JP2005300288A - Gas analysis method, gas analysis apparatus, and inspection apparatus using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To analyze gases continuously for a long time by eliminating the need for an adsorbent even when substances except moisture contents in gases to be measured are to be detected. <P>SOLUTION: A mass spectroscope 2 comprises an ionizing part 3 for introducing a gas to be measured, and a mass spectroscopic part 4 for analyzing ions ionized by the ionizing part 3. The ionizing part 3 comprises a primary ionizing chamber 3a, and a secondary ionizing chamber 3b. Steam generated by a steam generating device 6 is introduced to the primary ionizing chamber 3a with a carrier gas from a cylinder 12. Steam generated by a steam generating device 5 is introduced to the secondary ionizing chamber 3b with a carrier gas from a cylinder 11 in addition to a sample gas from a sample cylinder 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas analysis method using a mass spectrometer such as an atmospheric pressure ionization mass spectrometer, a gas analyzer, and an inspection apparatus using the same.

  Conventionally, using a mass spectrometer having an ionization part into which a measurement target gas is introduced and a mass analysis part for analyzing ions ionized by the ionization part, such as an atmospheric pressure ionization mass spectrometer, a measurement target gas (sample Gas) is being analyzed.

  In such a gas analysis method, as disclosed in Patent Document 1 below, when a substance other than moisture in the measurement target gas is to be detected, the moisture at the ppb level contained in the measurement target gas is an interfering substance. It is known that the detection sensitivity becomes worse.

  For this reason, conventionally, when a substance other than moisture in the measurement target gas is to be detected, the measurement target after removing moisture from the measurement target gas in advance with an adsorbent such as silica gel or molecular sieves and removing the moisture. Gas was introduced into the ionization part of the mass spectrometer. Patent Document 1 discloses an example in which silica gel is used as an adsorbent.

As described above, in the gas analysis method using the mass spectrometer, when a substance other than moisture in the measurement target gas is used as a detection target, it is a conventional technical common sense that moisture is previously removed from the measurement target gas. It was.
Japanese Patent Laid-Open No. 6-74939

  However, in the conventional gas analysis method, if a predetermined amount of moisture is adsorbed to the adsorbent, the adsorbent cannot adsorb moisture. Therefore, before the adsorbent cannot adsorb moisture, gas analysis is performed. And the adsorbent had to be dried.

  Therefore, in the conventional gas analysis method, since the period in which the adsorbent can adsorb moisture is relatively short, continuous gas analysis for a long time is impossible. In addition, it takes time to dry the adsorbent, which is inconvenient.

  The present invention has been made in view of such circumstances, and even when a substance other than moisture in a measurement target gas is a detection target, it is not necessary to use an adsorbent, and it is continuous for a long time. An object of the present invention is to provide a gas analysis method, a gas analyzer, and an inspection apparatus using the same, which are capable of gas analysis.

  As a result of the inventor's research, the gas to be measured is measured by positively introducing water vapor into the ionization part of the mass spectrometer and increasing the water concentration in the ionization part, in contrast to the above-described conventional technical common knowledge of water removal. It has been found that substances other than moisture (for example, organic substances) can be detected with high sensitivity.

This is considered to be based on the following principle from the experimental results described later. That is, moisture at a concentration of ppb or ppm deprives the ion of the parent ion (primary ion) in the ionization part, and does not pass the charge to the substance to be detected by that amount (that is, the amount of the parent ion) The charge exchange reaction in which only the charge moves from the target substance to the detection target substance), and the target substance is not ionized, so that the substance is not detected by the mass spectrometer, and the detection sensitivity is considered to decrease. . On the other hand, when a higher concentration of water is introduced into the ionization part, a large amount of water cluster ions (H ₂ O) _n H ⁺ are generated, and proton H ⁺ is detected from some water cluster ions. reaction (hereinafter, referred to as protonation reaction.) is added to the material occurs, because the detection target substance to be ionized in a state in which the H ⁺ is added, the substance was added H ⁺ mass analyzer It is considered that the detection sensitivity is increased as the state is detected.

  The present invention has been made based on such new findings by the present inventors. That is, in order to solve the above-described problem, the gas analysis method according to the first aspect of the present invention includes a mass analysis unit including an ionization unit into which a measurement target gas is introduced and a mass analysis unit that analyzes ions ionized by the ionization unit. In addition to the measurement object gas, water vapor is introduced into the ionization unit using an apparatus.

  According to the first aspect, since water vapor is introduced into the ionization section of the mass spectrometer in addition to the measurement target gas, the moisture concentration in the ionization section is increased. Therefore, according to the above-described knowledge, a substance (for example, organic substance) to be detected other than moisture in the measurement target gas can be detected with high sensitivity without previously removing water from the measurement target gas. Therefore, according to this first aspect, it is not necessary to use an adsorbent, and a long-term continuous gas analysis is possible. Further, since water vapor is specially introduced, there is no danger of explosion or the like, and handling is easy.

  The gas analysis method according to the second aspect of the present invention is the gas analysis method according to the first aspect, wherein the highest peak among the respective peaks of ion intensity in the mass spectrum obtained by the mass spectrometer is 37, 55, 73 and 91 Water vapor is introduced into the ionization part so as to be obtained at any mass-to-charge ratio.

If the moisture concentration of the ionization part is low, the substance to be inspected in the measurement target gas cannot be detected with high sensitivity according to the principle described above. On the other hand, if the water concentration in the ionization part is too high, the peak of the ion intensity of the cluster ion having a large n among the water cluster ions (H ₂ O) _n H ⁺ is large in the mass spectrum obtained by the mass spectrometer. Therefore, it becomes difficult to determine the peak of the ion intensity according to the substance to be inspected in the measurement target gas. On the other hand, as in the second aspect, in the mass spectrum, the highest peak among the peaks of ionic strength is obtained at any mass-to-charge ratio of 37, 55, 73 and 91. If water vapor is introduced into the ionization unit, the water concentration in the ionization unit is optimized, and the detection target substance in the measurement target gas can be detected with higher sensitivity.

  “37” is the mass-to-charge ratio of n = 2 moisture cluster ions, “55” is the mass-to-charge ratio of n = 3 moisture cluster ions, and “73” is the n = 4 moisture cluster ion mass. The charge ratio, “91”, is the mass-to-charge ratio of n = 5 moisture cluster ions.

  In the gas analysis method according to the third aspect of the present invention, in the first or second aspect, the amount of water vapor introduced into the ionization unit is controlled so that the water concentration in the ionization unit is substantially constant. It is.

  When the water concentration in the ionization portion changes, the efficiency of proton addition changes as described above. Therefore, when the water concentration in the ionization portion is made substantially constant as in the third aspect, the detection target substance in the measurement target gas is stabilized. This is preferable because it can be detected.

  A gas analysis method according to a fourth aspect of the present invention is the gas analysis method according to any one of the first to third aspects, wherein water vapor is introduced into the ionization section so that a moisture concentration in the ionization section is 1% or more. It is.

  When the water concentration in the ionization part is set to 1% or more as in the fourth aspect, the above-described proton addition reaction occurs relatively significantly, which is preferable.

  In the gas analysis method according to the fifth aspect of the present invention, in the first or second aspect, the ionization section includes a primary ionization chamber and a secondary ionization chamber, and the primary ionization chamber and the secondary ionization chamber are provided. Water vapor is introduced into either one or both.

  In the fifth aspect, when the ionization section has a primary ionization chamber and a secondary ionization chamber, the destination of water vapor introduction into the ionization section is clearly shown. In the first to fourth aspects, the ionization section may have only a single ionization chamber.

  In the gas analysis method according to the sixth aspect of the present invention, in the fifth aspect, the primary ionization chamber and the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber are substantially constant, respectively. Water vapor is introduced into one or both of the secondary ionization chambers.

  According to the sixth aspect, since the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber are made substantially constant, the detection target substance in the measurement target gas can be detected more stably. ,preferable.

  The gas analysis method according to a seventh aspect of the present invention is the gas analysis method according to the sixth aspect, wherein the primary ionization chamber and the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber are substantially the same. Water vapor is introduced into one or both of the secondary ionization chambers.

  In the sixth aspect, as in the seventh aspect, the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber may be substantially the same, or the water concentrations of both may be different.

  In the gas analysis method according to the eighth aspect of the present invention, in any one of the fifth to seventh aspects, one or both of the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber is 1. %, Water vapor is introduced into one or both of the primary ionization chamber and the secondary ionization chamber.

  According to the eighth aspect, when either one or both of the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber are set to 1% or more as in the fourth embodiment, the proton addition reaction described above is performed. This is preferable because it occurs relatively remarkably.

  In the gas analysis method according to the ninth aspect of the present invention, in any one of the first to eighth aspects, the measurement target gas is a gas sampled directly without using a sampling container, or sampling. It is a gas stored in a sampling container such as a cylinder or a sampling bag, or a gas obtained on the downstream side of the container when a carrier gas is passed through a container in which a predetermined object is stored. Is.

  The ninth aspect exemplifies the measurement target gas from the viewpoint of the supplier, but the measurement target gas is not limited to these examples.

  A gas analyzer according to a tenth aspect of the present invention includes a mass spectrometer having an ionization section into which a measurement target gas is introduced and a mass analysis section that analyzes ions ionized by the ionization section, and the measurement in the ionization section. And an introduction means for introducing water vapor in addition to the target gas.

  The gas analyzer according to the eleventh aspect of the present invention is the gas analyzer according to the tenth aspect, wherein the introduction means has the highest peak of 37, 55 among the peaks of the ion intensity in the mass spectrum obtained by the mass spectrometer. , 73 and 91, water vapor is introduced into the ionization part so as to be obtained at any mass-to-charge ratio.

  In the gas analyzer according to the twelfth aspect of the present invention, in the tenth or eleventh aspect, a detection means for directly or indirectly detecting the moisture concentration in the ionization section, and a detection signal from the detection means. And a control means for controlling the amount of water vapor introduced into the ionization section by the introduction means so that the water concentration in the ionization section becomes substantially constant.

  The gas analyzer according to a thirteenth aspect of the present invention is the gas analyzer according to any one of the tenth to twelfth aspects, wherein the introduction means is disposed in the ionization section so that a moisture concentration in the ionization section is 1% or more. Water vapor is introduced.

  In the gas analyzer according to the fourteenth aspect of the present invention, in the tenth or eleventh aspect, the ionization section has a primary ionization chamber and a secondary ionization chamber, and the introduction means includes the primary ionization chamber and the ionization chamber. Water vapor is introduced into one or both of the secondary ionization chambers.

  The gas analyzer according to the fifteenth aspect of the present invention is the gas analyzer according to the thirteenth or fourteenth aspect, wherein the first ionization means for directly or indirectly detecting the water concentration in the primary ionization chamber, and the secondary ionization. Based on detection signals from the second detection means for directly or indirectly detecting the moisture concentration in the room and the first and second detection means, the moisture concentration in the primary ionization chamber and the secondary ionization chamber Control means for controlling the amount of water vapor introduced into one or both of the primary ionization chamber and the secondary ionization chamber by the introduction means so that the water concentration of each becomes substantially constant. is there.

  In the gas analyzer according to the sixteenth aspect of the present invention, in the fifteenth aspect, the control means is configured so that the moisture concentration in the primary ionization chamber and the moisture concentration in the secondary ionization chamber are substantially the same. The amount of water vapor introduced into one or both of the primary ionization chamber and the secondary ionization chamber by the introduction means is controlled.

  The gas analyzer according to a seventeenth aspect of the present invention is the gas analyzer according to any one of the fourteenth to sixteenth aspects, wherein the introduction means is one of a water concentration in the primary ionization chamber and a water concentration in the secondary ionization chamber. Water vapor is introduced into one or both of the primary ionization chamber and the secondary ionization chamber so that one or both are 1% or more.

  A gas analyzer according to an eighteenth aspect of the present invention is the gas analyzer according to any one of the tenth to seventeenth aspects, wherein the measurement target gas is a gas sampled directly without using a sampling container. It is a gas stored in a sampling container such as a cylinder or a sampling bag, or a gas obtained on the downstream side of the container when a carrier gas is passed through a container in which a predetermined object is stored. Is.

  The gas analyzers according to the tenth to eighteenth aspects implement the gas analysis methods according to the first to ninth aspects, respectively.

  An inspection apparatus according to a nineteenth aspect of the present invention includes a container in which an object to be inspected is housed, and the gas analyzer according to any one of the tenth to seventeenth aspects, and allows carrier gas to pass through the container. The gas obtained on the downstream side of the container when it is caused to flow is used as the measurement object gas.

  According to the nineteenth aspect, the substance attached to the inspection object or volatilized from the inspection object is used as the detection object in the measurement target gas, so that the inspection object is inspected for quality or quality. It can be performed. For example, when a food item such as an agricultural product is used as the inspection object, the state of adhesion of the agricultural chemical to the food item can be inspected. Further, for example, when the inspection object is clothing, the presence or amount of harmful substances in the clothing can be inspected. According to the nineteenth aspect, since the gas analyzer according to any one of the tenth to seventeenth aspects is used, it is not necessary to use an adsorbent, and long-term continuous inspection is possible. It becomes.

  According to the present invention, even when a substance other than moisture in the gas to be measured is to be detected, it is not necessary to use an adsorbent, and a long-term continuous gas analysis is possible. A gas analyzer and an inspection apparatus using the same can be provided.

  Hereinafter, a gas analysis method, a gas analyzer, and an inspection apparatus using the same according to the present invention will be described with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a schematic configuration diagram showing a gas analyzer 1 according to a first embodiment of the present invention.

  The gas analyzer 1 according to the present embodiment includes a mass spectrometer 2. The mass spectrometer 2 includes an ionization unit 3 into which a measurement target gas (sample gas) is introduced, and a mass analysis unit 4 that analyzes ions ionized by the ionization unit 3. In the present embodiment, an atmospheric pressure ionization mass spectrometer is used as the mass spectrometer 2. Moreover, in this Embodiment, the ionization part 3 has the primary ionization chamber 3a which ionizes the introduce | transduced gas primarily, and the secondary ionization chamber 3b in which measurement object gas is introduce | transduced. In the primary ionization chamber 3a, a discharge needle 3c that is ionized by corona discharge is disposed as an ionization means. An atmospheric pressure ionization mass spectrometer of the type in which the ionization unit 3 includes the primary ionization chamber 3a and the secondary ionization chamber 3b as described above is known as disclosed in, for example, Japanese Patent Laid-Open No. 6-310091.

  The outlets of the steam generators 5 and 6 are connected to the inlet of the primary ionization chamber 3a and the inlet of the secondary ionization chamber 3b, respectively. In the middle of the piping between the inlet of the primary ionization chamber 3a and the inlet of the secondary ionization chamber 3b, an outlet of a flow rate regulator 7 that adjusts the flow rate of the measurement target gas is connected.

  A measurement target gas is introduced into the introduction port of the flow rate regulator 7. In the example shown in FIG. 1, the measurement target gas accommodated in the sampling cylinder 8 is introduced into the introduction port of the flow rate regulator 7.

Examples of the substance to be detected in the measurement target gas include benzene (C ₆ H ₆ ), trichlorethylene (ClCH═CCl ₂ ), tetrachloroethylene (CCl ₂ = CCl ₂ ), dichloromethane (CH ₂ Cl ₂ ), chloroform (CHCl). ₃ ), ethanol (CH ₃ OH), methanol (C ₂ H ₅ OH), propanol (C ₃ H ₇ OH) and the like.

  The water vapor generators 5 and 6 generate water vapor by heating the water contained therein with the heaters 5a and 6a. The inlets of the steam generators 5 and 6 are connected to the outlets of the flow controllers 9 and 10, respectively. The inlets of the flow controllers 9 and 10 are connected to the outlets of the high-pressure cylinders 11 and 12 that contain a carrier gas for transporting water vapor, respectively. The high pressure cylinders 11 and 12 have pressure reducing valves 11a and 12a at their discharge ports, respectively. As the carrier gas accommodated in the high pressure cylinders 11 and 12, for example, air, nitrogen, argon, helium, or the like can be used.

  The discharge port of the primary ionization chamber 3 a is connected to the introduction port of the flow rate regulator 13. The outlet of the flow controller 13 is open to the atmosphere. The discharge port of the secondary ionization chamber 3 b is connected to the intake port of the decompression pump 15 via the pressure regulator 14. The exhaust port of the decompression pump 15 is open to the atmosphere.

  As a detecting means for detecting the moisture concentration in the primary ionization chamber 3a, a hygrometer 16 for detecting the humidity of the gas discharged from the discharge port of the primary ionization chamber 3a is provided. Further, a hygrometer 17 for detecting the humidity of the gas discharged from the discharge port of the secondary ionization chamber 3b is provided as a detection means for detecting the moisture concentration in the secondary ionization chamber 3b. Based on the detection signals from the hygrometers 16 and 17, the control unit 18 sets a fixed set value (primary ionization chamber 3a) in which the water concentration in the primary ionization chamber 3a and the water concentration in the secondary ionization chamber 3b are set. And the secondary ionization chamber 3b may be the same or different.) By controlling the energization amount to the heaters 5a and 5b, respectively, As a result, the amount of water vapor introduced into the primary ionization chamber 3a and the amount of water vapor introduced into the secondary ionization chamber 3b are respectively controlled.

  Here, it is preferable that the set value of the moisture concentration in the primary ionization chamber 3a and the set value of the moisture concentration in the secondary ionization chamber 3b can be adjusted as appropriate. And these setting values are the masses of any one of 37, 55, 73, and 91 in which the highest peak of each peak of ion intensity in the mass spectrum obtained by the mass spectrometer 2 is the reason already explained. It is preferable to set so as to obtain the charge ratio. These set values are preferably set so that the moisture concentration in the primary ionization chamber 3a and the moisture concentration in the secondary ionization chamber 3b are 1% or more for the reason already described.

  Although it is preferable to introduce water vapor into both ionization chambers 3a and 3b as in the present embodiment, water vapor may be introduced into only one of the ionization chambers.

  According to the present embodiment, the carrier gas from the cylinder 12 is depressurized by the pressure reducing valve 12a, the flow rate is adjusted by the flow rate regulator 10, and the primary ionization chamber 3a is accompanied by the water vapor generated by the water vapor generator 6. Then, it is exhausted through the flow rate regulator 10. As a result, the carrier gas and water vapor are primarily ionized by corona discharge in the primary ionization chamber 3a.

  On the other hand, the gas to be measured in the sampling cylinder 8 is introduced into the secondary ionization chamber 3b after the flow rate is adjusted by the flow rate regulator 7. Further, the carrier gas from the cylinder 11 is depressurized by the pressure reducing valve 11a, the flow rate is adjusted by the flow rate regulator 9, and the secondary gas in addition to the measurement target gas is accompanied by the water vapor generated by the water vapor generating device 5. It is introduced into the ionization chamber 3b. Ions and the like obtained in the primary ionization chamber 3a are mixed with the gas to be measured and water vapor, and the above-described proton addition reaction or the like occurs. The pressure of the gas introduced into the secondary ionization chamber 3 b is adjusted by the pressure regulator 14. Then, the gas introduced into the secondary ionization chamber 3b is exhausted through the pressure regulator 14 and the decompression pump 15.

  Then, the ions obtained in the secondary ionization chamber 3b are analyzed by the mass analyzer 4 to obtain a mass spectrum. From this mass spectrum, the detection target substance in the measurement target gas can be detected, and thereby the measurement target gas can be analyzed.

  According to this embodiment, since water vapor is introduced into the ionization unit 3 of the mass spectrometer 2 in addition to the measurement target gas, the moisture concentration in the ionization unit 3 is increased. Therefore, according to the above-described knowledge, a substance to be detected other than moisture in the measurement target gas can be detected with high sensitivity without previously removing water from the measurement target gas. Therefore, according to the present embodiment, it is not necessary to use an adsorbent, and long-term continuous gas analysis is possible. Further, since water vapor is specially introduced, there is no danger of explosion or the like, and handling is easy.

  As the measurement target gas, the measurement target gas stored in the sampling cylinder 8 is used in the example shown in FIG. 1, but the gas stored in the sampling bag 20 may be used as shown in FIG. A gas that is directly sampled without being used may be used as a measurement target gas. In the latter case, the directly sampled gas may be an atmospheric gas such as the atmosphere, or may be exhaled as shown in FIG. In the example shown in FIG. 3, a collector 60 that collects exhaled air is connected to the inlet of the flow controller 7. When directly sampling atmospheric gas such as the atmosphere, for example, a collector that collects atmospheric gas or the like is connected to the inlet of the flow controller 7 or a nozzle that collects atmospheric gas or the like at the tip. A sampling tube having a tip at the tip may be connected to the inlet of the flow rate regulator 7. In addition, when using sampling containers, such as the sampling cylinder 8 and the sampling bag 20, it cannot be overemphasized that the gas accommodated in the said container as measurement object gas may be arbitrary gas other than atmospheric gas, such as air | atmosphere, and exhalation .

  [Second Embodiment]

  FIG. 4 is a schematic configuration diagram showing an inspection apparatus according to the second embodiment of the present invention. 2, elements that are the same as or correspond to elements in FIG. 1 are given the same reference numerals, and redundant descriptions thereof are omitted.

  The inspection apparatus according to the present embodiment includes the gas analyzer 1 described above, a container 31 in which an inspection object 30 is accommodated, and a high-pressure cylinder 32 in which a carrier gas to be passed through the container 31 is accommodated. Yes. The discharge port of the high-pressure cylinder 32 is connected to the introduction port of the container 31. The high-pressure cylinder 32 has a pressure reducing valve 32a at its discharge port. The discharge port of the container 31 is connected to the introduction port of the flow controller 7, and the carrier gas supplied from the high pressure cylinder 32 flows through the container 31 containing the inspection object 30, and then the flow rate is adjusted as the measurement target gas. It is introduced into the inlet of the vessel 7.

  According to the present embodiment, the quality, quality, etc., of the inspection object 30 is determined by setting the substance attached to the inspection object 30 or volatilizing from the inspection object 30 as the detection object in the measurement object gas. Can be inspected.

  For example, when a food product such as an agricultural product is used as the inspection object 30, it is possible to inspect the state of adhesion of the agricultural chemical to the food product. For example, when the inspection object 30 is clothing, the presence or amount of harmful substances in the clothing can be inspected. And according to this Embodiment, since the gas analyzer 1 mentioned above is used, it is not necessary to use adsorption agent, and a continuous inspection for a long time is attained.

  [Third Embodiment]

  FIG. 5 is a schematic configuration diagram showing a gas analyzer 41 according to the third embodiment of the present invention. 5, elements that are the same as or correspond to those in FIG. 1 are given the same reference numerals, and redundant descriptions thereof are omitted.

  The gas analyzer 41 according to the present embodiment is different from the gas analyzer 1 according to the first embodiment only in the points described below.

  That is, in the present embodiment, instead of the atmospheric pressure ionization mass spectrometer 2 in which the ionization unit 3 in FIG. 1 has a primary ionization chamber 3a and a secondary ionization chamber 3b, an ionization unit 43 is a single ionization chamber. An atmospheric pressure ionization mass spectrometer 42 of the type having only 44a is used. In FIG. 5, 43c is a discharge needle disposed in the ionization chamber 44a, and 44 is a mass spectrometer.

  Accordingly, in the present embodiment, the elements 6, 10, 12, 13, 16 in FIG. 1 are removed. The outlet of the steam generator 5 is connected to the inlet of the ionization chamber 44a. The inlet of the pressure regulator 14 is connected to the outlet of the ionization chamber 44a. Based on the detection signal from the hygrometer 17, the control unit 18 controls the energization amount to the heater 5 a so that the moisture concentration in the ionization chamber 44 a becomes a set constant value, thereby generating water vapor. The amount of water vapor generated by the apparatus 5 and thus the amount of water vapor introduced into the ionization chamber 44a is controlled.

  Here, it is preferable that the set value of the moisture concentration in the ionization chamber 44a can be adjusted as appropriate. And, for the reason already explained, this set value is the mass charge of any one of 37, 55, 73 and 91 in which the highest peak of each ion intensity peak in the mass spectrum obtained by the mass spectrometer 2 is obtained. It is preferable to set the ratio so that the ratio is obtained. Further, this set value is preferably set so that the moisture concentration in the ionization chamber 44a is 1% or more for the reason already described.

  Also in this embodiment, the same advantages as those in the first embodiment can be obtained. In the inspection apparatus shown in FIG. 4, a gas analyzer 41 may be used instead of the gas analyzer 1.

  [Experiment 1]

  Experiment 1 corresponds to a conventional gas analysis method. In this experiment 1, high-purity nitrogen gas from which moisture was removed to about 1 ppb with a molecular sieve was used at a flow rate of 1000 cc / min using an atmospheric pressure ionization mass spectrometer similar to the atmospheric pressure mass spectrometer 42 in FIG. The sample was introduced into the ionization chamber 44a, and the mass spectrum was obtained with the pressure in the ionization chamber 44a being almost atmospheric pressure. This mass spectrum is shown in FIG.

In FIG. 6, each peak of mass-to-charge ratio 28, 42, 56 is a peak of nitrogen (N ₂ ⁺ , N ₃ ⁺ , N ₄ ⁺ ). The peak with a mass to charge ratio of 18 is the peak of water.

  [Experiment 2]

  Experiment 2 corresponds to a conventional gas analysis method. In Experiment 2, an atmospheric pressure ionization mass spectrometer similar to the atmospheric pressure mass spectrometer 42 in FIG. 5 is used, and a gas obtained by adding 10 ppb of benzene to high-purity nitrogen gas is removed to about 1 ppb with molecular sieves. The gas was introduced into the ionization chamber 44a at a flow rate of 1000 cc / min, and the pressure in the ionization chamber 44a was almost atmospheric pressure to obtain a mass spectrum. This mass spectrum is shown in FIG.

  In a gas having a low water concentration, only a charge is transferred from nitrogen ions to benzene by a charge exchange reaction in which only the charge moves, and a peak of mass-to-charge ratio 78 corresponding to the mass of benzene is obtained as shown in FIG. Detected.

  [Experiment 3]

  Experiment 3 and Experiments 4 to 6 described later correspond to the gas analysis method according to the present invention.

  In this experiment 3, it corresponds to an atmospheric pressure ionization mass spectrometer similar to the atmospheric pressure mass spectrometer 2 in FIG. 1, and the element water vapor generators 5 and 6, hygrometers 16 and 17, and the control unit 18 in FIG. 1. The gas obtained by adding water vapor in the order of% to high-purity air is introduced into the primary ionization chamber 3a and the secondary ionization chamber 3b at a flow rate of 1000 cc / min, respectively, and the pressures in the ionization chambers 3a and 3b are approximately A mass spectrum was obtained at atmospheric pressure. At this time, the control unit 18 controlled the relative humidity detected by the hygrometers 16 and 17 to be a constant value of about 50%. This mass spectrum is shown in FIG.

As shown in FIG. 8, peaks of nitrogen and oxygen, which are components of high-purity air, are not detected at all, and ions of water with a mass-to-charge ratio of 18 to which proton H ⁺ is not added and mass-to-charge ratios of 19, 37, 55, 73, 91, 109, 127, 145, 163, 181, 199, and 217, (H ₂ O) _n H ⁺ moisture cluster ions are detected.

  [Experiment 4]

  In this experiment 4, an atmospheric pressure ionization mass spectrometer similar to the atmospheric pressure mass spectrometer 2 in FIG. 1 and the element water vapor generators 5 and 6, the hygrometers 16 and 17, and the control unit 18 in FIG. The gas in which% order water vapor is added to high-purity air is introduced into the primary ionization chamber 3a at a flow rate of 1000 cc / min, and the gas in which% order water vapor and 10 ppb benzene are added to high-purity air is 1000 cc. Was introduced into the secondary ionization chamber 3b at a flow rate of / min, and the mass spectra were obtained with the pressure in the ionization chambers 3a and 3b being substantially atmospheric pressure. At this time, the control unit 18 controlled the relative humidity detected by the hygrometers 16 and 17 to be a constant value of about 50%. This mass spectrum is shown in FIG.

Proton H ⁺ is added to benzene from water vapor ions having a large mass number, and benzene is in a state where proton H ⁺ is added, as shown in FIG. 9, at a mass-to-charge ratio of benzene mass number + 1 = 79. Detected at the peak.

  [Experiment 5]

  In this experiment 5, an atmospheric pressure ionization mass spectrometer similar to the atmospheric pressure mass spectrometer 2 in FIG. 1 and the element water vapor generators 5 and 6, hygrometers 16 and 17, and the control unit 18 in FIG. The gas obtained by adding% order steam to high-purity air is introduced into the primary ionization chamber 3a at a flow rate of 1000 cc / min, and% order steam and 10 ppb DBP (phthalic acid-n-- Butyl gas was introduced into the secondary ionization chamber 3b at a flow rate of 1000 cc / min, and the pressure in the ionization chambers 3a and 3b was set to substantially atmospheric pressure to obtain a mass spectrum. At this time, the control unit 18 controlled the relative humidity detected by the hygrometers 16 and 17 to be a constant value of about 50%. This mass spectrum is shown in FIG.

Proton H ⁺ is added to DBP from water vapor ions having a large mass number, and DBP is in a state where proton H ⁺ is added, as shown in FIG. 10, at a mass-to-charge ratio of DBP mass number + 1 = 279. Detected at the peak.

  [Experiment 6]

  In this experiment 6, an atmospheric pressure ionization mass spectrometer similar to the atmospheric pressure mass spectrometer 2 in FIG. 1 and the element water vapor generators 5 and 6, the hygrometers 16 and 17, and the control unit 18 in FIG. A gas obtained by adding% -order water vapor to high-purity air is introduced into the primary ionization chamber 3a at a flow rate of 1000 cc / min, and a gas obtained by adding% -order water vapor and 10 ppb ethanol to high-purity air is 1000 cc. Was introduced into the secondary ionization chamber 3b at a flow rate of / min, and the mass spectra were obtained with the pressure in the ionization chambers 3a and 3b being substantially atmospheric pressure. At this time, the control unit 18 controlled the relative humidity detected by the hygrometers 16 and 17 to be a constant value of about 50%. This mass spectrum is shown in FIG.

Proton H ⁺ is added to ethanol from water vapor ions having a large mass number. Furthermore, since ethanol is hydrophilic, (H ₂ O) _n H ⁺ moisture cluster ions are also added to ethanol. as a state in which cluster ions of ^{H +} protons and water is added, as shown in FIG. 11, the mass number of the ethanol ^{_{+1+ (H 2 O) n H}} + mass to charge ratio of (n = 1 in the case 51, n = The peak is detected at 69 in the case of 2, 87 in the case of n = 3, and 105) in the case of n = 4.

As can be seen from Experiments 4 to 6, hydrophobic benzene or the like has its own mass number + 1 mass-to-charge ratio, and hydrophilic alcohol or the like has its own mass number + 1 + (H ₂ O) _n mass number. A peak is observed at the mass to charge ratio.

  From the experimental results described above, the water concentration is increased by positively introducing water vapor into the ionization part of the mass spectrometer and increasing the water concentration in the ionization part, contrary to the above-described conventional technical common water removal. Due to the accompanying proton addition reaction, it has been found that substances other than moisture in the gas to be measured can be detected with high sensitivity.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

It is a schematic block diagram which shows the gas analyzer by the 1st Embodiment of this invention. It is a figure which shows the other example of the supply method of the measuring object gas with respect to the gas analyzer by the 1st Embodiment of this invention. It is a figure which shows the further another example of the supply method of the measuring object gas with respect to the gas analyzer by the 1st Embodiment of this invention. It is a schematic block diagram which shows the inspection apparatus by the 2nd Embodiment of this invention. It is a schematic block diagram which shows the gas analyzer by the 3rd Embodiment of this invention. It is a mass spectrum which shows the experimental result by the conventional gas analysis method. It is a mass spectrum which shows the other experimental result by the conventional gas analysis method. It is a mass spectrum which shows the experimental result by the gas analysis method of this invention. It is a mass spectrum which shows the other experimental result by the gas analysis method of this invention. It is a mass spectrum which shows the further another experimental result by the gas analysis method of this invention. It is a mass spectrum which shows the further another experimental result by the gas analysis method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 Gas analyzer 2 Mass spectrometer 3,43 Ionization part 3a Primary ionization room 3b Secondary ionization room 5,6 Water vapor generator 8 Sampling cylinder 16, 17 Hygrometer 18 Control part 20 Sampling bag 30 Inspection object 31 Container 43a Ionization chamber

Claims (19)

  Using a mass spectrometer having an ionization section into which a measurement target gas is introduced and a mass analysis section for analyzing ions ionized by the ionization section, water vapor is introduced into the ionization section in addition to the measurement target gas. Gas analysis method.   In the mass spectrum obtained by the mass spectrometer, water vapor is supplied to the ionization section so that the highest peak among the peaks of ionic strength is obtained at any mass-to-charge ratio of 37, 55, 73 and 91. The gas analysis method according to claim 1, wherein the gas analysis method is introduced.   The gas analysis method according to claim 1 or 2, wherein the amount of water vapor introduced into the ionization unit is controlled so that the water concentration in the ionization unit is substantially constant.   The gas analysis method according to any one of claims 1 to 3, wherein water vapor is introduced into the ionization unit so that a moisture concentration in the ionization unit is 1% or more. The ionization section has a primary ionization chamber and a secondary ionization chamber;
The gas analysis method according to claim 1 or 2, wherein water vapor is introduced into one or both of the primary ionization chamber and the secondary ionization chamber.   Water vapor is introduced into one or both of the primary ionization chamber and the secondary ionization chamber so that the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber are substantially constant, respectively. The gas analysis method according to claim 5.   Water vapor is introduced into one or both of the primary ionization chamber and the secondary ionization chamber so that the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber are substantially the same. The gas analysis method according to claim 6.   Water vapor is supplied to one or both of the primary ionization chamber and the secondary ionization chamber so that one or both of the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber is 1% or more. The gas analysis method according to claim 5, wherein the gas analysis method is introduced.   The measurement target gas is a gas that is directly sampled without using a sampling container, a gas that is stored in a sampling container such as a sampling cylinder or a sampling bag, or a predetermined object is stored inside The gas analysis method according to any one of claims 1 to 8, wherein the gas analysis method is a gas obtained on the downstream side of the container when a carrier gas is passed through the prepared container. A mass spectrometer having an ionization section into which a measurement target gas is introduced and a mass spectrometry section that analyzes ions ionized by the ionization section;
Introducing means for introducing water vapor into the ionization unit in addition to the measurement target gas;
A gas analyzer characterized by comprising:   The introduction means is configured so that the highest peak among the peaks of ionic strength in a mass spectrum obtained by the mass spectrometer is obtained at any mass-to-charge ratio of 37, 55, 73, and 91. The gas analyzer according to claim 10, wherein water vapor is introduced into the ionization unit. Detection means for directly or indirectly detecting the moisture concentration in the ionization unit;
Control means for controlling the amount of water vapor introduced into the ionization section by the introduction means so that the moisture concentration in the ionization section is substantially constant based on the detection signal from the detection means;
The gas analyzer according to claim 10 or 11, further comprising:   The gas analyzer according to any one of claims 10 to 12, wherein the introduction unit introduces water vapor into the ionization unit so that a moisture concentration in the ionization unit is 1% or more. The ionization section has a primary ionization chamber and a secondary ionization chamber;
The gas analyzer according to claim 10 or 11, wherein the introduction means introduces water vapor into one or both of the primary ionization chamber and the secondary ionization chamber. First detection means for directly or indirectly detecting the moisture concentration in the primary ionization chamber;
A second detection means for directly or indirectly detecting the water concentration in the secondary ionization chamber;
Based on the detection signals from the first and second detection means, the primary ionization chamber by the introduction means so that the moisture concentration in the primary ionization chamber and the moisture concentration in the secondary ionization chamber are respectively substantially constant. And control means for controlling the amount of water vapor introduced into one or both of the secondary ionization chambers;
The gas analyzer according to claim 13 or 14, further comprising:   The control means is configured such that one or both of the primary ionization chamber and the secondary ionization chamber by the introduction means are set so that the moisture concentration in the primary ionization chamber and the moisture concentration in the secondary ionization chamber are substantially the same. The gas analyzer according to claim 15, wherein the amount of water vapor introduced into the water is controlled.   The introduction means includes either the primary ionization chamber or the secondary ionization chamber so that one or both of the water concentration in the primary ionization chamber and the water concentration in the secondary ionization chamber is 1% or more. The gas analyzer according to any one of claims 14 to 16, wherein water vapor is introduced into both or both.   The measurement target gas is a gas that is directly sampled without using a sampling container, a gas that is stored in a sampling container such as a sampling cylinder or a sampling bag, or a predetermined object is stored inside The gas analyzer according to any one of claims 10 to 17, wherein the gas analyzer is a gas obtained on the downstream side of the container when a carrier gas is passed through the container. (Inspection equipment)
A container in which an object to be inspected is stored;
A gas analyzer according to any one of claims 10 to 17,
With
An inspection apparatus characterized in that a gas obtained on the downstream side of the container when the carrier gas is caused to flow through the container is the measurement target gas.

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