Degradable gas quantitative analysis method

Abstract

The purpose of the present invention is to provide a degradable gas quantitative analysis method which exhibits excellent degradable gas quantitative analysis operability and accuracy. The present invention is a method for quantitatively analyzing a degradable gas contained in a sample by using a gas chromatograph equipped with a pulse discharge ionization detector, wherein the pulse discharge ionization detector is calibrated using a prescribed alternative gas as a standard gas before introducing the sample into the gas chromatograph.

Description

Quantitative analysis method for decomposition gases

[0001] The present invention relates to a method for quantitatively analyzing decomposition gases.

[0002] Gas chromatography is a well-known analytical technique used to separate and analyze specific gas compounds contained in a sample, and is particularly useful as a method for quantitatively analyzing specific gas compounds (e.g., Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2007-057371

[0004] Here, when quantitatively analyzing a gas compound to be measured in a sample using a gas chromatograph, the detector is usually calibrated using a standard gas (standard substance) of the gas compound with a known concentration, and the concentration of the gas compound in the sample can be calculated using the calibrated detector.

[0005] However, when the measurement target is an unstable decomposition gas, the concentration of the decomposition gas changes over time, making it difficult to obtain a decomposition gas with a known concentration. Therefore, when quantitatively analyzing the decomposition gas in a sample, the detector is calibrated using a stable alternative gas as the standard gas instead of the decomposition gas. However, selecting the alternative gas is not easy, and there are problems such as low measurement accuracy.

[0006] On the other hand, as a method for quantitatively analyzing decomposable gases, a method using a gas chromatograph with an ICP mass spectrometer as a detector (so-called "GC-ICP-MS") is known. However, the measurement operation is complicated and difficult to handle in terms of operability, and there is a problem that quantitative analysis is time-consuming when, for example, there are a large number of samples to be measured.

[0007] Therefore, an object of the present invention is to provide a method for quantitatively analyzing decomposable gases that is excellent in operability and accuracy of quantitative analysis of decomposable gases.

[0008] The present inventors have conducted extensive research with the aim of solving the above-mentioned problems, and have newly discovered that the above-mentioned problems can be solved by a method for quantitatively analyzing decomposable gases contained in a sample using a gas chromatograph equipped with a pulse discharge ionization detector, in which the pulse discharge ionization detector is calibrated using a predetermined alternative gas as a standard gas before the sample is introduced into the gas chromatograph, and have completed the present invention.

[0009] That is, the present invention aims to advantageously solve the above-mentioned problems, and provides a method for quantitatively analyzing a decomposable gas contained in a sample using a gas chromatograph equipped with a pulsed discharge ionization detector, comprising: determining an energy difference between the photon energy obtained by the emission of a discharge gas used in the pulsed discharge ionization detector and the ionization energy of the decomposable gas as ΔIE before the sample is introduced into the gas chromatograph; １ The energy difference between the photon energy obtained by the emission of the discharge gas used in the pulse discharge ionization detector and the ionization energy of the alternative gas is defined as ΔIE ２ In this case, ΔIE １ and ΔIE ２This is a quantitative analysis method for decomposable gases, in which the pulse discharge ionization detector is calibrated using an alternative gas as a standard gas whose difference from the standard gas is between -1 eV and 1 eV. In this specification, the elements or compounds constituting the decomposable gas and the alternative gas are not particularly limited as long as they are gases when analyzed by gas chromatography, and may be gases, liquids, or solids at room temperature (approximately 25°C). In this specification, the elements or compounds constituting the alternative gas are typically elements or compounds that are more stable than the elements or compounds constituting the decomposable gas. In this specification, the photon energy obtained by the emission of light from the discharge gas is calculated by a quantum mechanical calculation method using "B3LYP" as the density functional method and "cc-pVDZ" as the basis function. In this specification, the ionization energies of the decomposable gas and the alternative gas are calculated by a quantum mechanical calculation method using "B3LYP" as the density functional method and "cc-pVDZ" as the basis function to find the enthalpy of the ground state structure of the decomposable gas and the alternative gas (enthalpy when the charge is 0) and the enthalpy of the positively charged structure (enthalpy when the charge is +1), and are calculated by subtracting the enthalpy of the ground state structure from the enthalpy of the positively charged structure.

[0010] [2] In the quantitative analysis method for decomposable gases according to [1] above, it is preferable that the decomposable gases have a concentration change rate of 100 ppm / 30 days or more in a temperature environment of 5°C or higher and 300°C or lower.

[0011] [3] In the quantitative analysis method for decomposable gases according to [1] or [2] above, it is preferable that the discharge gas is at least one gas selected from the group consisting of helium, neon, argon, krypton, xenon, and nitrogen molecules.

[0012] [4] In the method for quantitatively analyzing decomposition gases according to any one of the above [1] to [3], the alternative gas is preferably a hydrocarbon.

[0013] According to the present invention, a method for quantitatively analyzing decomposable gases that is easy to operate and highly accurate can be provided.

[0014] 1 is a flow diagram showing an example of a method for quantitatively analyzing decomposable gases of the present invention; FIG. 2 is a schematic diagram showing an example of a gas chromatograph used in the method for quantitatively analyzing decomposable gases of the present invention; FIG. 3 is a graph showing the time-dependent change in the rate of change of C concentration in Example 1 and Comparative Example 1; FIG. 4 is a graph showing the time-dependent change in the rate of change of N concentration in Example 2 and Comparative Example 2; FIG. 5 is a graph showing the time-dependent change in the rate of change of P concentration in Example 3 and Comparative Example 3; and FIG. 6 is a graph showing the time-dependent change in the rate of change of Ge concentration in Example 4 and Comparative Example 4.

[0015] (Method for quantitatively analyzing decomposable gases) The method for quantitatively analyzing decomposable gases of the present invention (hereinafter sometimes simply referred to as "quantitative analysis method") is a method for quantitatively analyzing decomposable gases contained in a sample using a gas chromatograph equipped with a pulse discharge ionization detector (PPD). In the method for quantitatively analyzing decomposable gases of the present invention, before the sample is introduced into the gas chromatograph, the energy difference between the photon energy obtained by the emission of the discharge gas used in the pulse discharge ionization detector (hereinafter sometimes referred to as "emission energy") and the ionization energy of the decomposable gas is determined as ΔIE １ The energy difference between the emission energy and the ionization energy of the alternative gas is ΔIE ２ In this case, ΔIE １ and ΔIE ２ The pulse discharge ionization detector is calibrated using (selected from) an alternative gas (hereinafter, sometimes simply referred to as "alternative gas") whose difference from the standard gas is between -1 eV and 1 eV. The quantitative analysis method for decomposable gases as described above is excellent in operability and accuracy of quantitative analysis of decomposable gases. This is presumably because, in a gas chromatograph equipped with a pulse discharge ionization detector, there is a high correlation between peak area and ΔIE, so that a good calibration curve can be created even when the pulse discharge ionization detector is calibrated using an alternative gas.

[0016] <Gas Chromatograph> The gas chromatograph used in the quantitative analysis method of the present invention is not particularly limited as long as it is equipped with a pulse discharge ionization detector, and a conventionally known gas chromatograph can be used, for example, GC7890B (G3440B) manufactured by Agilent Technologies, Inc.

[0017] Here, the pulsed discharge ionization detector equipped in a gas chromatograph typically uses photons (photon energy) obtained by pulsed discharge of a discharge gas, such as helium, as the ionization energy source. To explain this in more detail, taking the case where the discharge gas is helium as an example, first, a pulsed high voltage is applied to the discharge gas introduced through the discharge gas inlet of the pulsed discharge ionization detector, and the helium is excited and dimerized by the pulsed discharge energy. The dimerized helium then releases photon energy as it returns to its original stable form, helium. This photon energy serves as the ionization energy source. The photon energy generated by the pulsed discharge then ionizes components (such as alternative gases and decomposition gases) effluent from the gas chromatograph column. The electrons generated by the ionization are collected by a bias electrode onto a collecting electrode, and the current is amplified by an amplifier and observed as a peak.

[0018] <Alternative Gas> In the quantitative analysis method of the present invention, the alternative gas is ΔIE １ and ΔIE ２ The difference between １ " - "ΔIE ２ It is necessary to use a substitute gas in which ΔIE is between -1 eV and 1 eV. By using such a substitute gas, the quantitative analysis method of the present invention can achieve high accuracy in quantitative analysis of decomposable gases. １ and ΔIE ２ The difference between these values ​​is preferably −0.5 eV or more and 0.5 eV or less, more preferably −0.3 eV or more and 0.3 eV or less, and even more preferably −0.1 eV or more and 0.1 eV or less.

[0019] Here, from the viewpoint of improving the accuracy of quantitative analysis of decomposable gases, it is preferable to use an alternative gas in which the energy difference between the ionization energy of the decomposable gas and the ionization energy of the alternative gas is −1 eV or more and 1 eV or less, more preferably −0.5 eV or more and 0.5 eV or less, even more preferably −0.3 eV or more and 0.3 eV or less, and even more preferably −0.1 eV or more and 0.1 eV or less.

[0020] In one embodiment, the alternative gas is not particularly limited, but preferably has a fragmentation rate of 50% or less, more preferably 40% or less, and even more preferably 30% or less. If the fragmentation rate of the alternative gas is equal to or less than the above upper limit, the accuracy of quantitative analysis of decomposable gases can be improved. In this specification, "fragmentation" refers to the decomposition of compounds constituting the alternative gas into lower molecular weight compounds. In this specification, the "fragmentation rate" can be measured using a gas chromatograph (so-called "GC-MS") equipped with a mass analyzer with an ionization energy set to 17 eV, and refers to the ratio of fragmented compounds to the total compounds before fragmentation.

[0021] As an alternative gas, ΔIE １ and ΔIE ２ There are no particular limitations as long as the difference between the ΔIE and ΔIE falls within the above-mentioned range, but examples include simple substances such as nitrogen molecules, oxygen molecules, and hydrogen molecules; compounds such as hydrocarbons; etc. Among these, from the viewpoint of being easy to handle and improving the operability of quantitative analysis of decomposition gases, and ２ Hydrocarbons are preferred from the viewpoint of improving the accuracy of quantitative analysis of decomposition gases, since there is a high correlation between the peak area in a pulse discharge ionization detector and the amount of carbon monoxide present.

[0022] In this specification, a hydrocarbon is a compound consisting of carbon and hydrogen atoms and typically does not contain any atoms other than carbon and hydrogen atoms. Suitable examples of such hydrocarbons include hydrocarbons having 1 to 8 carbon atoms. Examples of hydrocarbons having 1 carbon atom include methane. Examples of hydrocarbons having 2 carbon atoms include ethane, ethylene, and acetylene. Examples of hydrocarbons having 3 carbon atoms include propane, propylene, and cyclopropane. Examples of hydrocarbons having 4 carbon atoms include n-butane, isobutane, 1-butene, 2-butene, 2-butene, and 1,3-butadiene. Examples of hydrocarbons having 5 carbon atoms include n-pentane, isopentane, and neopentane. Examples of hydrocarbons having 6 carbon atoms include hydrocarbons having 5 carbon atoms, such as n-hexane, 2-methylpentane, cyclohexane, 1-hexene, and benzene. Examples of hydrocarbons with seven carbon atoms include n-heptane, 2-methylhexane, 1-heptene, and toluene. Examples of hydrocarbons with eight carbon atoms include n-octane, 3,4-dimethylhexane, 2,2,4-trimethylpentane, 1-octene, o-xylene, m-xylene, p-xylene, and styrene. Among the above hydrocarbons, from the viewpoint of further improving the operability of quantitative analysis of decomposition gases and reducing ΔIE ２ In view of the higher correlation between the peak area in a pulse discharge ionization detector and the concentration of toluene, and the improved accuracy of quantitative analysis of decomposable gases, n-butane, n-pentane, benzene, toluene, and styrene are preferred. That is, it is preferable to use at least one compound selected from the group consisting of n-butane, n-pentane, benzene, toluene, and styrene as the alternative gas.

[0023] <Discharge Gas> The discharge gas is not particularly limited as long as it is excited by pulse discharge energy to emit photon energy. However, since it can easily emit photon energy, it is preferably at least one gas selected from the group consisting of helium, neon, argon, krypton, xenon, and nitrogen, and more preferably at least one gas of helium and argon.

[0024] In one embodiment, when the discharge gas is composed of one gas, the discharge gas is preferably helium, since helium has a high photon energy (approximately 17.7 eV), and if the discharge gas is helium, the obtained peak area can be increased, thereby improving the accuracy of quantitative analysis of decomposable gases.

[0025] In one embodiment, when the discharge gas is composed of two gases, the discharge gas is preferably a mixture of helium and argon. Since argon has a photon energy that is moderately lower than that of helium, using argon together with helium can effectively suppress fragmentation of alternative gases, decomposable gases, etc., thereby improving the accuracy of quantitative analysis of decomposable gases. When the discharge gas is a mixture of helium and argon, the photon energy may be, for example, 10.8 eV or more, or 11.3 eV or more, or, for example, 12.3 eV or less, or 12.8 eV or less.

[0026] <Decomposable Gas> The decomposable gas is not particularly limited as long as it is a gas with higher decomposability than the above-mentioned alternative gas. Specific examples of the decomposable gas include C ２ F ４ , C ４ F ８ , cyclo-C ５ F ８ Fluorocarbons such as B ２ H ６ , B ４ H １０ , B ５ H ９ , B ５ H １１ Boron hydrides (so-called boranes) such as NH ３ , N ２ H４ , N ３ N ６ Nitrogen hydrides such as Ge ２ H ６ Germanium hydrides such as PH ３ , P ２ H ４ However, since the quantitative analysis method of the decomposition gas of the present invention can more effectively demonstrate its effect, the decomposition gas is preferably C ２ F ４ , B ４ H １０ , B ５ H ９ , B ５ H １１ , N ２ H ４ , Ge ２ H ６ , and P ２ H ４ It is preferable that the decomposable gas is at least one compound selected from the group consisting of: In this specification, the decomposable gas may also include a reaction intermediate produced by decomposition or polymerization reaction of the decomposable gas.

[0027] In order for the quantitative analysis method of the present invention to effectively exhibit its effects, the decomposable gas preferably has a concentration change rate of 100 ppm / 30 days or more in a temperature environment of 5°C or higher and 300°C or lower. The concentration change rate is more preferably 1000 ppm / 30 days or higher, and even more preferably 5000 ppm / 30 days or higher. The concentration change rate is, for example, 20000 ppm / 30 days or less, or may be 15000 ppm / 30 days or less, or 10000 ppm / 30 days or less.

[0028] In one embodiment, the decomposable gas is not particularly limited, but preferably has a fragmentation rate of 50% or less, more preferably 40% or less, and even more preferably 30% or less. If the fragmentation rate of the decomposable gas is equal to or less than the upper limit, the accuracy of quantitative analysis of the decomposable gas can be improved.

[0029] The quantitative analysis method for decomposition gases of the present invention will be described below with reference to FIGS. 1 and 2, but the quantitative analysis method for decomposition gases of the present invention is not limited thereto.

[0030] Fig. 1 is a flow diagram showing an example of the quantitative analysis method for decomposable gases of the present invention. As shown in Fig. 1, the quantitative analysis method 10 includes a calibration step 11 in which a pulse discharge ionization detector is calibrated using (selecting) the predetermined alternative gas described above as a standard gas, an introduction step 12 in which a sample containing a decomposable gas is introduced into a gas chromatograph, a separation and detection step 13 in which the decomposable gas in the sample is separated and detected, and an analysis step 14 in which the quantitative value of the detected decomposable gas is analyzed. Note that the quantitative analysis method 10 may further include any steps other than the calibration step 11, the introduction step 12, the separation and detection step 13, and the analysis step 14.

[0031] Here, Figure 2 is a schematic diagram showing an example of a gas chromatograph used in the method for quantitatively analyzing decomposable gases of the present invention. The gas chromatograph 20 shown in Figure 2 includes a separation column 21, an oven 22 for heating the separation column 21, and a pulse discharge ionization detector 23 connected to the separation column 21. A carrier gas is supplied from path A, an alternative gas or a sample is supplied from path B, and a discharge gas is supplied from path C. The various supplied gases are then exhausted from exhaust section D as exhaust gas.

[0032] <Proofreading step> In the proofreading step, ΔIE １ and ΔIE ２ The pulse discharge ionization detector is calibrated using (selecting) an alternative gas as a standard gas whose difference from the peak area is between -1 eV and 1 eV. Specifically, a calibration curve showing the relationship between the concentration of the alternative gas and the peak area is created using the alternative gas.

[0033] <Introduction Step> In the introduction step, a sample containing a decomposable gas is introduced into a gas chromatograph. More specifically, the sample containing a decomposable gas is introduced into a column of the gas chromatograph.

[0034] In the introduction step, the amount of sample introduced into the gas chromatograph is not particularly limited and can be adjusted appropriately depending on the diameter and length of the gas chromatograph column, but is, for example, 0.1 mL or more and 5 mL or less.

[0035] In the separation and detection step, the decomposable gases in the sample are separated and detected. More specifically, the sample is passed through a column together with a carrier gas to separate the decomposable gases, and the separated decomposable gases are detected by a pulse discharge ionization detector.

[0036] In the separation and detection step, the carrier gas is not particularly limited, and an inert gas such as helium can be used.

[0037] In the separation and detection step, the carrier flow rate is not particularly limited and is, for example, 1 mL / min or more and 20 mL / min or less.

[0038] In the separation and detection step, the column temperature is not particularly limited and can be adjusted appropriately depending on the physical properties of the decomposable gas and the alternative gas, but is, for example, 20°C or higher and 100°C or lower.

[0039] In the separation and detection step, the temperature of the pulse discharge ionization detector is not particularly limited and can be adjusted appropriately depending on the physical properties of the decomposable gas and the alternative gas, but is, for example, 100°C or higher and 200°C or lower.

[0040] <Analysis Step> In the analysis step, the quantitative values ​​of the detected decomposition gases are analyzed. The analysis of the quantitative values ​​is not particularly limited, and can be performed using conventionally known analysis software or the like.

[0041] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples in any way.

[0042] <Gas chromatograph equipped with a pulse discharge ionization detector> In the following examples and comparative examples, a 7890B (G3440B) manufactured by Agilent Technologies was used as a gas chromatograph equipped with a pulse discharge ionization detector (PDD-GC). The measurement conditions were as follows. <Measurement conditions> Column: Restek Rtx-Volatiles 30 m x 0.32 mm x 1.5 μm Oven temperature: 40° C. Detector temperature: 150° C. Carrier gas: He (photon energy = approximately 17.7 eV) Carrier flow rate: 5 mL / min Detector: PDD Calibration tube: 0.25 mL

[0043] <Ionization Energy of Decomposable Gases and Alternative Gases> In the following examples and comparative examples, the ionization energies of the decomposable gases and alternative gases were calculated by quantum mechanical calculation using "B3LYP" as the density functional method and "cc-pVDZ" as the basis function, calculating the enthalpy of the ground state structure of the decomposable gases and alternative gases (enthalpy when the charge is 0) and the enthalpy of the positive charge structure (enthalpy when the charge is +1), and then subtracting the enthalpy of the ground state structure from the enthalpy of the positive charge structure.

[0044] <Fragmentation Rates of Decomposable Gases and Alternative Gases> In the following examples and comparative examples, the fragmentation rates of decomposable gases and alternative gases were measured using a gas chromatograph equipped with a mass analyzer under the following conditions. <Measurement Conditions> - Analytical device: JEOL gas chromatograph mass spectrometer JMS-Q1500GC (GC section is an 8890 GC system manufactured by Agilent Technologies) - Column: Restek Rtx-Volatiles 30 m × 0.32 mm × 1.5 μm - Carrier gas: He - Carrier gas flow rate: 10 ccm - Oven temperature: 40° C. - Ionization current: 20 μA - Ionization energy: 17 eV - Ion source temperature: 120° C. - Q-pole temperature: 70° C. - Sample flow rate: 100 ccm

[0045] <Fourier Transform Infrared Spectroscopy (FT-IR)> In the following examples and comparative examples, FT-IR measurements were performed using an FT / IR6600 manufactured by JASCO Corporation. The measurement conditions were as follows: <Measurement conditions> Gas flow rate: 100 sccm Window material: KBr Cell optical path length: 1 cm Detector: TGS (no attenuator, aperture diameter 7.1 mm) Pressure inside cell: 120 kPaA Measurement wavenumber range: 1000 to 3000 cm －１ ・Resolution: 4cm －１ Cell temperature: 35°C Number of integrations (background): 256 times Number of integrations (sample): 128 times (2 min 34 s) Measurement interval: 26 s Measurement time: 30 min

[0046] (Example 1) <Preparation of Sample> First, C ４ F ８ A sample consisting of C was prepared. ２ F ４ (Ionization energy: 9.57 eV, ΔIE １ Quantitative analysis was carried out using the decomposition gases: 8.13 eV, fragmentation rate: 25%).

[0047] <Calibration process> Benzene (ionization energy: 9.01 eV, ΔIE ２ The pulse discharge ionization detector was calibrated using benzene as a standard gas. Specifically, a calibration curve showing the relationship between the benzene concentration and the peak area was prepared. ２ F ４ ΔIE in (decomposition gas) and benzene (alternative gas) １ and ΔIE ２ The difference (8.13 eV - 8.69 eV) is -0.56 eV.

[0048] <Introduction Step> Next, the above sample was stored under conditions of about 290° C., and the sample on days 0, 30, 65, 92, 128, and 154 was introduced into the PDD-GC.

[0049] <Separation and Detection Step> Next, the sample is passed through the column together with a carrier gas to detect C２ F ４ and the separated C ２ F ４ was detected by a pulsed discharge ionization detector.

[0050] <Analysis step> Next, the detected C ２ F ４ The quantitative values ​​of C were analyzed using the obtained analytical results. ２ F ４ The carbon (C) concentration (hereinafter sometimes referred to as "C concentration") derived from the slag was calculated, and the C concentration on day 0 was calculated. ２ F ４ The C concentration of the origin was set as the standard (0 ppm), and the C concentration at each elapsed day was ２ F ４ The change in the C concentration derived from the sieving was calculated. The results are shown in Table 1.

[0051] <Confirmation of measurement accuracy> The above sample was measured by FT-IR on the 0th, 30th, 65th, 92nd, 128th, and 154th days. ４ F ８ The C concentration of the derived ４ F ８ The C concentration of the origin was set as the standard (0 ppm), and the C concentration at each elapsed day was ４ F ８ The change in the C concentration derived from the spores was calculated. The results are shown in Table 1. ２ F ４ Change in C concentration and C ４ F ８ The change in C concentration was calculated by the following formula (1) using the change in C concentration derived from the sample, and the measurement accuracy was confirmed. The closer the calculation result of formula (1) is to 100%, the higher the measurement accuracy is. The results are shown in Table 1. (1000000 + ("C ２ F ４ "Change in C concentration of origin" + "C ４ F ８ Change in C concentration derived from the carbon dioxide gas) / 1,000,000 × 100 [mass%] (1)

[0052]

[0053] (Comparative Example 1) C as an alternative gas ２ F ６(Ionization energy: 12.04 eV, ΔIE ２ The various operations, measurements, calculations and confirmations were carried out in the same manner as in Example 1, except that the C ２ F ４ and C ２ F ６ ΔIE in １ and ΔIE ２ The difference (8.13 eV - 5.66 eV) is 2.47 eV.

[0054]

[0055] Here, a graph showing the time course of the rate of change of the C concentration in Example 1 and Comparative Example 1 is shown in FIG.

[0056] As is clear from Tables 1 and 2 and Figure 3, the quantitative analysis method for decomposition gases in Example 1 has excellent measurement accuracy, as the rate of change in C concentration is close to 100% by mass. Furthermore, the quantitative analysis method for decomposition gases in Example 1 is easy to operate because it uses PDD-GC.

[0057] (Example 2) <Preparation of Sample> First, 10 mass % N ２ H ４ A sample consisting of 90% by mass of N and 90% by mass of He was prepared. ２ H ４ (Ionization energy: 7.52 eV, ΔIE １ Quantitative analysis was carried out using the energy of 10.18 eV and the fragmentation rate of 45%) as decomposition gases.

[0058] <Calibration process> Styrene (ionization energy: 8.03 eV, ΔIE ２ The pulse discharge ionization detector was calibrated using styrene as a standard gas. Specifically, a calibration curve showing the relationship between the styrene concentration and the peak area was prepared. ２ H ４ ΔIE in (decomposition gas) and styrene (alternative gas) １ and ΔIE ２ The difference (10.18 eV - 9.67 eV) is 0.51 eV.

[0059] <Introduction Step> Next, the above sample was stored under conditions of about 60° C., and the sample on days 0, 30, 65, 92, 128, and 154 was introduced into the PDD-GC.

[0060] <Separation and Detection Step> Next, the sample is passed through the column together with a carrier gas to detect N ２ H ４ and the separated N ２ H ４ was detected by a pulsed discharge ionization detector.

[0061] <Analysis step> Next, the detected N ２ H ４ The quantitative values ​​of N were analyzed using the obtained analytical results. ２ H ４ The carbon (N) concentration (hereinafter sometimes referred to as "N concentration") derived from the soil was calculated, and the N concentration on day 0 was calculated. ２ H ４ The N concentration of the origin was set as the standard (0 ppm), and the N concentration at each elapsed day was ２ H ４ The change in the nitrogen concentration derived from the soil was calculated. The results are shown in Table 3.

[0062] <Confirmation of measurement accuracy> The above sample was measured by FT-IR on the 0th, 30th, 65th, 92nd, 128th, and 154th days. ３ The N concentration of the origin was calculated, and the NH on day 0 was ３ The NH concentration at each elapsed day was set as the standard (0 ppm). ３ The change in the N concentration derived from the soil was calculated. The results are shown in Table 3. ２ H ４ Changes in N concentration and NH ３ The change in N concentration was calculated by the following formula (2) using the change in N concentration derived from the sample, and the measurement accuracy was confirmed. The closer the calculation result of formula (2) is to 100 mass%, the higher the measurement accuracy. The results are shown in Table 3. (100000 + ("N ２ H ４ Change in N concentration derived from ３ Change in N concentration derived from the sieve ")) / 100,000 × 100 [mass%] ... (2)

[0063]

[0064] (Comparative Example 2) NH as an alternative gas ３ (Ionization energy: 9.86 eV, ΔIE ２ The various operations, measurements, calculations, and confirmations were carried out in the same manner as in Example 2, except that the N ２ H ４ and N.H. ３ ΔIE in １ and ΔIE ２ The difference (10.18 eV - 7.84 eV) is 2.34 eV.

[0065]

[0066] FIG. 4 shows a graph of the change in the rate of change of the N concentration over time in Example 2 and Comparative Example 2.

[0067] As is clear from Tables 3 and 4 and Figure 4, the quantitative analysis method for decomposition gases in Example 2 has excellent measurement accuracy, as the rate of change in N concentration is close to 100% by mass. In addition, the quantitative analysis method for decomposition gases in Example 2 is easy to operate because it uses PDD-GC.

[0068] (Example 3) <Preparation of Sample> First, a 20% by weight pH ３ A sample consisting of 80 mass % of P and 80 mass % of He was prepared. ２ H ４ (Ionization energy: 8.64 eV, ΔIE １ Quantitative analysis was carried out using the decomposition gases (9.06 eV, fragmentation rate: 27%).

[0069] <Calibration process> Toluene (ionization energy: 8.53 eV, ΔIE ２ The pulse discharge ionization detector was calibrated using toluene as a standard gas. Specifically, a calibration curve showing the relationship between the toluene concentration and the peak area was prepared. ２ H ４ ΔIE in (decomposition gas) and toluene (alternative gas)１ and ΔIE ２ The difference (9.06 eV - 9.17 eV) is -0.11 eV.

[0070] <Introduction Step> Next, the above sample was stored under conditions of about 50° C., and the sample on days 0, 30, 65, 92, 128, and 154 was introduced into the PDD-GC.

[0071] <Separation and Detection Step> Next, the sample is passed through the column together with a carrier gas to detect P ２ H ４ and the separated P ２ H ４ was detected by a pulsed discharge ionization detector.

[0072] <Analysis step> Next, the detected P ２ H ４ The quantitative values ​​of P were analyzed. ２ H ４ The carbon (P) concentration (hereinafter sometimes referred to as "P concentration") derived from the soil was calculated, and the P concentration on day 0 was calculated. ２ H ４ The P concentration of the origin was set as the standard (0 ppm), and the P concentration at each elapsed day was ２ H ４ The change in the P concentration derived from the soil was calculated. The results are shown in Table 5.

[0073] <Confirmation of measurement accuracy> The above sample was measured by FT-IR on the 0th, 30th, 65th, 92nd, 128th, and 154th days to determine the pH. ３ The derived P concentration was calculated, and the pH on day 0 was ３ The pH at each elapsed day was determined based on the reference P concentration (0 ppm). ３ The change in the P concentration derived from the soil was calculated. The results are shown in Table 5. ２ H ４ Change in P concentration and pH ３ The change in the N concentration derived from the sample was used to calculate the change in the P concentration using the following formula (3), and the measurement accuracy was confirmed. The closer the calculation result of formula (3) is to 100 mass%, the higher the measurement accuracy. The results are shown in Table 3. (200000 + ("P ２ H ４ Change in P concentration derived from "+"３ Change in P concentration derived from the oxidized carbon dioxide) / 200,000 × 100 [mass%] (3)

[0074]

[0075] (Comparative Example 3) PH as an alternative gas ３ (Ionization energy: 9.77 eV, ΔIE ２ The various operations, measurements, calculations and confirmations were carried out in the same manner as in Example 3, except that the ion beam energy was 7.93 eV and the fragmentation rate was 35%). The results are shown in Table 6. ２ H ４ and PH ３ ΔIE in １ and ΔIE ２ The difference (9.06 eV - 7.93 eV) is 1.13 eV.

[0076]

[0077] FIG. 5 shows a graph of the change in the rate of change of the P concentration over time in Example 3 and Comparative Example 3.

[0078] As is clear from Tables 5 and 6 and Figure 5, the quantitative analysis method for decomposition gases in Example 3 has excellent measurement accuracy, as the rate of change in P concentration is close to 100% by mass. In addition, the quantitative analysis method for decomposition gases in Example 3 is easy to operate because it uses PDD-GC.

[0079] (Example 4) <Sample Preparation> First, Ge ２ H ６ A sample consisting of Ge was prepared. ２ H ６ (Ionization energy: 9.26 eV, ΔIE １ Quantitative analysis was carried out using the decomposition gas as the ion beam.

[0080] <Calibration process> Benzene (ionization energy: 9.01 eV, ΔIE ２ The pulse discharge ionization detector was calibrated using benzene as a standard gas. Specifically, a calibration curve showing the relationship between the benzene concentration and the peak area was created.２ H ６ ΔIE in (decomposition gas) and benzene (alternative gas) １ and ΔIE ２ The difference (8.44 eV - 8.69 eV) is -0.25 eV.

[0081] <Introduction Step> Next, the above samples were stored under conditions of about 40° C., and the samples on days 0, 30, 65, 92, 128, and 154 were introduced into the PDD-GC.

[0082] <Separation and Detection Step> Next, the sample is passed through the column together with a carrier gas to detect Ge. ２ H ６ The separated Ge ２ H ６ was detected by a pulsed discharge ionization detector.

[0083] <Analysis step> Next, the detected Ge ２ H ６ The quantitative values ​​of Ge were analyzed using the obtained analytical results. ２ H ６ The carbon (Ge) concentration (hereinafter sometimes referred to as "Ge concentration") derived from the sintered body was calculated, and the Ge concentration on day 0 was calculated. ２ H ６ The Ge concentration at each elapsed day was taken as the standard (0 ppm). ２ H ６ The change in the Ge concentration was calculated, and the results are shown in Table 7.

[0084] <Confirmation of measurement accuracy> The above samples were measured by FT-IR on the 0th, 30th, 65th, 92nd, 128th, and 154th days. ４ The concentration of Ge derived from the ion exchange reaction was calculated, and the concentration of GeH ４ The GeH concentration at each elapsed day was taken as the standard (0 ppm). ４ The change in the Ge concentration derived from the ion beam was calculated. The results are shown in Table 7. ２ H ６ The change in the Ge concentration and GeH ４The change in Ge concentration was calculated by the following formula (4) using the change in Ge concentration derived from the ion beam and the amount of change in Ge concentration from the ion beam. The measurement accuracy was confirmed. The closer the calculation result of formula (4) is to 100 mass %, the higher the measurement accuracy. The results are shown in Table 7. ２ H ６ "Change in Ge concentration from" + "GeH ４ Change in Ge concentration derived from SiO2 / 1,000,000 × 100 [mass%] (4)

[0085]

[0086] Comparative Example 4: GeH as an alternative gas ４ (Ionization energy: 11.16 eV, ΔIE ２ The various operations, measurements, calculations, and confirmations were carried out in the same manner as in Example 2, except that Ge was used. ２ H ６ and GeH ４ ΔIE in １ and ΔIE ２ The difference (8.44 eV - 6.54 eV) is 1.90 eV.

[0087]

[0088] FIG. 6 is a graph showing the time course of the rate of change of the Ge concentration in Example 4 and Comparative Example 4.

[0089] 6, the method for quantitatively analyzing decomposable gases in Example 4 has excellent measurement accuracy, since the rate of change in Ge concentration is close to 100% by mass. Furthermore, the method for quantitatively analyzing decomposable gases in Example 4 is easy to operate because it uses PDD-GC.

[0090] According to the present invention, a method for quantitatively analyzing decomposable gases that is easy to operate and highly accurate can be provided.

[0091] 10: Quantitative analysis method 11: Calibration step 12: Introduction step 13: Separation and detection step 14: Analysis step 20: Gas chromatograph 21: Separation column 22: Oven 23: Pulse discharge ionization detector

Claims

1. A method for quantitatively analyzing a decomposable gas contained in a sample using a gas chromatograph equipped with a pulse discharge ionization detector, comprising: before the sample is introduced into the gas chromatograph, determining the energy difference between the photon energy obtained by the emission of the discharge gas used in the pulse discharge ionization detector and the ionization energy of the decomposable gas as ΔIE １ The energy difference between the photon energy obtained by the emission of the discharge gas used in the pulse discharge ionization detector and the ionization energy of the alternative gas is defined as ΔIE ２ In this case, ΔIE １ and ΔIE ２ a substitute gas having a difference of -1 eV or more and 1 eV or less from the standard gas, and the pulse discharge ionization detector is calibrated using the substitute gas as a standard gas.

2. A method for quantitatively analyzing a decomposable gas as described in claim 1, wherein the decomposable gas has a concentration change rate of 100 ppm / 30 days or more in a temperature environment of 5°C or higher and 300°C or lower.

3. A method for quantitatively analyzing decomposable gases according to claim 1 or 2, wherein the discharge gas is at least one gas selected from the group consisting of helium, neon, argon, krypton, xenon and nitrogen molecules.

4. The method for quantitatively analyzing decomposition gases according to claim 1 or 2, wherein the alternative gas is a hydrocarbon.

Images