JP2018091728A - Odorant detection method, gas leakage detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide odorant detection method capable of detecting odorant even when the content of odorant in a measured gas is small.SOLUTION: The odorant detection method includes: an adsorption concentration step in which a gas to be measured containing odorant a combustion gas is introduced into adsorption/concentration means containing an adsorbent to allow the adsorbent to absorb the odorant to generate a concentrated gas containing the concentrated odorant by desorb the odorant from the adsorbent; and a detection step in which the concentrated gas containing the concentrated odorant is introduced into a gas chromatograph analyzer with mass spectrometer to detect the odorant in the gas to be measured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for detecting an odorant and a method for detecting a gas leak.

  Odorless combustion gases such as city gas, liquefied petroleum gas, and propane gas may cause fires and poisoning accidents if leaked from their supply pipes, etc. It is difficult to detect leakage from a supply pipe without using the like. Therefore, when a certain amount of odorless combustion gas leaks, it is supplied as a supply gas with an odorant added to the odorless combustion gas so that the gas leakage can be easily detected by human olfaction. ing.

  By the way, when performing maintenance of the above-described supply gas supply pipe, etc., the odorant is so thin that it cannot be identified by the sense of smell and is derived from a supply gas leaked from the supply pipe, for example, other than a supply pipe generated in nature In some cases, a rare gas that is unknown to be detected is detected by a gas detector or the like. In the case of supply gas leaked from the supply pipe, it is necessary to specify the leak point of the supply pipe and repair it in order to prevent the occurrence of an accident. is there.

  Therefore, in such a case, the detected gas is collected, the component analysis of the gas to be measured is performed using, for example, a high-concentration identification detector or a gas chromatograph, and the gas leaked from the combustion gas supply pipe Is identified.

  However, even if a high-concentration identification detector or the like is used, it is difficult to identify whether the supply gas is contained in the measurement gas when the concentration of the supply gas contained in the measurement gas is low. there were. For this reason, the detection method of the odorant which can detect an odorant was calculated | required also about the gas to be measured with little content of supply gas, ie, the gas to be measured with little content of odorant.

  Accordingly, in view of the problems of the above-described conventional technology, an aspect of the present invention provides a method for detecting an odorant that can detect the odorant even when the content of the odorant in the gas to be measured is small. For the purpose.

According to one aspect of the present invention, after the gas to be measured containing the odorant and the combustion gas is introduced into the adsorption / concentration means provided with the adsorbent, the odorant is adsorbed on the adsorbent. An adsorption concentration step of generating a concentrated gas in which the odorant is concentrated by desorbing the odorant from the adsorbent;
And a detection step of detecting the odorant in the gas to be measured by introducing a concentrated gas obtained by concentrating the odorant into a gas chromatograph analyzer with a mass spectrometer. .

  According to one embodiment of the present invention, it is possible to provide a method for detecting an odorant that can detect the odorant even when the content of the odorant in the gas to be measured is small.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the adsorption | suction and concentration means in Example 1 of this invention. The detection result of the gas chromatograph analyzer with a mass spectrometer in Example 1 of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.
[Detection method of odorant]
The detection method of the odorant of this embodiment can have the following processes.

The measurement gas containing the odorant and the combustion gas is introduced into the adsorption / concentration means equipped with the adsorbent, and after the odorant is adsorbed to the adsorbent, the odorant is desorbed from the adsorbent. And an adsorption concentration process for generating a concentrated gas in which the odorant is concentrated.
A detection step of introducing a concentrated gas obtained by concentrating an odorant into a gas chromatograph analyzer with a mass spectrometer and detecting the odorant in the gas to be measured.

  The inventor of the present invention diligently studied a method for detecting an odorant capable of detecting the odorant even when the content of the odorant in the gas to be measured is small. And, by concentrating the odorant in the gas to be measured and using a predetermined analyzer, it is found that the odorant can be easily detected even when the content of the odorant in the gas to be measured is small. Completed the invention. Hereinafter, each process of the detection method of the odorant of this embodiment is demonstrated concretely.

  First, the gas to be measured that is evaluated by the odorant detection method of the present embodiment can be supplied to the adsorption concentration step. In such a process, it is possible to reduce moisture contained in the gas to be measured and some impurities such as organic substances and concentrate the odorant. In the adsorption concentration step, a concentrated gas obtained by concentrating the odorant contained in the gas to be measured can be obtained by the adsorption / concentration means.

  As the adsorption / concentration means used in the adsorption / concentration step, for example, an adsorption / concentration means equipped with an adsorbent can be used. As the adsorption / concentration means provided with the adsorbent, for example, an adsorbent packed in a column having a tube shape (cylindrical shape) or the like can be used. The adsorbent used in this case can be arbitrarily selected according to the odorant to be detected, and is not particularly limited. For example, an adsorbent made of glass, an adsorbent made of resin, etc. Can be used.

  The adsorption / concentration means is not limited to one means, and a plurality of adsorption / concentration means can be used together. For example, a plurality of adsorption / concentration means including an adsorbent can be used in combination. In this case, for example, adsorption / concentration means including different adsorbents can be used in combination. Further, as an adsorption / concentration means, in addition to an adsorption / concentration means equipped with an adsorbent, an adsorption / concentration means not having one or more adsorbents, specifically, for example, a column not packed with an adsorbent Can also be used.

  In the adsorption / concentration means equipped with the adsorbent, for example, a part of the organic substance containing the odorant is adsorbed on the adsorbent, and then the part of the organic substance containing the adsorbed odorant is released. A concentrated gas obtained by concentrating some organic substances including the agent can be obtained.

  On the other hand, in the adsorption / concentration means not equipped with the adsorbent, for example, using the inner wall of the column, a part of the organic substance containing the odorant is adsorbed, and then the part of the organic substance containing the adsorbed odorant is removed. By desorption, a concentrated gas obtained by concentrating some organic substances including an odorant can be obtained.

  In any of the adsorption / concentration means having an adsorbent and the adsorption / concentration means not having an adsorbent, it is contained in the gas to be measured, and in the detection step described later, components that interfere with the detection of the odorant, such as moisture or Further, it is possible to reduce and remove the remaining impurities such as organic substances.

  When using a plurality of adsorption / concentration means, the plurality of adsorption / concentration means can be connected in series.

  For example, the adsorption / concentration means is an adsorption / concentration means equipped with an adsorbent, an adsorbent-containing column filled with an adsorbent, and an adsorption / concentration means not equipped with an adsorbent, packed with an adsorbent. It is possible to have a configuration in which no adsorbent-free column is connected in series. In addition, the order etc. which connect the adsorption / concentration means provided with the adsorbent and the adsorption / concentration means not provided with the adsorbent are not particularly limited, and can be arranged in any order.

  Further, the adsorption / concentration means provided with the adsorbent and the adsorption / concentration means not provided with the adsorbent can be provided in plural for either one or both. For this reason, the adsorption / concentration means can have, for example, two or more adsorbent-containing columns and two or more adsorbent-free columns.

  For example, when two adsorbent-containing columns are included, a first adsorbent-containing column and a second adsorbent-containing column are connected in series, and the first adsorbent-containing column contains a part of the odorant. The concentrated gas obtained by adsorbing and concentrating the substance can be supplied to the second adsorbent-containing column. Further, even in the second adsorbent-containing column, a part of the organic substance containing the odorant is adsorbed and concentrated, whereby a concentrated gas obtained by further concentrating the odorant can be obtained. The concentrated gas concentrated in the second adsorbent-containing column is further supplied to one or more adsorbent-free columns, and is contained in the concentrated gas supplied from the second adsorbent-containing column in the adsorbent-free column. The odorant to be added can be further concentrated.

  The specific operation for adsorbing the odorant on the adsorbent or the inner wall of the column and concentrating the odorant is not particularly limited. For example, by supplying the adsorbent or the gas to be measured while cooling the column, or the concentrated gas from the upstream adsorption / concentration means, the adsorbent or the odorant in the gas to be measured is applied to the inner wall of the column. Some organic substances can be adsorbed. For example, while heating the adsorbent or the column, supplying the adsorbent or a carrier gas such as helium to the column releases some organic substances including the adsorbent and the odorant adsorbed on the inner wall of the column. The concentrated gas in which the odorant is concentrated can be generated. Note that the adsorbent, column cooling temperature, and heating temperature can be arbitrarily selected depending on the type of adsorbent used, the type of some organic components including odorant to be separated and concentrated from the gas to be measured, etc. It can be selected and is not particularly limited. Further, as described above, when a plurality of adsorption / concentration means are provided, it is preferable that each of the adsorption / concentration means is configured to control the cooling temperature and the heating temperature.

  When adsorbing and concentrating some components in the gas to be measured using an adsorbent, in order to remove impurities before adsorbing after adsorbing a part of the gas to be measured to the adsorbent, In general, a sweep gas such as helium is supplied to the adsorbent to perform a sweep purge. However, the detection method of the odorant according to the present embodiment is a method that can detect the odorant even when the measurement target gas contains only a very small amount of the odorant. For this reason, when the sweep purge is performed, a very small amount of the odorant adsorbed by the adsorbent is also reduced, which may make it difficult to detect the odorant.

  Therefore, in the adsorption concentration step of the detection method of the odorant of the present embodiment, the gas to be measured is introduced into the adsorption / concentration means equipped with the adsorbent, and the odorant is adsorbed to the adsorbent, and then continued. It is preferable to desorb the odorant from the adsorbent. More specifically, after the odorant is adsorbed to the adsorbent, the odorant is desorbed from the adsorbent without supplying a sweep gas to the adsorbent, that is, without performing a sweep purge. Is preferred. By not performing the sweep purge, it is possible to suppress a decrease in the content of the odorant in the concentrated gas and to prevent an increase in the lower limit of the detection limit of the odorant. It should be noted that by not performing the sweep purge, the contaminated component in the concentrated gas may increase, and depending on the contaminated component, a peak may occur in the vicinity of the odorant in the detection step. In such a case, for example, as described later, in a gas chromatograph analyzer with a mass spectrometer, by using the SIM mode, an adverse effect due to an increase in contaminant components can be suppressed.

  The concentrated gas obtained by concentrating the odorant in the adsorption concentration process can be used for the detection process.

  In the detection step, the concentrated gas generated in the adsorption concentration step is supplied to a gas chromatograph analyzer with a mass spectrometer (hereinafter also simply referred to as “GC / MS”) to detect an odorant in the gas to be measured. be able to.

  Analytical conditions in GC / MS are not particularly limited. However, according to the detection method of the odorant of this embodiment, the odorant is included even when the odorant is contained in the measured gas only in a very small amount. Is preferably detectable. For this reason, it is preferable that GC / MS performs measurement using the SIM mode (Selected Ion Monitoring mode) so that the odorant can be measured with high sensitivity.

  As a measurement mode in GC / MS, a scan mode (sometimes referred to as a TIC mode: Total Ion Chromatogram mode) and a SIM mode are exemplified. The scan mode is a mode in which the mass spectrum is measured by continuously changing the U voltage and the V voltage applied to the rod of the mass spectrometer. On the other hand, the SIM mode is a mode in which the mass spectrometer measures only a designated mass. Although the mass spectrum is not obtained in the SIM mode, the measurement is performed with respect to a specific mass, so that the measurement can be performed with higher sensitivity than in the scan mode.

  In the GC / MS, when the measurement is performed using the SIM mode, the mass spectrometer measures only the designated mass as described above. Therefore, for example, it is preferable to supply an odorant presumed to be contained in the gas to be measured in advance to the GC / MS and confirm the mass of the observed peak. When detecting the odorant for the gas to be measured, it is possible to specify the mass of the observed peak that has been examined in advance for the odorant and perform the measurement in the SIM mode.

  It does not specifically limit about the odorant and combustion gas which are contained in the to-be-measured gas supplied to the detection method of the odorant of this embodiment. Examples of the combustion gas include one or more selected from various combustible gases such as city gas, propane gas, liquefied petroleum gas, and hydrogen gas. Examples of the odorant include various odorants used in the above-described combustion gas. Specific examples of the odorant include one or more selected from tertiary butyl mercaptan, tetrahydrothiophene, dimethyl sulfide, ethyl mercaptan, cyclohexene, 5-ethylidene-2-norbornene, 2-alkyl-3-alkoxypyrazine and the like. Can be mentioned.

  In particular, gas pipes are installed at various locations to supply city gas to each consumer. And since it is requested | required that the leakage from this gas piping should be prevented especially, the detection method of the odorant of this embodiment can be used especially suitably, when combustion gas is city gas. Further, for example, cyclohexene and tertiary butyl mercaptan are used as odorants in city gas, and in recent years, the use of cyclohexene has increased.

  Therefore, the odorant contained in the gas to be measured to which the odorant detection method of the present embodiment is applied is preferably at least one selected from cyclohexene and tertiary butyl mercaptan. More preferably.

  The content of the odorant contained in the gas to be measured used in the detection method of the odorant of the present embodiment is not particularly limited, but it is preferably 10 ppt or more so that it can be reliably detected, for example. More preferably, it is 30 ppt or more.

Although the odorant detection method of this embodiment has been described above, according to the odorant detection method of this embodiment, an adsorption concentration process for concentrating the odorant in the gas to be measured, and an adsorption concentration process Because it has a detection process for analyzing the concentrated gas enriched with the odorant by GC / MS, it can be easily attached even from the gas to be measured, which has been difficult to detect in the past and has a low odorant content. Odorant can be detected [Gas leak detection method]
Next, a configuration example of the gas leak detection method of the present embodiment will be described.

  The gas leak detection method of the present embodiment is a gas leak detection method for detecting a gas leak of a supply gas containing an odorant and a combustion gas, and can include the following steps.

A gas to be measured that is suspected of containing a supply gas is introduced into an adsorption / concentration means equipped with an adsorbent, and a part of the gas to be measured is adsorbed on the adsorbent and then adsorbed from the adsorbent. Adsorption concentration step of generating a concentrated gas obtained by concentrating a part of the gas to be measured by desorbing a part of the gas.
A detection step of introducing a concentrated gas obtained by concentrating a part of the gas to be measured into a gas chromatograph analyzer with a mass spectrometer and detecting the presence or absence of an odorant in the gas to be measured.
A determination step of determining the presence or absence of gas leakage of the supply gas based on the result of the detection step.

  In the gas leak detection method according to the present embodiment, the gas to be measured which is suspected of containing the supply gas containing the odorant and the combustion gas, specifically, for example, collected around a pipe or the like suspected of gas leak About the gas which did, it can detect the presence or absence of an odorant by using for the following processes, and can determine and detect the presence or absence of a gas leak.

  Each step will be described below.

  First, the gas to be measured that is evaluated by the gas leak detection method of the present embodiment can be supplied to the adsorption concentration step. In the adsorption concentration step, it is possible to separate moisture components contained in the gas to be measured and some components such as organic substances from the gas to be measured, and to concentrate a part of the gas to be measured. When the gas to be measured includes a supply gas containing an odorant and a combustion gas, the odorant is used in the adsorption concentration step as in the case of the detection method for the odorant described above. It can be concentrated.

  In the adsorption concentration process, for example, an adsorption / concentration means equipped with an adsorbent can be used as the adsorption / concentration means. Further, in addition to the adsorption / concentration means provided with the adsorbent, an adsorption / concentration means not having an adsorbent can also be used.

  The configuration and specific operation conditions of the adsorption / concentration means used in the adsorption / concentration step are not particularly limited, and for example, the same adsorption / concentration means as in the above-described odorant detection method is used. Therefore, the description is omitted here.

  And the gas leak detection method of this embodiment is a method that can detect the odorant and detect the gas leak even when the gas to be measured contains only a very small amount of the odorant, for example. It is. For this reason, in the gas leak detection method of the present embodiment, as in the case of the odorant detection method described above, in the adsorption concentration step, the gas to be measured is introduced into the adsorption / concentration means equipped with the adsorbent. It is preferable that a part of the measurement gas adsorbed from the adsorbent is subsequently desorbed after adsorbing a part of the measurement gas on the adsorbent. More specifically, after a part of the gas to be measured is adsorbed to the adsorbent, the target to be adsorbed from the adsorbent without supplying a sweep gas to the adsorbent, that is, without performing a sweep purge. It is preferable to desorb a part of the gas. By not performing the sweep purge, it is possible to suppress a decrease in the content of part of the gas to be measured, which is the component to be detected in the concentrated gas, for example, the odorant, and to increase the lower limit of the detection limit of the component to be detected. Can be prevented. Note that, by not performing the sweep purge, there may be an increase in contaminant components in the concentrated gas, and depending on the contaminant components, for example, a peak of contaminant components may occur in the vicinity of the peak of the odorant in the detection step. In such a case, in the detection step described later, in the gas chromatograph analyzer with a mass spectrometer, by performing measurement using the SIM mode, it is possible to suppress adverse effects due to an increase in contaminant components.

  The concentrated gas obtained by concentrating a part of the gas to be measured in the adsorption concentration process can be used for the detection process.

  In the detection step, the concentrated gas generated in the adsorption concentration step can be supplied to a gas chromatograph analyzer with a mass spectrometer, and the presence or absence of an odorant in the gas to be measured can be detected.

  The analysis conditions in GC / MS are not particularly limited, and can be configured in the same manner as described in the odorant detection method described above, for example. For this reason, description about the analysis conditions in GC / MS is abbreviate | omitted.

  When measuring in SIM mode, supply the odorant contained in the supply gas suspected of being contained in the gas to be measured to GC / MS in advance and check the mass of the observed peak. It is preferable to keep it. And when detecting about to-be-measured gas, the mass of the observed peak investigated beforehand about an odorant can be specified, and a measurement can be implemented by SIM mode.

  And the gas leak detection method of this embodiment can further have the determination process which determines the presence or absence of the gas leak of supply gas based on the result (detection result) of a detection process.

  Specifically, when no odorant is detected in the detection step, it means that the gas to be measured did not contain the supply gas. Then, it can be determined that there is no gas leakage from the supply gas piping.

  On the other hand, when the odorant is detected in the detection step, it means that the gas to be measured contains the supply gas. Therefore, in the determination step, from the supply gas pipe around the place where the gas to be measured is collected. It can be determined that a gas leak has occurred. In the determination step, when it is determined that a gas leak has occurred from the supply gas piping, the supply gas piping can be arranged to block the gas leakage.

  Note that the gas to be measured used in the gas leak detection method of the present embodiment may contain the odorant and combustion gas in the supply gas, which are not particularly limited. For example, in the odorant detection method described above, The component similar to the illustrated odorant and combustion gas is mentioned.

  Although the gas leak detection method of the present embodiment has been described above, according to the gas leak detection method of the present embodiment, an adsorption concentration process for concentrating a part of the gas to be measured, and the measurement gas in the adsorption concentration process. Since it has a detection process of analyzing a part of the concentrated gas by GC / MS, even if the content of the odorant in the collected gas to be measured is small, the odorant is removed. It is possible to detect and more accurately determine the presence or absence of gas leakage.

Specific examples will be described below, but the present invention is not limited to these examples.
[Example 1]
The odorant in the gas to be measured containing the odorant and the combustion gas was detected by the following procedure.

  As the gas to be measured, a mixed gas comprising a combustion gas and an odorant, the combustion gas being a city gas, and the odorant component containing cyclohexene was prepared. The gas to be measured was prepared so that the content of cyclohexene in the gas to be measured was 0.01 ppb.

  Then, the gas to be measured was introduced into the adsorption / concentration means, and an adsorption / concentration step for producing a concentrated gas in which the odorant was concentrated was performed.

  A schematic diagram of the adsorption / concentration means 10 used is shown in FIG. FIG. 1 shows a cross-sectional view in a plane parallel to the length direction of the column and passing through the center portion of the column so that the configuration of the adsorption / concentration means 10 can be understood. As shown in FIG. 1, the adsorption / concentration means 10 does not have an adsorbent, and the first adsorbent-containing column 11 and the second adsorbent-containing column 12, which are adsorption / concentration means provided with an adsorbent. An adsorbent-free column 13 as an adsorbing / concentrating means is connected in series in that order. The first adsorbent-containing column 11, the second adsorbent-containing column 12, and the adsorbent-free column 13 are provided with heaters 21, 22, 23 and cooling means 31, 32, 33 around each column. It can be heated and cooled.

  The first adsorbent-containing column 11 has a configuration in which glass beads are filled as an adsorbent 111 in a column whose inner surface has been subjected to an inactivation treatment.

  The second adsorbent-containing column 12 has a configuration in which a bead made of resin is packed as an adsorbent 121 in a column whose inner surface is subjected to an inactivation treatment.

  The columns used for the first adsorbent-containing column 11, the second adsorbent-containing column 12, and the adsorbent-free column 13 all have a tube shape with an inner diameter of about 2 mm.

  In the adsorption concentration step, first, 100 cc of the gas to be measured is connected to the second adsorbent-containing column 12 of the first adsorbent-containing column 11 cooled to −50 ° C. by the cooling means 31 as indicated by the arrow A. Not fed to the end 11A. With this operation, a part of the organic substance including the odorant contained in the measurement gas was adsorbed on the adsorbent 111 in the first adsorbent-containing column 11. When supplying the gas to be measured to the first adsorbent-containing column 11, the valve 141 provided on the pipe 14 connecting the first adsorbent-containing column 11 and the second adsorbent-containing column 12 is closed, and the valve 142 is opened so that the gas to be measured does not flow into the second adsorbent-containing column 12.

  After the adsorbent 111 in the first adsorbent-containing column 11 has adsorbed a part of the organic substance including the odorant, that is, without performing the sweep purge, the first adsorbent-containing column 11 is moved to the heater 21. The helium gas was supplied to the first adsorbent-containing column 11 from the end portion 11A. With this operation, a part of the organic substance containing the odorant adsorbed on the adsorbent 111 was desorbed and supplied to the second adsorbent-containing column 12. At this time, the valve 141 provided on the pipe 14 is opened, and the valve 142 and the valve 143 are closed. Further, the valve 151 on the pipe 15 connecting the second adsorbent-containing column 12 and the adsorbent-free column 13 is closed, the valve 152 is opened, and the adsorbent-free column 13 is connected to the first adsorbent-containing column 13. Some organic substances including odorants from 11 were prevented from flowing.

  The second adsorbent-containing column 12 is previously cooled to −80 ° C. by the cooling means 32, and a part of the organic substance including the odorant supplied from the first adsorbent-containing column 11 is adsorbed. did. Subsequently, the second adsorbent-containing column 12 is heated to 180 ° C. by the heater 22 without performing a sweep purge, and a valve 143 connected to one end 12A of the second adsorbent-containing column 12 is provided. From the pipe, the valve 143 was opened and helium gas was supplied to desorb some organic substances including the odorant adsorbed on the adsorbent 121 and supplied to the adsorbent-free column 13. At this time, the valve 141 provided on the pipe 14 was closed, the valve 151 provided on the pipe 15 was opened, and the valves 152 and 153 were closed.

  The adsorbent-free column 13 was previously cooled to −160 ° C. by the cooling means 33, and a part of the organic substance containing the odorant supplied from the second adsorbent-containing column 12 was adsorbed on the tube wall. Continuously, that is, without performing a sweep purge, the adsorbent-free column 13 is instantaneously heated to 80 ° C. by the heater 23, and a valve 153 connected to one end 13A of the adsorbent-free column 13 is also provided. By opening the valve 153 from the pipe and supplying helium gas, a part of the organic substance containing the odorant adsorbed on the pipe wall is desorbed, and the other end 13B of the adsorbent-free column 13 is removed. GC / MS (Agilent model: Agilent GC7890A) (not shown) connected to the PC. At this time, the valve 151 provided on the pipe 15 was closed.

  As described above, the adsorption / concentration means 10 produced a concentrated gas obtained by concentrating the odorant contained in the gas to be measured (adsorption / concentration step).

  Next, the concentrated gas obtained in the adsorption concentration process was supplied to GC / MS as described above, and the detection process was performed.

  Here, in the GC / MS gas chromatograph section, Inert Cap 1MS (column inner diameter is 0.32 mm, length is 60 m) manufactured by GL Science Co., Ltd. is installed as a separation column. Then, after maintaining at an initial temperature of 35 ° C. for 4 minutes, the temperature was set to 280 ° C. under the condition of 10 ° C./min. Further, helium was used as the carrier gas, and the flow rate was set to 1 cc / min. Then, cyclohexene was supplied in advance to GC / MS, and it was confirmed by a mass spectrometer that peaks occurred at mass numbers of 54, 67, and 82. For this reason, in the mass spectrometer unit, 54, 67, and 82 were set as mass numbers, and the integration time was set to 100 ms so that the analysis was performed in the SIM mode.

  Then, the concentrated gas obtained in the above-described adsorption concentration step is introduced into the GC / MS having the above settings, and the odorant in the gas to be measured is detected. As shown in FIG. A clear peak X was detected in 67 spectra, and an odorant was detected (detection step).

As described above, it was confirmed that the odorant contained in the measured gas at a low concentration of 0.01 ppb could be detected.
[Comparative Example 1]
As in Example 1, a gas to be measured was prepared, which was composed of a combustion gas and an odorant, the combustion gas was a city gas, and the odorant was cyclohexene. The gas to be measured was prepared so that the cyclohexene content in the gas to be measured was 0.01 ppb as in Example 1.

  2 cc of the gas to be measured was supplied to a gas chromatograph (GL Science Co., Ltd. model: GC4000 / FID) equipped with an FID detector, and it was evaluated whether or not an odorant was contained.

  In the gas chromatograph, Inert Cap 1 (column inner diameter is 0.53 mm, length is 30 m) manufactured by GL Science Co., Ltd. is installed as a column, and the temperature condition of the oven part is an initial temperature of 40 ° C. for 5 minutes. After holding, the temperature was set to 190 ° C. under the condition of 5 ° C./min. Helium was used as the carrier gas, and the flow rate was 5 cc / min.

  However, no peak corresponding to cyclohexene could be confirmed, and no odorant could be detected.

10 Adsorption / concentration means 111, 121 Adsorbent

Claims (4)

A gas to be measured containing an odorant and a combustion gas is introduced into an adsorption / concentration means equipped with an adsorbent, and the odorant is adsorbed to the adsorbent, and then the odorant from the adsorbent. Adsorbing and concentrating step for producing a concentrated gas enriched with the odorant by desorbing
A detection method for detecting an odorant in the gas to be measured by introducing a concentrated gas obtained by concentrating the odorant into a gas chromatograph analyzer equipped with a mass spectrometer.   The method for detecting an odorant according to claim 1, wherein the odorant is cyclohexene.   The odorant detection method according to claim 1, wherein the gas chromatograph analyzer with a mass spectrometer performs measurement using a SIM mode. A gas leak detection method for detecting a gas leak of a supply gas containing an odorant and a combustion gas,
A gas to be measured that is suspected of containing the supply gas is introduced into an adsorption / concentration means equipped with an adsorbent, and a part of the gas to be measured is adsorbed to the adsorbent, and then adsorbed from the adsorbent. An adsorption concentration step of generating a concentrated gas obtained by concentrating a part of the measured gas by desorbing a part of the measured gas.
A detection step of introducing a concentrated gas obtained by concentrating a part of the gas to be measured into a gas chromatograph analyzer with a mass spectrometer, and detecting the presence or absence of the odorant in the gas to be measured;
A determination step of determining whether or not the supply gas has leaked based on a result of the detection step.

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