbon fluoride, which are thermal decomposition products of PFAS, are detected. This is because, when ionization is performed by the EI method in a mass spectrometer, fragmentation preferentially cleaves the weaker bonds of the molecule, and common fragment ions are easily generated from various carbon fluoride molecules with different structures, while retaining the relatively strong bonds. Specifically, fragment ions such as m / z 69 (CF3 ion) and m / z 131 (C3F5 ion) are known to be easily observed.

[0021] The inventors, through repeated experiments analyzing fluororesins using a Py-GC / MS instrument, discovered that when fluororesins are analyzed using a Py-GC / MS instrument under certain analytical conditions, and extracted ion chromatograms (EICs) with m / z 69 and m / z 131 are created, peaks (chromatographic peaks) appear periodically in the EIC with respect to retention time.

[0022] As an example, Figure 7 shows measured EIC values ​​at m / z 69 and m / z 131 obtained by analyzing PTFE, a type of fluorinated resin, using a Py-GC / MS instrument under the analytical conditions shown in Figure 6. As can be seen from Figure 7, numerous peaks appear on the EIC at approximately constant time intervals. Furthermore, the intensities of the peak tops of the multiple periodically appearing peaks are either roughly the same or, as shown in Figure 7, exhibit relatively continuous (non-random) fluctuations in the time direction.

[0023] The reason why such a characteristic peak pattern appears in the EIC at a specific m / z can be inferred as follows: Generally, resins are polymers of monomers and have a repeating structure in which many monomers are bonded together. Fluororesins use carbon to which fluorine is bonded as the monomer. When fluororesins are thermally decomposed, for example, under certain temperature conditions, they decompose sequentially from the points in their repeating structure where the bonding force is relatively weak, producing monomers and oligomers and polymers with various repeating numbers. These oligomers and polymers with different repeating numbers are introduced into a GC column and pass through the column, or pass through the column while undergoing separation operations for each fluorinated carbon, and are introduced into a mass spectrometer. Therefore, by appropriately adjusting the thermal decomposition conditions and the separation conditions in GC, multiple fluorinated carbons originating from one or more fluororesins, each with a different structure (number of carbon atoms in the carbon chain), are introduced into the mass spectrometer at approximately equal time intervals. As a result, it is inferred that peaks appear at approximately equal time intervals on the EIC for fragment ions that appear almost commonly in multiple fluorinated carbons.

[0024] Furthermore, since the intensity of the peak top on the EIC reflects the amount of monomers, oligomers, and polymers produced by thermal decomposition, it is presumed that the pattern of change in peak top intensity over time is influenced by the relationship between the polymer's bond energy and the thermal decomposition temperature. For example, if the thermal decomposition temperature is higher than the polymer's bond energy, a large amount of monomers are produced by thermal decomposition, and therefore the peak top intensity is expected to decrease monotonically over time.

[0025] The periodic appearance of chromatographic peaks as described above is characteristic of fluororesins. Therefore, by creating EICs at m / z 69 and m / z 131, which are characteristic of carbon fluoride, for example, and determining whether or not there is periodicity in the peaks in those EICs, it is possible to determine whether or not a sample contains fluororesin, or whether or not the sample is made of fluororesin. The specific determination method will be described later.

[0026] [Analysis Operation in the Fluoropolymer Analyzer of This Embodiment] An example of the operation when determining whether or not a sample contains fluoropolymer using the fluoropolymer analyzer of this embodiment will be explained with reference to Figure 3 in addition to Figures 1 and 2. Figure 3 is a flowchart showing an example of a specific procedure for determining fluoropolymer content.

[0027] The analysis conditions stored in the analysis condition storage unit 211 include a temperature control program for the pyrolysis unit 111, a gas flow rate (or linear velocity) for the GC unit, and a column oven temperature control program. When the user instructs the analysis to be performed from the input unit 3, the measurement unit 1 performs Py-GC / MS analysis on the unknown sample under the control of the analysis control unit 21 that received the instruction (step S1).

[0028] Specifically, the analysis control unit 21 controls the operation of the Py-GC unit 11 and the MS unit 12 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. 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 fluororesin, carbon fluoride is produced as a pyrolysis product, but carbon fluoride with different structures (different repeating numbers) is produced with slight staggered timing, and the produced carbon fluoride is introduced into the column 115 sequentially.

[0029] Under the control of the analytical control unit 21, the column oven 114 is controlled 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, 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 the fluorinated carbons with different structures introduced into the ionization unit 122 are fragmented, generating a common fragment ion with the same m / z.

[0030] 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 frequencies (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.

[0031] In the data processing unit 22, the data storage unit 221 digitizes and stores the ion intensity signal. The chromatogram creation unit 222 creates an EIC at m / z 131, for example, one of the fragment ions of carbon fluoride, based on the collected data (step S2). Figure 5 is a schematic diagram showing an example of this EIC. The peak detection unit 223 detects peaks in the created EIC according to a predetermined algorithm (step S3). The peak periodicity determination unit 224 determines whether the detected peaks have periodicity.

[0032] Specifically, the peak periodicity determination unit 224 first sets a first retention time interval A (retention time R1 to R2) and a second retention time interval B (retention time R3 to R4) on the EIC, as shown in Figure 5 (step S4). Here, the duration of each retention time interval is the same, i.e., R2 - R1 = R4 - R3. Since the accuracy of the determination may be impaired if a peak falls on the boundary of a retention time interval, it is advisable to appropriately adjust the positions of the first and second retention time intervals A and B so that the boundary of the retention time interval does not fall within the range from the start point to the end point of the peak.

[0033] Next, the peak periodicity determination unit 224 counts the number of peaks included in each retention time interval A and B (step S5), and determines whether the number of peaks in the two retention time intervals is the same, or whether the difference in the number of peaks is within a predetermined threshold (step S6). The predetermined threshold at this time depends on the number of peaks included in the retention time interval, but it is good to set it to a value of about 10% to 20% of the number of peaks. When the number of peaks in the two retention time intervals is the same or the difference in the number of peaks is within the predetermined threshold, the peak periodicity determination unit 224 determines that the unknown sample is a fluororesin (or contains a fluororesin) (step S7), and when the number of peaks in the two retention time intervals is not the same or the difference in the number of peaks exceeds the predetermined threshold, the peak periodicity determination unit 224 determines that the unknown sample is not a fluororesin (or does not contain a fluororesin) (step S8). The determination result output unit 225 displays the result of whether the unknown sample is a fluororesin or not on the display unit 4.

[0034] [Other examples of peak periodicity determination] The method for determining the periodicity of peaks observed in EIC is not limited to those described above, and various variations are possible.

[0035] For example, although two retention time intervals were set in the above explanation, it is also permissible to set three or more retention time intervals, and if the number of peaks obtained in each of these three or more intervals is the same, or if the difference in the number of peaks is within a predetermined threshold, it may be determined that the unknown sample contains fluororesin. Furthermore, when setting multiple retention time intervals, it is permissible for some of them to overlap.

[0036] Furthermore, in order to improve the accuracy of fluororesin detection, other constraints may be added in addition to the condition that the number of peak counts in the retention time intervals is the same. The flowchart shown in Figure 4 is an example in which constraints regarding peak intensity have been added. Steps that perform substantially the same processing as those in the flowchart shown in Figure 3 are given the same step numbers and their explanations are omitted.

[0037] As described above, the peak intensities of the peak tops of chromatographic peaks corresponding to different carbon fluoride derived from fluororesins are approximately the same or show relatively continuous fluctuations over time. Therefore, in order to confirm whether the peak to be used for periodicity determination is indeed a peak derived from carbon fluoride, if the peak periodicity determination unit 224 determines Yes in step S6, it then calculates the average value of the peak top intensities in each of the multiple retention time intervals A and B (step S10).

[0038] Then, it is determined whether the difference in the average values ​​of the strengths in multiple retention time intervals A and B is below a predetermined threshold (step S11). If it is below the predetermined threshold, that is, if the difference in the average values ​​of the strengths is small or not extremely large, it is determined that the unknown sample is a fluororesin. This makes it possible to determine whether or not it is a fluororesin more accurately.

[0039] Alternatively, instead of the processes in steps S10 and S11 described above, it may be possible to confirm whether the peak whose periodicity is to be determined is indeed a peak originating from fluorinated carbon by other determination methods related to peak intensity.

[0040] For example, the difference in peak intensity between two adjacent peaks in the time direction may be calculated sequentially, and if the proportion of peak combinations where the difference is within a predetermined threshold exceeds a predetermined percentage of all peak combinations, the unknown sample may be determined to be a fluororesin. Alternatively, the deviation of the peak top intensities of multiple peaks may be calculated, and if the deviation is within a predetermined threshold, the unknown sample may be determined to be a fluororesin. Furthermore, instead of making such determinations about the peak top intensity of each individual peak, for example, a predetermined number of adjacent peaks in the time direction may be grouped together, the average peak top intensity of the grouped number of peaks may be calculated, and the difference between these average intensities or the deviation may be calculated.

[0041] Furthermore, in addition to determining the periodicity of a peak based on the number of peaks in multiple retention time intervals as described above, the retention time difference can be detected by pairing two adjacent peaks, and if the retention time difference for a predetermined number of peak pairs is below a predetermined threshold, it can be determined that the peak has periodicity. Moreover, various other methods can be employed to determine the periodicity of a peak. In addition, various methods other than those described above can be used to confirm whether the peak being assessed for periodicity is indeed a peak derived from carbon fluoride.

[0042] [Distinguishing between PFAS and interfering components] If the sample contains interfering components other than fluororesins, such as PFAS, and the ions derived from these interfering components have the same m / z as the fragment ions characteristic of carbon fluoride, which is a thermal decomposition product of fluororesins, then the above method may not be able to properly determine whether or not the sample contains fluororesins. Typical interfering components include hydrocarbons.

[0043] In cases where such possibilities exist, fluororesins and interfering components such as hydrocarbons can be more reliably distinguished as follows. That is, even if the m / z of the fragment ions is the same, the number of carbon atoms is clearly different between fragment ions derived from carbon fluoride and ions derived from hydrocarbons. This is because the fluorine present in the side chain of the former fragment ion has a significantly larger mass than hydrogen. Carbon is 13 Since carbon isotopes are present at a rate of approximately 1.1%, for example, the relative intensity of an ion with m / z M+1 relative to an ion composed of carbon C and hydrogen H (where m / z is M) is 1.1% × number of carbon atoms. In other words, taking m / z 69 as an example, if m / z 69 is an ion of C5H9 derived from hydrocarbons, then the relative intensity of the isotopic ion with m / z 70 is 1.1% × 5 = 5.5%. On the other hand, if m / z 69 is an ion of CF3 derived from carbon fluoride, a thermal decomposition product of fluororesin, then the relative intensity of that isotopic ion is 1.1% × 1 = 1.1%. Thus, there is a clear difference in the intensity of isotopic ions between fragment ions derived from fluororesin and fragment ions derived from hydrocarbons.

[0044] Therefore, in the fluororesin analyzer of the above embodiment, in order to distinguish between fragment ions derived from fluororesin and fragment ions derived from hydrocarbons, it is preferable to additionally provide a fragment ion discrimination unit. The fragment ion discrimination unit, for example, acquires a mass spectrum at the retention time when a chromatographic peak is detected in the EIC of m / z 69, and in that mass spectrum, obtains the ratio of the intensity of fragment ions specific to fluorocarbons (such as m / z 69, m / z 131, etc.) to the intensity of its isotope ions. Then, this intensity ratio is compared with a predetermined threshold value. If the intensity ratio is lower than the threshold value, it is determined that the observed ion peak is derived from fluororesin, and if the intensity ratio is not less than the threshold value, it is determined that the observed ion peak is derived from hydrocarbons.

[0045] This determination may be made either before or after the determination of the periodicity of the chromatographic peak in the EIC. When it is highly likely that the chromatographic peak is due to fragment ions derived from hydrocarbons, the reliability of the determination of the content of fluororesin based on the determination of the periodicity of that chromatographic peak is low. Therefore, the determination result output unit 225 preferably outputs a display indicating that the determination of the presence or absence of fluororesin is impossible.

[0046] Note that the above embodiments and modification examples are merely examples of the present invention, and it is clear that even if appropriate modifications, changes, and additions are made within the scope of the gist of the present invention, they are included in the scope of the claims of this application.

[0047] [Aspect] It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0048] (Section 1) One aspect of the fluororesin analysis method according to the present invention is an analysis method for analyzing fluororesins contained in a sample, comprising: a measurement execution step of performing a measurement on a target sample using a pyrolysis gas chromatograph-mass spectrometer and collecting data; a chromatogram creation step of creating an EIC of fragment ions having a specific mass-to-charge ratio derived from fluorocarbon produced by pyrolysis from the data obtained in the measurement execution step; and a determination step of determining whether or not fluororesins are present by determining whether or not the appearance of peaks with respect to retention time in the EIC has periodicity.

[0049] (Section 5) One embodiment of the fluororesin analyzer according to the present invention is an apparatus for analyzing fluororesins contained in a sample, comprising: a measuring unit which is a pyrolysis gas chromatograph mass spectrometer; a chromatogram creation unit which creates an EIC of fragment ions having a specific mass-to-charge ratio derived from fluorocarbon produced by pyrolysis from data collected by measurement by the measuring unit for a target sample; and a determination unit which determines whether or not fluororesins are present by determining whether or not the appearance of peaks with respect to retention time in the EIC has periodicity.

[0050] According to the fluororesin analysis method described in paragraph 1 or the fluororesin analyzer described in paragraph 5, it is possible to easily and accurately determine whether or not a sample contains fluororesin without using a database for identification or quantification. For example, by screening a sample using the analytical method according to the present invention to determine whether or not it contains fluororesin, it is then possible to check only for samples that have been confirmed to contain fluororesin whether or not they fall under the category of regulated PFAS, or to what amount of PFAS is present. This makes it possible to perform PFAS analysis efficiently.

[0051] (Paragraph 2) In the fluororesin analysis method described in Paragraph 1, the determination step may include a peak counting step in which a plurality of intervals with the same time length but different retention times are set in the EIC and the number of peaks included in each of the plurality of intervals is counted, and a count comparison step in which it is determined that the appearance of peaks has periodicity with respect to retention time when the count values ​​of the peaks in the plurality of intervals are the same or the difference between the count values ​​is within a predetermined threshold.

[0052] (Paragraph 6) In the fluororesin analyzer described in Paragraph 5, the determination unit may include a peak counting unit that sets a plurality of intervals with the same time length but different retention times in EIC and counts the number of peaks included in each of the plurality of intervals, and a count comparison unit that determines that the appearance of peaks has periodicity with respect to retention time when the count values ​​of the peaks in the plurality of intervals are the same or when the difference between the count values ​​is within a predetermined threshold.

[0053] According to the fluororesin analysis method described in paragraph 2 or the fluororesin analysis apparatus described in paragraph 6, it is possible to determine whether or not the appearance of peaks is periodic through simple data processing.

[0054] (3) In the fluororesin analysis method described in paragraph 2, the determination step further includes a peak intensity acquisition step of calculating the cumulative or average value of the peak intensities included in each of the plurality of intervals, and the count value comparison step may determine that the appearance of peaks has periodicity with respect to retention time when the difference between the cumulative or average values ​​in the plurality of intervals is less than or equal to a predetermined threshold, and the count values ​​of the peaks in the plurality of intervals are the same or the difference between the count values ​​is within a predetermined threshold.

[0055] (Clause 7) In the fluororesin analyzer described in paragraph 6, the determination unit further includes a peak intensity acquisition unit that calculates the cumulative value or average value of the peak intensities included in each of the plurality of intervals, and the count value comparison unit may determine that the appearance of peaks has periodicity with respect to retention time when the difference between the cumulative values ​​or average values ​​in the plurality of intervals is less than or equal to a predetermined threshold, and the count values ​​of the peaks in the plurality of intervals are the same or the difference between the count values ​​is within a predetermined threshold.

[0056] The intensity of the peak tops of the chromatographic peaks that appear periodically in response to multiple carbon fluoride molecules is approximately the same, or shows relatively continuous fluctuations over time. Therefore, when calculating the cumulative or average value of the peak intensities contained in each of the multiple intervals, if the difference in the cumulative or average values ​​across the intervals is relatively small, those peaks are likely to be derived from fluororesin. Conversely, if the difference in the cumulative or average values ​​is large, or extremely large, those peaks may not be derived from fluororesin, or may contain other substances that do not. Accordingly, the fluororesin analysis method described in paragraph 3 or the fluororesin analyzer described in paragraph 7 can determine with even greater accuracy whether or not a sample contains fluororesin.

[0057] (Paragraphs 4 and 8) In the fluororesin analysis method described in any one of paragraphs 1 to 3 or the fluororesin analysis apparatus described in any one of paragraphs 5 to 7, the specific mass-to-charge ratio may be m / z 69 or m / z 131.

[0058] There are several types of fragment ions derived from carbon fluoride produced by the thermal decomposition of fluororesins. Specifically, in addition to the aforementioned m / z 69 and m / z 131, other strong fragment ions include m / z 31 (CF), m / z 50 (CF2), m / z 81 (C2F3), m / z 100 (C2F4), m / z 150 (C3F6), and m / z 181 (C4F7), and these fragment ions can also be used. Among these, m / z 69 and m / z 131 can be reliably produced from various carbon fluoride with different numbers of carbon atoms. Therefore, by using m / z 69 or m / z 131 EIC to determine the presence or absence of fluororesins, highly accurate determination can be made, avoiding, for example, overlooking fluororesins.

[0059] 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...Peak periodicity determination unit 225...Determination result output unit 3...Input unit 4...Display unit

Claims

1. A method for analyzing fluororesins contained in a sample, comprising: a measurement execution step of performing measurements on a target sample and collecting data using a pyrolysis gas chromatograph-mass spectrometer; a chromatogram creation step of creating an extracted ion chromatogram of fragment ions having a specific mass-to-charge ratio derived from carbon fluoride produced by pyrolysis from the data obtained in the measurement execution step; and a determination step of determining whether or not fluororesins are present by determining whether or not the appearance of peaks with respect to retention time in the extracted ion chromatogram has periodicity.

2. The fluororesin analysis method according to claim 1, wherein the determination step includes setting a plurality of intervals with the same time length but different retention times in the extracted ion chromatogram, and counting the number of peaks included in each of the plurality of intervals; and determining that the appearance of peaks has periodicity with respect to retention time when the count values ​​of the peaks in the plurality of intervals are the same or the difference between the count values ​​is within a predetermined threshold.

3. The fluororesin analysis method according to claim 2, wherein the determination step further includes a peak intensity acquisition step of calculating the cumulative or average value of the peak intensities included in each of the plurality of intervals, and the count value comparison step determines that the appearance of peaks has periodicity with respect to retention time when the difference between the cumulative or average values ​​in the plurality of intervals is less than or equal to a predetermined threshold, and the count values ​​of the peaks in the plurality of intervals are the same or the difference between the count values ​​is within a predetermined threshold.

4. The method for analyzing fluororesin according to any one of claims 1 to 4, wherein the specific mass-to-charge ratio is m / z 69 or m / z 131.

5. A fluororesin analyzer comprising: a measuring unit which is a pyrolysis gas chromatograph mass spectrometer; a chromatogram creation unit which creates an extracted ion chromatogram of fragment ions having a specific mass-to-charge ratio derived from carbon fluoride produced by pyrolysis from data collected by the measuring unit for a target sample; and a determination unit which determines whether or not fluororesin is present by determining whether or not the appearance of peaks in the extracted ion chromatogram has periodicity with respect to retention time.

6. The fluororesin analyzer according to claim 5, wherein the determination unit comprises: a peak counting unit that sets a plurality of intervals with the same time length but different retention times in the extracted ion chromatogram and counts the number of peaks contained in each of the plurality of intervals; and a count comparison unit that determines that the appearance of peaks has periodicity with respect to retention time when the count values ​​of the peaks in the plurality of intervals are the same or the difference between the count values ​​is within a predetermined threshold.

7. The fluororesin analyzer according to claim 6, wherein the determination unit further includes a peak intensity acquisition unit that calculates the cumulative or average value of the peak intensities included in each of the plurality of intervals, and the count value comparison unit determines that the appearance of peaks has periodicity with respect to the retention time when the difference between the cumulative or average values ​​in the plurality of intervals is less than or equal to a predetermined threshold, and the count values ​​of the peaks in the plurality of intervals are the same or the difference between their count values ​​is within a predetermined threshold.

8. The fluoropolymer analyzer according to claim 5, wherein the specific mass-to-charge ratio is m / z 69 or m / z 131.

Images