JP7352956B2 - mass spectrometry system - Google Patents

Description

The present invention relates to a mass spectrometry system that analyzes the mass of a component of a gas to be detected.

Conventional mass spectrometry systems are known to mix a reference substance with a known mass with the substance to be detected in order to correct the detected mass, and then analyze the mass (for example, (See Patent Document 1.)

Japanese Patent Application Publication No. 2015-121500

However, in conventional mass spectrometry systems, there is a problem in that it is necessary to mix a reference substance with the substance to be detected.

Therefore, an object of the present invention is to provide a mass spectrometry system that can improve convenience.

The mass spectrometry system of the present invention is a mass spectrometry system that ionizes and analyzes the mass of a component gas that is a component gas of a sample gas, and includes a measurement control unit that controls measurement by the mass spectrometry system; A reference gas determining section that determines a reference gas that is a reference gas for correcting the measured value of the mass of the detected component gas; and a measured value correcting section that executes the correction; A plurality of the measurements are performed to ionize the component gases with different energies, and the reference gas determining unit determines the measurement value, an ideal value of the mass of a reference gas candidate that is a candidate for the reference gas, and the plurality of measurements. A plurality of reference gases having mutually different masses are determined from the plurality of component gases detected in the measurement based on detection status information indicating in which of the component gases the component gas was detected, and the measured value is corrected. The unit is characterized in that the correction is performed based on the relationship between the ideal value and the measured value of the masses of the plurality of reference gases determined by the reference gas determination unit.

With this configuration, the mass spectrometry system of the present invention uses the component gas itself of the sample gas as a reference gas for correcting the measured value of the mass of the component gas detected in the measurement. There is no need to use it for correction, and convenience can be improved.

The mass spectrometry system of the present invention includes a component type specifying section that specifies the type of the component gas, and the component type specifying section specifies a component gas that indicates the ideal value of the mass of a component gas candidate that is a candidate for the component gas. In the candidate information, when there are a plurality of component gas candidates that are associated with the ideal value that is the same as the measurement value after the correction is performed by the measurement value correction unit, Based on each ionization energy and the detection status information, it may be specified which of the plurality of component gas candidates the component gas corresponds to.

With this configuration, the mass spectrometry system of the present invention can detect multiple component gas candidates when the component gas candidate information is associated with the same ideal value as the measured value after correction. Since it is specified which of the plurality of component gas candidates the component gas corresponds to based on the ionization energy of each candidate and the detection status information, the accuracy of identifying the component gas can be improved.

The mass spectrometry system of the present invention can improve convenience.

1 is a configuration diagram of a mass spectrometry system according to an embodiment of the present invention. 2 is a block diagram of the computer shown in FIG. 1. FIG. FIG. 3 is a diagram showing an example of a component gas candidate dictionary shown in FIG. 2; (a) A diagram showing the correspondence between the mass of each component gas of a specific sample gas measured by the mass spectrometry system shown in FIG. 1 and ionization energy. (b) A mass spectrum obtained by corona discharge measurement for the sample gas shown in FIG. 4(a). (c) A mass spectrum obtained by measuring 9.8 eV for the sample gas shown in FIG. 4(a). 2 is a timing chart of the operation of the mass spectrometry system shown in FIG. 1 when performing a measurement. 6 is a diagram showing an example of measurement results obtained by the operation shown in FIG. 5. FIG. 2 is a flowchart of the operation of the mass spectrometry system shown in FIG. 1 when identifying the type of component gas of a sample gas. 8 is a flowchart of part of the reference gas determination process shown in FIG. 7. FIG. 9 is a flowchart that is a continuation of the flowchart shown in FIG. 8. (a) It is an explanatory diagram of the mass correction process shown in FIG. 7 when the measured value of the mass of the first reference gas is smaller than the ideal value and the measured value of the mass of the second reference gas is larger than the ideal value. . (b) It is an explanatory diagram of the mass correction process shown in FIG. 7 when the measured value of the mass of the first reference gas is larger than the ideal value and the measured value of the mass of the second reference gas is also larger than the ideal value. . (c) It is an explanatory diagram of the mass correction process shown in FIG. 7 when the measured value of the mass of the first reference gas is smaller than the ideal value and the measured value of the mass of the second reference gas is also smaller than the ideal value. . (d) It is an explanatory diagram of the mass correction process shown in FIG. 7 when the measured value of the mass of the first reference gas is larger than the ideal value and the measured value of the mass of the second reference gas is smaller than the ideal value. . FIG. 7 is a diagram showing an example of the measurement results shown in FIG. 6 to which measurement values after execution of correction are added. 8 is a flowchart of the component type identification process shown in FIG. 7. FIG. FIG. 12 is a diagram showing an example of the measurement results shown in FIG. 11 with an ID added. FIG. 1 is a configuration diagram of a mass spectrometry system according to an embodiment of the present invention, which includes three types of energy generating units.

Embodiments of the present invention will be described below with reference to the drawings.

First, the configuration of the mass spectrometry system according to this embodiment will be explained.

FIG. 1 is a configuration diagram of a mass spectrometry system 10 according to this embodiment.

As shown in FIG. 1, the mass spectrometry system 10 includes an ionization section 20 that ionizes a gas that is a component of a sample gas that is a gas to be analyzed (hereinafter referred to as "component gas"); An ion separation unit 30 that separates ions by mass, an ion detection unit 40 that detects ions separated by the ion separation unit 30, and a computer 50 such as a PC (Personal Computer) that controls the operation of the mass spectrometry system 10. We are prepared.

The ionization section 20 is formed with an ionization chamber 21 for ionizing sample gas. The ionization chamber 21 includes a sample gas inlet 21a through which a sample gas is introduced, a sample gas outlet 21b through which the sample gas is discharged, and an ion exhaust port 21c through which ions of component gases of the sample gas are discharged. There is. A sample gas is introduced into the ionization chamber 21 from the sample gas inlet 21a under atmospheric pressure.

The ionization section 20 includes a suction pump 22 for sucking sample gas into the ionization chamber 21 . The suction pump 22 sucks sample gas from inside the ionization chamber 21 through the sample gas outlet 21b of the ionization chamber 21, and discharges the sucked sample gas to the outside of the ionization chamber 21.

The ionization section 20 includes a corona discharge section 23a as an energy generation section that generates energy of 12 eV or more, such as 15 eV, and a UV lamp (hereinafter referred to as "UV lamp") as an energy generation section that generates energy of 9.8 eV. ) 23b. A corona discharge section 23a and a UV lamp (9.8 eV) 23b are arranged within the ionization chamber 21.

In addition, below, the measurement when the component gas of a sample gas is ionized by the corona discharge part 23a is called a corona discharge measurement. Furthermore, the measurement when the component gas of the sample gas is ionized by the UV lamp (9.8 eV) 23b is referred to as 9.8 eV measurement.

The ionization section 20 includes a switching control section 24 that switches the energy generation section to be used.

The ion separation section 30 includes a chamber 31 into which ions are introduced from the ion outlet 21c of the ionization chamber 21.

The ion separation unit 30 includes a vacuum pump 32 that evacuates the inside of the chamber 31 . The vacuum pump 32 sucks gas from inside the chamber 31 and discharges the sucked gas outside the chamber 31.

The ion separation unit 30 extracts ions from the ionization chamber 21 into the chamber 31 through the ion discharge port 21c of the ionization chamber 21, and supplies power to the extraction electrode 33 that accelerates the extracted ions, and the extraction electrode 33. It includes a power source 34 that can change the voltage of the power supplied to the extraction electrode 33, and a scanning voltage control section 35 that continuously scans the voltage of the power source 34. The extraction electrode 33 is placed inside the chamber 31 .

Note that the measured value of the mass of the component gas detected by the measurement by the mass spectrometry system 10 deviates from the ideal value, so it needs to be corrected. The main reason for this deviation is that there is a deviation between the designed ideal value of the voltage of the power supply 34 and the actual voltage value of the power supply 34.

The ion separation unit 30 includes a magnet 36 that generates a magnetic field for bending the trajectory of ions accelerated by the extraction electrode 33. Magnet 36 is placed within chamber 31 .

The ion detection section 40 includes a Faraday cup 41 that detects the number of ions that have entered the ion detection section 40 as a current. Faraday cup 41 is placed within chamber 31 .

FIG. 2 is a block diagram of computer 50.

As shown in FIG. 2, the computer 50 includes an operation unit 51, which is an operation device such as a keyboard and a mouse, through which various operations are input, and a display device, such as an LCD (Liquid Crystal Display), which displays various information. a display unit 52, and a communication unit 53, which is a communication device that communicates with an external device via a network such as a LAN (Local Area Network) or the Internet, or directly by wire or wirelessly without going through a network. , a storage section 54 that is a non-volatile storage device such as a semiconductor memory or an HDD (Hard Disk Drive) for storing various information, and a control section 55 that controls the entire computer 50 .

The storage unit 54 stores a mass spectrometry program 54a for analyzing the mass of component gases of the sample gas. The mass spectrometry program 54a may be installed in the computer 50 at the time of manufacturing the computer 50, or may be stored in an external storage such as a CD (Compact Disk), a DVD (Digital Versatile Disk), or a USB (Universal Serial Bus) memory. It may be additionally installed on the computer 50 from a medium, or may be additionally installed on the computer 50 from a network.

The storage unit 54 stores a component gas candidate dictionary 54b as component gas candidate information indicating an ideal value of mass of a component gas candidate (hereinafter referred to as "component gas candidate") of the sample gas.

FIG. 3 is a diagram showing an example of the component gas candidate dictionary 54b.

As shown in FIG. 3, the component gas candidate dictionary 54b includes the ideal value of the mass (m/z) of the gas, the ID as identification information of the gas, and which energy generating section of the ionization section 20 is used to ionize the gas. Candidates for reference gas (hereinafter referred to as "reference gas") for correction of the measured value of the mass of the component gas detected in the measurement by mass spectrometry system 10 (hereinafter referred to as "reference gas") For each component gas candidate, reference gas candidate information indicating whether the gas is a candidate gas or not is shown for each component gas candidate. The ionizability information is generated based on the ionization energy of the component gas candidate and the energy generated by each energy generation section. Note that the component gas candidate dictionary 54b shown in FIG. 3 is drawn with information on some component gas candidates omitted, but in reality, there are many component gases other than the component gas candidates shown. Contains candidate information.

Here, reference gas candidates will be explained in detail.

FIG. 4A is a diagram showing the correspondence between the mass of each component gas of a specific sample gas measured by the mass spectrometry system 10 and the ionization energy. FIG. 4(b) is a mass spectrum obtained by corona discharge measurement for the sample gas shown in FIG. 4(a). FIG. 4(c) is a mass spectrum obtained by measuring 9.8 eV for the sample gas shown in FIG. 4(a).

FIG. 4A shows a line 61 of 9.8 eV, which is the energy generated by the UV lamp (9.8 eV) 23b, in order to explain the method for selecting a reference gas candidate.

As shown in FIG. 4, gases with ionization energy of 9.8 eV or less are observed in both corona discharge measurement and 9.8 eV measurement. On the other hand, gases with ionization energy greater than 9.8 eV are observed only in the corona discharge measurement and in the 9.8 eV measurement. Therefore, the reference gas candidates are selected from gases whose ionization energy is greater than 9.8 eV, which is the energy generated by the UV lamp (9.8 eV) 23b, and less than or equal to the energy generated by the corona discharge section 23a. Note that among all types of VOC (Volatile Organic Compounds) gases, the proportion of gases with ionization energy of 9.8 eV or less is approximately 50%. Among all types of VOC gas, the proportion of gas types whose ionization energy is equal to or lower than that generated by the corona discharge section 23a is approximately 100%.

Since at least two reference gases are required for mass correction, a plurality of reference gas candidates need to be selected.

The reference gas candidate includes "another gas whose ionization energy is greater than 9.8 eV and less than or equal to the energy generated by the corona discharge section 23a" within a specific mass range that includes the mass of the reference gas candidate itself. It is preferable not to do so from the viewpoint of reducing the possibility of incorrect determination of the reference gas. In this embodiment, such a reference gas candidate is selected. Here, the specific mass range refers to the maximum value of the expected error expressed in mass (hereinafter referred to as "assumed error When a is the maximum mass value (referred to as "maximum mass value"), for example, the range is greater than "ma" and smaller than "m+a". For example, the maximum expected error mass value a is the maximum mass detectable by the mass spectrometry system 10 of 300 m/z, and the maximum expected error expressed as a percentage with respect to the mass detected by the mass spectrometry system 10. If the value is 2%, then 6 m/z is 2% of 300 m/z.

For example, among the gases shown in FIG. 4, gases 62, 63, 64, and 65 are selected as reference gas candidates. _Here , _the gases 62 and 65 are _N2 and _C2Cl3F3 , respectively. Note that various gases such as O ₂ can be employed as the gas selected as the reference gas candidate.

Note that the reference gas candidate is set, for example, by the manufacturer of the mass spectrometry system 10. The reference gas candidate may be set by a user of the mass spectrometry system 10, for example.

The control unit 55 shown in FIG. 2 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores programs and various data, and a memory used as a work area for the CPU of the control unit 55. RAM (Random Access Memory). The CPU of the control unit 55 executes a program stored in the storage unit 54 or the ROM of the control unit 55.

The control unit 55 executes the mass spectrometry program 54a to control the measurement control unit 55a, which controls the measurement by the mass spectrometry system 10, and the plurality of component gases detected by the measurement by the mass spectrometry system 10, which have different masses. A reference gas determination unit 55b that determines a plurality of reference gases, and a correction of the measured value of the mass of the component gas based on the relationship between the ideal value and the measured value of the mass of the plurality of reference gases determined by the reference gas determination unit 55b. A measured value correction section 55c for execution and a component type identification section 55d for identifying the type of component gas detected by the measurement by the mass spectrometry system 10 are realized.

Next, the operation of the mass spectrometry system 10 when performing measurement will be explained.

FIG. 5 is a timing chart of the operation of the mass spectrometry system 10 when performing measurements.

When the measurement control unit 55a is instructed to start measurement via the operation unit 51, the measurement control unit 55a executes the operation shown in FIG.

As shown in FIG. 5, the measurement control unit 55a turns on the suction pump 22 at time t1. Therefore, the sample gas is introduced into the ionization chamber 21 from the sample gas inlet 21a under atmospheric pressure by being sucked by the suction pump 22.

After turning on the suction pump 22, the measurement control section 55a turns on the corona discharge section 23a via the switching control section 24. Therefore, the component gases of the sample gas introduced into the ionization chamber 21 are ionized by the corona discharge section 23a.

After turning on the corona discharge section 23a, the measurement control section 55a starts control to linearly increase the voltage of the extraction electrode 33 from -10 kV to 0 V via the scanning voltage control section 35 at time t2. Therefore, the ions generated by the corona discharge section 23a are extracted from the ionization chamber 21 into the vacuum chamber 31 through the ion discharge port 21c of the ionization chamber 21 by the extraction electrode 33 and accelerated. The ions accelerated by the extraction electrode 33 have their trajectories bent by the magnetic field generated by the magnet 36, and only those that follow a specific trajectory enter the Faraday cup 41 and are detected by the Faraday cup 41. The current detected by the Faraday cup 41 is input as a voltage to the computer 50 via a current-voltage conversion amplifier (not shown).

Note that by changing the voltage of the extraction electrode 33, the acceleration of the ions by the extraction electrode 33 changes, and the speed of the ions after passing through the extraction electrode 33 changes. The ion traveling along the trajectory entering the Faraday cup 41 is determined by the speed after passing through the extraction electrode 33 and the mass of the ion itself. Therefore, the ions detected by the Faraday cup 41 have a mass that corresponds to the voltage of the extraction electrode 33.

Therefore, the measurement control unit 55a can acquire, for each mass corresponding to the voltage of the extraction electrode 33, a mass spectrum indicating the intensity of ion detection according to the voltage (hereinafter referred to as "ion detection intensity"). Note that the computer 50 stores the acquired mass spectrum.

When the measurement control unit 55a finishes the measurement when the component gas of the sample gas is ionized by the corona discharge unit 23a, the measurement control unit 55a starts the measurement when the component gas of the sample gas is ionized by the UV lamp (9.8 eV) 23b. Execute in the same way.

Note that in the above, the measurement control unit 55a executes the 9.8 eV measurement after the corona discharge measurement. However, the measurement control unit 55a may perform the corona discharge measurement and the 9.8 eV measurement in any order.

FIG. 6 is a diagram showing an example of measurement results obtained by the operation shown in FIG. 5.

The measurement control unit 55a stores, for example, the measurement results shown in FIG. 6 in the storage unit 54 as the measurement results obtained by the operation shown in FIG. The measurement results shown in Figure 6 include the detected component gas for each mass measurement value, that is, for each gas, the mass measurement value, the ion detection intensity, the corona discharge measurement, and the 9.8 eV measurement. It also includes detection status information indicating whether the detection has occurred. The ion detection intensities include those in corona discharge measurement and those in 9.8 eV measurement. Note that the measurement results shown in Figure 6 are drawn with the specific values of the measured mass and ion detection intensity omitted, but in reality, they do not include the specific values. I'm here. Furthermore, although the measurement results shown in FIG. 6 are drawn with information on some gases omitted, they actually include information on many gases in addition to the gases shown.

Next, the operation of the mass spectrometry system 10 when identifying the type of component gas of the sample gas will be described.

FIG. 7 is a flowchart of the operation of the mass spectrometry system 10 when identifying the type of component gas of the sample gas.

When the measurement operation shown in FIG. 5 is completed, the reference gas determination unit 55b executes the operation shown in FIG. 7.

As shown in FIG. 7, the reference gas determination unit 55b executes a reference gas determination process to determine a reference gas (S101).

FIG. 8 is a flowchart of a part of the reference gas determination process shown in FIG. FIG. 9 is a flowchart that is a continuation of the flowchart shown in FIG.

As shown in FIGS. 8 and 9, the reference gas determination unit 55b creates a column in which gases indicated as reference gas candidates in the component gas candidate dictionary 54b are arranged in ascending order with respect to mass (hereinafter referred to as "reference gas candidate column"). Target the first gas (S121).

Next, the reference gas determining unit 55b assigns the mass associated with the current target gas in the component gas candidate dictionary 54b to the variable m (S122).

Next, the reference gas determination unit 55b determines whether a component gas whose measured mass value is greater than "ma" and smaller than "m+a" is detected in the corona discharge measurement (S123). Here, a is the assumed maximum error mass value mentioned above.

When the reference gas determination unit 55b determines in S123 that a component gas whose mass measurement value is greater than "m-a" and smaller than "m+a" is detected in the corona discharge measurement, the reference gas determination unit 55b determines the mass measurement value detected in the corona discharge measurement. It is determined whether there is a component gas that was not detected in the 9.8 eV measurement among the component gases in which the value is greater than "ma" and smaller than "m+a" (S124).

The reference gas determining unit 55b determines in S123 that a component gas whose mass measurement value is greater than "m-a" and smaller than "m+a" is not detected in the corona discharge measurement, or If it is determined in S124 that there is no component gas that was not detected in the 9.8 eV measurement among the component gases whose measured values are greater than "m-a" and smaller than "m+a", the current The gas immediately after the target gas is set as a new target (S125), and the process of S122 is executed.

The reference gas determination unit 55b determines that among the component gases detected in the corona discharge measurement and whose measured mass values are greater than "m-a" and smaller than "m+a", there is a component gas that was not detected in the 9.8 eV measurement. Then, as determined in S124, among the component gases detected in the corona discharge measurement whose measured mass value is greater than "m-a" and smaller than "m+a", the mass of the component gas not detected in the 9.8 eV measurement is determined. The measured value is determined as the measured value of the mass of the first reference gas (S126). The current value of the variable m is determined as the ideal value of the mass of the first reference gas (S127). Note that, as described above, the reference gas candidates in the component gas candidate dictionary 54b are defined as those whose ionization energy is greater than 9.8 eV and whose ionization energy is greater than 9.8 eV within a specific mass range that includes the mass of the reference gas candidate itself. It is selected that there is no other gas whose energy is less than the energy generated. Therefore, among the component gases whose measured mass value is greater than "m-a" and smaller than "m+a" detected in the corona discharge measurement, the component gas determined in S124 as not being detected in the 9.8 eV measurement is the component gas. Only one exists in the gas candidate dictionary 54b.

Next, the reference gas determining unit 55b targets the last gas in the reference gas candidate string (S128).

Next, the reference gas determining unit 55b assigns the mass associated with the current target gas in the component gas candidate dictionary 54b to the variable m (S129).

Next, the reference gas determining unit 55b determines whether a component gas whose measured mass value is greater than "ma" and smaller than "m+a" is detected in the corona discharge measurement (S130). Here, a is the assumed maximum error mass value mentioned above.

When the reference gas determining unit 55b determines in S130 that a component gas whose measured mass value is greater than "m-a" and smaller than "m+a" is detected in the corona discharge measurement, the reference gas determination unit 55b determines the measured mass value detected in the corona discharge measurement. It is determined whether there is a component gas that was not detected in the 9.8 eV measurement among the component gases in which the value is greater than "m−a" and smaller than "m+a" (S131).

The reference gas determination unit 55b determines in S130 that a component gas whose mass measurement value is greater than "m-a" and smaller than "m+a" is not detected in the corona discharge measurement, or If it is determined in S131 that there is no component gas that was not detected in the 9.8 eV measurement among the component gases whose measured values are greater than "m-a" and less than "m+a", the current The gas immediately before the target gas is set as a new target (S132), and the process of S129 is executed.

The reference gas determination unit 55b determines that among the component gases detected in the corona discharge measurement and whose measured mass values are greater than "m-a" and smaller than "m+a", there is a component gas that was not detected in the 9.8 eV measurement. Then, it is determined in S131 that among the component gases detected in the corona discharge measurement whose measured mass value is greater than "m-a" and smaller than "m+a", the mass of the component gas not detected in the 9.8 eV measurement is The measured value is determined as the measured value of the mass of the second reference gas (S133). The current value of the variable m is determined as the ideal value of the mass of the second reference gas (S134). Note that, as described above, the reference gas candidates in the component gas candidate dictionary 54b are defined as those whose ionization energy is greater than 9.8 eV and whose ionization energy is greater than 9.8 eV within a specific mass range that includes the mass of the reference gas candidate itself. It is selected that there is no other gas whose energy is less than the energy generated. Therefore, among the component gases whose measured mass values are greater than "m-a" and smaller than "m+a" detected in the corona discharge measurement, the component gases determined in S131 as not being detected in the 9.8 eV measurement are Only one exists in the gas candidate dictionary 54b.

After the process of S134, the reference gas determination unit 55b ends the reference gas determination process shown in FIGS. 8 and 9.

As shown in FIG. 7, upon completion of the reference gas determination process in S101, the measured value correction unit 55c executes a mass correction process to correct the mass measured in the corona discharge measurement (S102). Specifically, the measured value correction unit 55c corrects each mass measured in the corona discharge measurement using the following equation (1). In the equation shown in Equation 1, t1 is the measured value of the mass of the first reference gas determined in S126. t2 is the measured value of the mass of the second reference gas determined in S133. tx is the mass measured in the corona discharge measurement. T1 is the ideal value of the mass of the first reference gas determined in S127. T2 is the ideal value of the mass of the second reference gas determined in S134. Tx is the mass after performing the correction.

FIG. 10(a) is an explanatory diagram of the mass correction process when the measured mass of the first reference gas is smaller than the ideal value and the measured mass of the second reference gas is larger than the ideal value. . FIG. 10(b) is an explanatory diagram of the mass correction process when the measured value of the mass of the first reference gas is larger than the ideal value and the measured value of the mass of the second reference gas is also larger than the ideal value. . FIG. 10(c) is an explanatory diagram of the mass correction process when the measured mass of the first reference gas is smaller than the ideal value and the measured mass of the second reference gas is also smaller than the ideal value. . FIG. 10(d) is an explanatory diagram of the mass correction process when the measured mass of the first reference gas is larger than the ideal value and the measured mass of the second reference gas is smaller than the ideal value. .

In any case shown in FIG. 10, the mass measured in the corona discharge measurement is corrected to an appropriate value by the mass correction process in S102.

FIG. 11 is a diagram illustrating an example of measurement results to which measurement values after correction are added.

The measured value correction unit 55c changes the measurement result shown in FIG. 6 to the measurement result shown in FIG. 11 through the mass correction process in S102. The measurement results shown in FIG. 11 are obtained by adding "measured values after correction" generated by the mass correction process in S102 to the measurement results shown in FIG. 6. Note that the measurement results shown in FIG. 11 are drawn with the specific values of the measured mass before correction and the specific values of the ion detection intensity omitted, but in reality, Contains a value. Further, although the measurement results shown in FIG. 11 are drawn with information on some gases omitted, they actually include information on many gases other than the gases shown.

As shown in FIG. 7, when the mass correction process in S102 is completed, the component type identifying unit 55d executes a component type identifying process to identify the type of the measured component gas (S103).

FIG. 12 is a flowchart of the component type identification process shown in FIG. 7.

As shown in FIG. 12, the component type identifying unit 55d targets one component gas that has not been targeted in the current component type identifying process, among the component gases detected in the corona discharge measurement (S141).

Next, the component type specifying unit 55d stores a plurality of component gas candidates in the component gas candidate dictionary that are associated with the same ideal value as the measured value after execution of the correction in the mass correction process of S102 for the current target component gas. 54b (S142).

The component type identifying unit 55d stores a plurality of component gas candidates in the component gas candidate dictionary 54b that are associated with the same ideal value as the measured value after the correction in the mass correction process of S102 for the current target component gas. If it is determined in S142 that it does not exist, the ID of the component gas candidate that is associated with the same ideal value as the measured value after execution of the correction in the mass correction process of S102 for the current target component gas is stored in the current target component gas. It is determined as the ID of the component gas (S143).

The component type identifying unit 55d stores a plurality of component gas candidates in the component gas candidate dictionary 54b that are associated with the same ideal value as the measured value after the correction in the mass correction process of S102 for the current target component gas. If it is determined in S142 that the component gas exists, the ID of the component gas candidate whose ionizable information in the component gas candidate dictionary 54b matches the detection status information of the measurement result is selected from among the plurality of component gas candidates as the component gas of the current target component gas. It is determined as an ID (S144). Note that the corona discharge section and UN lamp (9.8 eV) in the ionizable information correspond to corona discharge measurement and 9.8 eV measurement in the detection status information, respectively. For example, if the corona discharge part and UN lamp (9.8eV) in the ionizable information are ○ and ×, respectively, and the corona discharge measurement and 9.8eV measurement in the detection status information are ○ and ×, respectively, the component The type identifying unit 55d determines that the ionizable information matches the detection status information. In addition, even if the corona discharge part and UN lamp (9.8eV) in the ionizable information are both ○, and the corona discharge measurement and 9.8eV measurement in the detection status information are both ○, the component type can be identified. The unit 55d determines that the ionizable information matches the detection status information.

After the process of S143 or S144, the component type identification unit 55d determines whether there is any component gas that has not been targeted in the current component type identification process among the component gases detected in the corona discharge measurement. (S145).

If the component type specifying unit 55d determines in S145 that there is a component gas that has not yet been targeted in the current component type specifying process, it executes the process in S141.

If the component type specifying unit 55d determines in S145 that there is no component gas that has not been targeted in the current component type specifying process, it ends the component type specifying process shown in FIG. 12.

FIG. 13 is a diagram showing an example of a measurement result with an ID added.

The component type specifying unit 55d changes the measurement result shown in FIG. 11 to the measurement result shown in FIG. 13 by the component type specifying process shown in FIG. 12. The measurement results shown in FIG. 13 are obtained by adding the gas ID to the measurement results shown in FIG. 11. Note that the measurement results shown in FIG. 13 are drawn with the specific values of the measured mass before correction and the specific values of the ion detection intensity omitted, but in reality, the specific values of the measured mass and the ion detection intensity are omitted. Contains a value. Furthermore, although the measurement results shown in FIG. 13 are drawn with information on some gases omitted, they actually include information on many gases other than the gases shown.

As shown in FIG. 7, upon completion of the component type identification process in S103, the component type identification unit 55d ends the operation shown in FIG.

As explained above, the mass spectrometry system 10 uses the component gas itself of the sample gas as the reference gas for correcting the measured value of the mass of the component gas detected in the measurement (S121 to S134). There is no need to use a different gas for correction, and convenience can be improved.

The more types of component gases there are in the sample gas, the higher the possibility that the reference gas will be determined by the mass spectrometry system 10. Examples of gases with many kinds of component gases include exhaled breath containing dozens or more component gases, and gases having odors.

Gases of the same type are likely to contain many component gases of the same type. For example, gases that have a specific type of odor, such as gases that have a coffee scent or gases that have a bad odor from a poultry farm, are likely to contain many component gases of the same type. When the mass spectrometry system 10 detects a similar component gas each time a measurement is performed, the possibility that a reference gas candidate will be appropriately selected can be improved, so the reference gas is determined from the component gas itself of the sample gas. The possibility of being able to do something can be improved. Therefore, mass spectrometry system 10 is preferably provided as a dedicated system for a particular type of gas. For example, the mass spectrometry system 10 may be provided as a system dedicated to gas having a specific type of odor, such as a system dedicated to gas having a coffee aroma or a system dedicated to gas having a foul odor from a poultry farm. good.

When the component gas candidate dictionary 54b includes a plurality of component gas candidates that are associated with the same ideal value as the measured value after correction (YES in S142), the mass spectrometry system 10 selects a plurality of component gas candidates. Based on the ionization energy of each candidate and the detection status information, it is determined which of the plurality of component gas candidates the component gas corresponds to (S144), so the accuracy of identifying the component gas can be improved. .

The mass spectrometry system 10 is capable of high-speed measurement similar to conventional mass spectrometry systems. Furthermore, the mass spectrometry system 10 can detect the component gases of the sample gas with high precision compared to conventional mass spectrometry systems. Therefore, the mass spectrometry system 10 can perform baggage inspections at airports, for example, in place of detection dogs that detect illegal drugs and explosives.

The mass spectrometry system 10 selects the component gas that has the smallest measured mass value among the component gases that satisfy the condition that "the measured mass value is greater than "m-a" and smaller than "m+a" and is not detected in corona discharge measurement." The component gases and the largest component gas are determined as reference gases (S121 to S134). Therefore, the mass spectrometry system 10 can improve the effect of reducing errors due to correction in the mass correction process of S102. However, the mass spectrometry system 10 detects that the measured mass value of the component gases that satisfy the condition that "the measured mass value is greater than 'm-a' and smaller than 'm+a' and is not detected in corona discharge measurement". At least one of the minimum component gas and the maximum component gas is replaced by another gas that satisfies the condition that "the measured value of the mass is larger than "m-a" and smaller than "m+a" and is not detected in corona discharge measurement." It may be replaced with a component gas.

Note that the mass spectrometry system 10 uses two types of energy generating sections, the corona discharge section 23a and the UV lamp (9.8 eV) 23b, which generate different energies. However, the mass spectrometry system 10 may use three or more types of energy generating units that generate different energies.

FIG. 14 is a configuration diagram of a mass spectrometry system 10 including three types of energy generating sections.

As shown in FIG. 14, the ionization section 20 includes a UV lamp (hereinafter referred to as "UV lamp (10.6 eV)") 23c as an energy generating section that generates energy of 10.6 eV. A UV lamp (10.6 eV) 23c is placed inside the ionization chamber 21. Note that among all types of VOC gases, the proportion of gases with ionization energy of 10.6 eV or less is approximately 80%.

In the mass spectrometry system 10 shown in FIG. 1, "a gas whose ionization energy is greater than 9.8 eV and less than or equal to the energy generated by the corona discharge section 23a" is employed as a reference gas candidate. In the mass spectrometry system 10 shown in FIG. 14, "a gas whose ionization energy is greater than 9.8 eV and less than or equal to 10.6 eV" and "a gas whose ionization energy is greater than 10.6 eV and which is generated by the corona discharge section 23a" are used. Any gas that has an energy equal to or less than that of the gas can be adopted as a reference gas candidate. The mass spectrometry system 10 shown in FIG. 14 has a narrower energy range for identifying the reference gas than the mass spectrometry system 10 shown in FIG. 1, which reduces the possibility of erroneously identifying the reference gas. Can be done. Furthermore, compared to the mass spectrometry system 10 shown in FIG. 1, the mass spectrometry system 10 shown in FIG. 14 can increase the types of energy ranges that can be associated with component gas candidates in the component gas candidate dictionary 54b. When a plurality of ideal values that are the same as the measured value after correction are present in the component gas candidate dictionary 54b, it is possible to reduce the possibility of erroneously specifying the type of component gas.

10 Mass spectrometry system 54b Component gas candidate dictionary (component gas candidate information)
55a Measurement control section 55b Reference gas determination section 55c Measured value correction section 55d Component type identification section 62, 63, 64, 65 Gas (reference gas candidate)

Claims (2)

A mass spectrometry system that ionizes and analyzes the mass of a component gas that is a component gas of a sample gas,
a measurement control unit that controls measurement of the sample gas by the mass spectrometry system;
a reference gas determination unit that determines a reference gas that is a reference gas for correction of the measured value of the mass of the component gas detected in the measurement of the sample gas;
and a measured value correction unit that performs the correction,
The measurement control unit executes a plurality of measurements in which the component gas is ionized with mutually different energies,
The reference gas determining unit is configured to determine whether the measured value is within a specific mass range that includes an ideal mass of a reference gas candidate that is a candidate for the reference gas, and in which of the plurality of measurements the component gas is Based on the detection status information indicating whether the component gas is detected, the measurement in which the component gas is detected among the plurality of measurements is the component gas that matches the measurement in which the reference gas candidate is ionized among the plurality of measurements. Determined as the reference gas,
The reference gas determination unit determines a plurality of reference gases having different masses from among the plurality of component gases detected in the measurement of the sample gas ,
The mass spectrometry system is characterized in that the measured value correction unit executes the correction based on the relationship between the ideal value of mass of the plurality of reference gases determined by the reference gas determination unit and the measured value. comprising a component type identification unit that identifies the type of the component gas,
The component type identifying unit is configured to select the component gas candidate information that is the same as the measured value after the correction is performed by the measured value correcting unit, in the component gas candidate information indicating the ideal value of the mass of the component gas candidate that is the component gas candidate. When a plurality of component gas candidates are associated with an ideal value, the component gas is determined to be one of the plurality of component gases based on the ionization energy of each of the plurality of component gas candidates and the detection status information. The mass spectrometry system according to claim 1, wherein the mass spectrometry system specifies which of the gas candidates it corresponds to.

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