JP4305064B2 - Explosive detection method and apparatus - Google Patents

Description

これに対して、低揮発性グループの測定時間を式３から式４の範囲として規定する。
【００２２】

これによって高揮発性、低揮発性各グループを時間軸上で分離することができる。なお、この結果により、テーブル２１０、２１１の各々に予め登録すべき爆発物がある程度推定可能となる。
【００２３】
【発明の効果】
以上述べたように、本発明によれば、短時間で爆発物等の物質を分析し特定する方法およびそれを用いた質量分析装置を提供することができる。
【００２４】
また、本発明によれば、物質採集用紙に採集された微量な爆発物を、高感度に検出することが可能となる。特に揮発性の高い爆発物について高精度に判別することが可能となる。
【図面の簡単な説明】
【図１】爆発物探知装置の構成を示す図である。
【図２】測定部２０の構成を示す図である。
【図３】高揮発性の爆発物に関する情報を記憶するテーブル２１０の構成を示す図である。
【図４】低揮発性の爆発物に関する情報を記憶するテーブル２１１の構成を示す図である。
【図５】高揮発性又は低揮発性の爆発物成分のイオン質量とその強度の関係を示す図である。
【図６】測定部２０における爆発物探知の処理を示すフローチャートである。
【図７】高揮発性グループ、低揮発性グループの測定時間軸とイオン信号強度の関係を示す図である。
【符号の説明】
１…物質採集用紙導入機構、２…物質採集用紙加熱炉、３…物質採集用紙挿入検知回路、４…成分ガス流路、５…イオン源、６…コロナ放電電極、７…差動排気部、８…静電レンズ、９…ポンプ、１０…差動真空ポンプ、１１…真空ポンプ、１２…バックポンプ、１３…真空チャンバ、１４…四重極分析管、１５…二次電子増倍管、１６…信号増幅器、１７…静電レンズ電圧制御部、１８…四重極分析管制御部、１９…Ａ／Ｄコンバータ、２０…測定部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mass spectrometer, and more particularly to a method and apparatus for detecting a substance such as an explosive.
[0002]
[Prior art]
An example of a mass spectrometer is described in Japanese Patent Application Laid-Open No. 2000-195464 (Patent Document 1). Japanese Patent Application Laid-Open No. 2000-195464 discloses a method of returning a high-frequency voltage value from a final voltage to an initial voltage after performing a selected ion monitoring measurement (SIM measurement) while controlling the voltage stepwise. Measurement time, that is, settling time, is used to investigate the presence or absence of contaminants in the sample using the data obtained by this scan measurement, and to collect information for identifying the contaminants. A possible quadrupole mass spectrometer is described.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-195464
[Problems to be solved by the invention]
Japanese Patent Laid-Open No. 2000-195464 merely collects the presence / absence of impurities contained in the sample and information for identifying the impurities, and does not describe a method for specifically identifying the impurities. Therefore, in order to specify the impurities, additional measurement is required separately, and it takes time to specify the impurities. On the other hand, explosives and other substances are related to human life and need to be identified in a short time.
[0005]
Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for analyzing and specifying a substance such as an explosive in a short time and a mass spectrometer using the same.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention assigns priorities to components constituting explosives and performs measurement from components or molecular ions having higher priorities. Further, when ions having a mass number considered to be explosives are measured from an object to be determined, only ions associated with the explosive list are to be measured. The explosives to be classified are also divided into those that are likely to evaporate and must be measured in a shorter time, and those that do not.
[0007]
The ion that is always observed when a certain type of explosive is measured is adopted as the first measurement, and this is used as the first ion. When the first ion is observed, the ion configuration in the registration information of the explosive component is referred to, and the second ion expected for the explosive candidate containing the first ion is selected and measured. Here, another component expected from the first ion, that is, the third ion may be measured. Moreover, you may measure the 3rd ion linked | related similarly to the time of 1st ion detection at the time of measuring 2nd ion. By measuring only the relevant ions of explosives that are expected from the ion mass numbers measured in this way, the molecular ion mass number that must be measured is reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of the explosive detection device of the present invention.
[0009]
1 is an introduction mechanism for putting a material collection paper (sample) with explosives attached thereto into a heating furnace, 2 is a heating furnace for heating the material collection paper attached to the introduction mechanism, and 3 is a material collection paper. A detection circuit for detecting insertion of the installed introduction mechanism into the heating furnace, 4 is a component gas suction part, and a flow path for introducing the sample gas into the ion source, 5 is for ionizing the gasified sample An ion source, 6 is a corona discharge electrode for ionizing a sample gas by corona discharge, 13 is a vacuum chamber containing a quadrupole mass spectrometer tube, and 7 is for inducing ionized gas components to the vacuum chamber by electromagnetic induction. A differential exhaust unit, 8 is an electrostatic lens for efficiently concentrating ions to the quadrupole analyzer tube, and 9 is for introducing sample gas into the flow path and discharging unnecessary molecules and gas components that are not ionized. Po , 11 is a vacuum pump for making the vacuum chamber a high vacuum, 10 is a differential vacuum pump for making the inside of the differential evacuation unit 7 an intermediate vacuum between the vacuum of the vacuum chamber 13 and the atmospheric pressure, and 12 is a vacuum pump 11. And a back pump for discharging the exhaust of the differential vacuum pump 10 to atmospheric pressure, 15 a secondary electron multiplier for converting the intensity of the received molecular ions into a current value, 16 a signal amplifier, and 14 an introduction A quadrupole analyzer tube that filters the molecular ions that have been subjected to voltage and alternating current components and introduces only molecular ions of a target mass number into the secondary electron multiplier tube 15, 17 is a voltage control unit of the electrostatic lens 8, and 18 A quadrupole analyzer control unit that controls measurement conditions (ion permeation conditions), 19 is an A / D converter that converts a received signal into a digitized value (mass measurement data), and 20 is for the quadrupole analyzer control unit 18. It is a measurement unit that controls the setting of measurement conditions and acquires mass measurement data from the A / D converter 19 to perform explosives determination and component determination.
[0010]
When the material collection paper with the sample attached is attached to the introduction unit 1 and inserted into the heating furnace 2, the sample component is heated by the heating furnace and the attached sample component is gasified and passes through the flow path 4 to be an ion source. Reach 5 The gas component that has reached the ion source 5 is ionized by the corona discharge electrode 6, passes through the differential exhaust section 7 by electromagnetic induction, is converged by the electrostatic lens 8, and reaches the quadrupole analysis tube 14. At this time, the frequency component and voltage applied to the quadrupole analyzer tube 14 are set by the quadrupole analyzer controller 18 so that only ions having a target mass number are selected and received by the secondary electron multiplier 15. The signal amplifier 16 amplifies the signal to a signal strength that the A / D converter 19 can receive. The ion intensity is measured by the measurement unit 20 observing the current signal converted into the digitized value by the A / D converter.
[0011]
When the sample is inserted into the preheated heating furnace 2, since the introduction mechanism 1 is physically moved, the sample is heated before the detection is detected by the detection circuit 3, and the components are gasified. In addition, when a highly volatile explosive component is introduced into the heating furnace 2, before changing the measurement conditions such as the frequency and voltage of the quadrupole mass spectrometer tube 14 to the desired permeation conditions, the mass number to be measured is adjusted. All components are introduced into the quadrupole mass spectrometer tube 14 when other measurement conditions (other mass numbers) are being measured. In this case, as the operational characteristics of the quadrupole mass spectrometer, all ions with masses other than the transmission conditions are discarded without being measured, so that even if explosives are present, the components cannot be detected. . In the present invention, mass number measurement is effectively performed by referring to the explosive registration information in conjunction with the detection circuit 3 and setting the minimum and optimum measurement order.
[0012]
FIG. 2 is a diagram illustrating a configuration of the measurement unit 20. The measurement unit 20 includes a processor 200, a memory 201 that stores an explosive detection program executed by a processor, and a memory 202 that stores explosive registration information. In the explosive registration information storage memory 202, a table 210 (FIG. 3) for storing information on high volatility explosives as main components and subcomponents, and information on low volatility explosives as main components, Stored is a table 211 (FIG. 4) that is classified and stored as subcomponents.
[0013]
FIG. 3 is a diagram showing a configuration of a table 210 that stores information on highly volatile explosives. In the table 210, information on a plurality of highly volatile explosives is stored in advance. The information is obtained from each information of the explosive name 210-1, the main component 210-2, the ion mass 210-3 of the main component, the subcomponent 210-4, and the ion mass 210-5 of the subcomponent. Become.
[0014]
FIG. 4 is a diagram illustrating a configuration of a table 211 that stores information on low-volatile explosives. Information relating to a plurality of low-volatile explosives is stored in the table 211 in advance. The information includes the explosive name 211-1, the main component 210-2, the ion mass 210-3 of the main component, the subcomponent 210-4, and the ion mass 210-5 of the subcomponent. Become.
[0015]
FIG. 5 is a diagram showing the relationship between the ion mass of a highly volatile or low volatile explosive component and its strength. The upper diagram shows the relationship between the ion mass of the main component and its strength, and the lower diagram shows the relationship between the ion mass of the subcomponent accompanying the main component ion and its strength. For example, subcomponents 610-1 and 610-2 indicate that they are associated with the main component 510-1 of the explosive. Here, 500-1, 500-2,..., 500-n are threshold values predetermined for the main component ions to be measured, and 600-1, 600-2,. The predetermined threshold value for the secondary component ions is shown.
[0016]
Although details will be described later, the measurement unit 20 gives the transmission condition for measuring the main ions to the quadrupole analysis tube control unit 18. The quadrupole analysis tube control unit 18 controls the frequency voltage applied to the quadrupole analysis tube 14, and when a main ion 25 exceeding a threshold value for measuring the mass of the target ion (main component) is observed, With reference to the tables 210 and 211, transmission conditions for measuring ions registered as subcomponents are given from the measurement unit 20 to the quadrupole analyzer control unit 18, and the mass of the subcomponents is measured. When all of the main component ions and subcomponent ions exceed the threshold value, that is, when all the explosive components registered in the tables 210 and 211 are detected, the measurement object is determined as an explosive and the type is determined. This is displayed on the display of the measurement unit 20.
[0017]
In addition, in order to effectively detect explosive components classified in the high volatility group, the detection of the high volatility group is repeated until the introduction of the measurement target component is confirmed by receiving the signal from the detection circuit 3, and detection is performed. When the detection signal of the circuit 3 is received, the predetermined number of measurement data is retroactively added to the determination target data. This takes into account the time lag from when the substance collection sheet is introduced into the introduction section 1 until the detection circuit 3 detects it, and the time during which the component gas passes through the flow path. When the signal of the detection circuit 3 is received and the measurement of the high volatile group is completed, the measurement of the low volatile group is performed.
[0018]
FIG. 6 is a flowchart showing the explosive detection process in the measurement unit 20. The measurement processor 200 waits for a signal from the detection circuit 3 and measures the main ion signal of the highly volatile explosive (step 60). The processor 200 determines the peak detection of the main ion of the highly volatile explosive (step 61), and if a peak is detected, the processor 200 detects the secondary ion associated with the main ion peak of the highly volatile explosive. Measurement is performed (step 62). Next, the processor 200 determines whether or not the signal from the detection circuit 3 is detected (step 63). If no signal is detected, the processor 200 returns to step 60.
If the insertion of the material collection sheet is confirmed by receiving the detection signal from the detection circuit 3 in step 63, the main ion and sub ion signals of the high volatility group of the specified measurement number accumulated so far are obtained. Referring to this, it is determined whether or not all the registered peaks have been detected, that is, whether or not the explosive is present and the explosive type is determined (step 64). Next, after checking the measurement times repeatedly at Step 65, the processor 200 measures the low volatility group if the prescribed measurement times have not been reached (Step 66). Next, the processor 200 counts the measurement times counter (step 67) and determines the presence or absence of the main ion peak of the low volatility group (step 78). If it is determined that there is a peak, the side ions associated with the main ions of the low-volatility explosive are measured (step 69). Next, the processor 200 determines whether or not there is a secondary ion peak (step 70). If it is determined that there is a peak of sub-ions, the determination of explosives and the type of explosives are performed (step 71). If there is no primary ion or no associated secondary ion, the highly volatile group is measured. After checking the repeated measurement times (step 72), if the specified measurement times have not been reached, the highly volatile explosives are measured (step 73). The processor 200 counts the measurement times counter (step 74) and determines the presence or absence of the main ion peak of the highly volatile explosive (step 75). If it is determined that there is a peak, the side ions associated with the main ions of the highly volatile explosives are measured (step 76). The processor 200 determines whether or not there is a secondary ion peak (step 77). If it is determined that there is a secondary ion peak, the processor 200 determines whether or not the explosive material is present and determines the explosive material type (step 78). The processor 200 outputs the explosive species after performing the repeated measurement of the specified number of times (step 79). When it is detected that the substance collection sheet has been removed from the introduction unit 1, the process returns to step 60. The threshold value for determining the peak is set from the signal intensity of the background noise component of the ions acquired in advance without attaching anything to the substance collection sheet.
[0019]
According to this embodiment, when the main component does not exceed the threshold, it is not necessary to acquire the subcomponent. Therefore, by repeating the measurement until the time when it is expected to completely volatilize to the low volatility explosive component, the explosive detection device optimizes the explosive component registered in the discrimination table and eliminates unnecessary ion measurement. As a result, it is possible to speed up the measurement. Further, since the gas heated in the heating furnace is concentrated at a high concentration in a short time and reaches the quadrupole mass spectrometer tube 14, the gas component of the explosive in a high concentration state can be measured by this acquisition method. it can. In addition, when it is a volatile explosive substance and its ionic strength is quite high, it may adhere to the flow path 4 etc. and may affect the next measurement. Therefore, in this case, the process may be terminated in step 64.
[0020]
FIG. 7 is a diagram illustrating the relationship between the measurement time axis and the ion signal intensity of the high volatile group and the low volatile group. In the figure, reference numeral 700 denotes an ion signal of a highly volatile explosive, and reference numeral 701 denotes an ion signal of a low volatile explosive. The horizontal axis is the time axis from the start of measurement, and the vertical axis is the normalized ion signal intensity. The measurement start point is the starting point of the ion intensity signal, the time until the maximum peak detection of the high volatile component group is t _p1 , and the time until the maximum peak detection of the low volatile component group is t _p2 . In addition, the strength maintenance time of the high volatile group at the strength where the ionic strength of the high volatile group and the ionic strength of the low volatile group at the normalized strength is t _w1 , and the strength maintenance time of the low volatile group is t _w2 To do. At this time, the measurement time of the highly volatile group is defined as the range of Formula 1 to Formula 2.
[0021]

On the other hand, the measurement time of the low volatility group is defined as the range of Equation 3 to Equation 4.
[0022]

As a result, the high and low volatile groups can be separated on the time axis. This result makes it possible to estimate to some extent the explosives to be registered in advance in each of the tables 210 and 211.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method for analyzing and specifying substances such as explosives in a short time and a mass spectrometer using the method.
[0024]
Further, according to the present invention, it is possible to detect a very small amount of explosives collected on a substance collection sheet with high sensitivity. In particular, highly volatile explosives can be identified with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an explosive detection device.
FIG. 2 is a diagram illustrating a configuration of a measurement unit 20;
FIG. 3 is a diagram showing the configuration of a table 210 that stores information on highly volatile explosives.
FIG. 4 is a diagram showing a configuration of a table 211 that stores information on low-volatile explosives.
FIG. 5 is a diagram showing the relationship between the ion mass of a highly volatile or low volatile explosive component and its strength.
6 is a flowchart showing an explosive detection process in a measurement unit 20. FIG.
FIG. 7 is a diagram showing a relationship between measurement time axes and ion signal intensities of a high volatile group and a low volatile group.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Material collection paper introduction | transduction mechanism, 2 ... Material collection paper heating furnace, 3 ... Material collection paper insertion detection circuit, 4 ... Component gas flow path, 5 ... Ion source, 6 ... Corona discharge electrode, 7 ... Differential exhaust part, DESCRIPTION OF SYMBOLS 8 ... Electrostatic lens, 9 ... Pump, 10 ... Differential vacuum pump, 11 ... Vacuum pump, 12 ... Back pump, 13 ... Vacuum chamber, 14 ... Quadrupole analyzer tube, 15 ... Secondary electron multiplier, 16 DESCRIPTION OF SYMBOLS ... Signal amplifier, 17 ... Electrostatic lens voltage control part, 18 ... Quadrupole analyzer control part, 19 ... A / D converter, 20 ... Measurement part.

Claims (8)

A method for detecting explosives adhering to a material collection paper,
The types of explosives to be detected are classified in advance into groups of highly volatile explosives and low volatility explosives according to the ease of evaporation during heating, and each explosive contained in each group For a plurality of components having different ion masses that appear when ionized are classified into main components and subcomponents according to intensity, and stored in a table.
When detecting explosives, refer to the table above.
Until the detection of the introduction of the substance collection form,
The peak of the main component of the explosive contained in the group of highly volatile explosives is detected, and when the peak of the main component is detected, the measurement of the subcomponent corresponding to the main component is repeated and the number of measurements is Accumulate,
When the introduction of the material collection sheet is detected, the rejection determination and the type determination of the explosives classified into the group of highly volatile explosives are performed based on the result of the measurement,
If the number of measurements does not reach the specified number of measurements,
The peak of the main component contained in the low-volatile explosives is detected, and when the peak of the main component is detected, the sub-component corresponding to the main component is measured,
By determining whether or not the explosives are classified into the low volatility explosive group based on the measurement result,
An explosive detection method characterized by detecting a plurality of types of explosives having different volatility. The explosive detection method according to claim 1,
For the explosives included in the high volatile explosive group and the explosives included in the low volatile explosive group, the threshold for detecting the peak of the main component is not set in advance on the material collection sheet. An explosive detection method characterized in that the explosive detection method is set based on the signal intensity of background noise of ions acquired without being attached. The explosive detection method according to claim 1,
As a result of peak detection of the main component of explosives included in the low volatility explosive group, if the peak of the main component is not detected,
A method for detecting explosives, characterized by measuring a group of highly volatile explosives again. The explosive detection method according to claim 1, wherein a plurality of components are selected as the subcomponents and stored in the table.
A method for detecting an explosive material, characterized in that when a peak of a main component is detected, measurement is started for the plurality of subcomponents. A device for detecting explosives adhering to a material collection paper,
A heating furnace for heating the material collection paper, a detection circuit for detecting that the material collection paper has been introduced into the heating furnace, and an ionization unit for ionizing explosives heated and vaporized in the heating furnace; And a measurement unit for measuring the signal intensity of the ions,
The measurement unit has a memory for storing information on explosives to be detected,
When multiple types of explosives to be detected are classified in advance into groups of high volatile explosives and low volatility explosives according to the ease of evaporation during heating, and each explosive is ionized A plurality of components having different ion masses appearing in categorized into main components and subcomponents according to intensity, creating a table and storing them in the memory,
When detecting explosives,
The measuring unit is
Until the detection circuit detects the introduction of the substance collection sheet, the peak of the main component of the explosives classified into the highly volatile explosives group with reference to the table stored in the memory repeatedly. When the main component peak is detected, the sub-component corresponding to the main component is measured and the number of measurements is accumulated.
When the detection circuit detects the introduction of the substance collection sheet, the measurement unit determines whether or not the explosives are classified into the highly volatile explosive group based on the result of the measurement. Done
If the number of measurements does not reach the specified number of measurements,
Detect the peak of the main component of the explosive contained in the low volatility explosive group, and if the main component peak is detected, measure the subcomponent corresponding to the main component,
By determining whether or not the explosives are classified into the low-volatile explosive group based on the result of the measurement,
An explosive detection device for detecting explosives of different types of volatility. The explosive detection device according to claim 5,
The threshold for detecting the main component peaks of the explosives classified into the high volatile explosives group and the explosives classified into the low volatile explosives group is not set in advance on the material collection sheet. An explosive detection device characterized in that it is set based on the signal intensity of background noise of ions acquired without being attached. The explosive detection device according to claim 5,
As a result of peak detection of the main component of explosives included in the low volatility explosive group, if the peak of the main component is not detected,
An explosive detection device characterized by measuring a group of highly volatile explosives again. The explosive detection device according to claim 5 , wherein a plurality of components are selected as the subcomponents,
An explosives detection device, wherein, when a peak of a main component is detected, measurement is started for the plurality of subcomponents.

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