CN115639264A - SO in insulating gas 2 Atmospheric negative ion detection device and using method thereof - Google Patents

Abstract

_The present invention is a kind of SO2 in the insulating gas Atmospheric pressure negative ion detection device and using method thereof, the _SO2 atmospheric pressure negative ion detection device in the insulating gas comprises a syringe pump, a switch valve, a sampling bottle, an insulating layer and a time-of-flight mass spectrometer, wherein the flight The ionization source used by the time mass spectrometer is ⁶³ Ni, and the ionization method is chemical ionization under atmospheric pressure. The sample purge gas connected to the switch valve and the gas inlet carries the insulating gas sample into the ionization source for efficient ionization and analysis. There is an insulation layer on the outside of the bottle, a ceramic heating layer is placed inside the insulation layer, and a heater connection line is installed on the outside to connect to the power supply. After the power is turned on, the rapid heating and cooling can be achieved through thermal radiation, which is used for heating and heat preservation, so as to dry the moisture. The moisture drying effect is good and can Effectively prevent moisture from entering the power supply of the time-of-flight mass spectrometer and affect the detection results. The measurement method is simple, the sample consumption is low, the analysis speed is fast, and the detection sensitivity can reach the ppb level.

Description

An atmospheric pressure anion detection device for SO2 in insulating gas and its application method

technical field

The invention relates to the technical field of detection equipment and a detection method for decomposition products of insulating gas in electrical equipment, in particular to an atmospheric _- pressure negative ion detection device for SO2 in insulating gas and a method for using the same.

Background technique

SF ₆ gas has a history of one hundred years. It is an artificial inert gas synthesized by two French chemists, Moissan and Lebeau, in 1900. Around 1940, the US military used it for the Manhattan Project. Commercially available in 1947. Currently SF ₆ gas is mainly used in the power industry. SF ₆ gas is used in 4 types of electrical equipment as insulation and/or arc extinguishing; SF ₆ circuit breakers and GIS (here refers to sulfur hexafluoride closed combination electrical appliances, internationally known as "gas insulated switchgear"), SF ₆ load switchgear, SF ₆ insulated transmission pipeline, SF ₆ transformer and SF ₆ insulated substation. Of the SF ₆ gas, 80% is used for high and medium voltage power equipment. Sulfur hexafluoride has good electrical insulation performance and excellent arc extinguishing performance. Its electric strength is 2.5 times that of nitrogen under the same pressure, its breakdown voltage is 2.5 times that of air, and its arc extinguishing ability is 100 times that of air. It is a new generation of ultra-high voltage insulating dielectric material superior to that between air and oil. Sulfur hexafluoride is used in circuit breakers, high-voltage transformers, gas-enclosed combined capacitors, high-voltage transmission lines, transformers, etc. due to its good insulation performance and arc-extinguishing performance. Electronic-grade high-purity sulfur hexafluoride is an ideal electronic etchant, which is widely used in the field of microelectronics technology. As a refrigerant in the refrigeration industry, the refrigeration range can be between -45°C and 0°C. The electrical industry uses its high dielectric strength and good arc extinguishing performance as an insulating material for high-voltage switches, large-capacity transformers, high-voltage cables and gases.

Atmospheric pressure chemical ionization source is a soft ionization technology that produces few fragment ions, relatively simple mass spectrum and high sensitivity, so it can be used as an ionization source for on-line monitoring mass spectrometers. Time-of-flight mass spectrometer has the advantages of fast analysis speed, high sensitivity and full-spectrum scanning, and the combination of atmospheric pressure chemical ionization source can realize high-sensitivity online detection of various mixed samples. In recent years, power grid safety accidents have occurred frequently, which has had a great impact on the national economy and power transmission safety. Therefore, the monitoring of insulating gas is conducive to the safe operation of power supply equipment. Most of the discharge products produced by SF ₆ during discharge contain F atoms, and F atoms have a strong electron-withdrawing ability. Most of the discharge products of SF ₆ have high electronegativity, which is more conducive to detection in negative ion mode. Therefore, an atmospheric pressure negative ion ionization source combined with a time-of-flight mass spectrometer was used to detect SO ₂ , a typical decomposition product in the decomposition products of SF ₆ discharge. Through the qualitative and quantitative analysis of SO ₂ , timely discovery of hidden troubles inside electrical equipment has guiding significance for the normal operation of power grid equipment.

The patent of the present invention uses a syringe pump to carry a small amount of gas samples to the ionization area of the time-of-flight mass spectrometer for detection, and the atmospheric pressure negative ion source can realize efficient ionization and analysis of SO ₂ . Moreover, the device and method have low sample consumption and fast analysis speed.

Contents of the invention

Aiming at the deficiencies in the prior art, the object of the present invention is to provide a kind of measuring method simple, sample consumption is low, the analysis speed SO in the insulating gas _The atmospheric pressure anion detection device and using method thereof.

In order to achieve the above object, the technical scheme that the present invention adopts is as follows: a kind of SO in the insulating gas _The atmospheric pressure negative ion detection device of SO in the insulating gas _The atmospheric pressure negative ion detection device includes: syringe pump, switch valve, sampling bottle, Insulation layer, time-of-flight mass spectrometer; the outlet of the syringe pump directly extends into the inside of the sampling bottle;

The left and right sides of the sampling bottle are respectively provided with an air inlet and an air outlet, and the air inlet is provided with the switch valve for opening and closing the air inlet, and one end of the air outlet directly extends into the inside the ionization region of the time-of-flight mass spectrometer;

The outer wall of the sample injection bottle is provided with a thermal insulation layer, and the thermal insulation layer is equipped with a ceramic heating layer, and a heater connecting line is arranged on the outside to connect to the power supply. to heat and keep warm;

The ionization source adopted by the time-of-flight mass spectrometer is ⁶³ Ni, and the ionization method is chemical ionization under atmospheric pressure.

Further, the volume of the syringe used in the syringe pump is 1-5 ml, and the linear speed is 1 ml/min, so as to inject the insulating gas sample into the sampling bottle at a uniform speed.

Further, the gas inlet is connected to the gas outlet of the sample purge gas; the length of the gas outlet is controlled at 45-55cm.

Further, the sample purge gas is selected from any one of N ₂ , clean air, and He.

Further, the thickness of the ceramic heating layer in the thermal insulation layer is 10-20 mm.

The present invention also provides a method for using an atmospheric pressure _anion detection device for SO in an insulating gas, comprising the following steps:

Step S1, inject the insulating gas sample into the syringe pump, and inject the insulating gas sample into the sampling bottle at a uniform speed through the syringe pump;

Step S2, simultaneously opening the on-off valve to open the air inlet, and the sample purge gas is sent into the sampling bottle through the air inlet;

Step S3, opening the insulation layer provided outside the sampling bottle, heating and insulating the insulating gas samples in the sampling bottle and the gas outlet, so as to play a role of drying and prevent moisture from entering the ionization source of the time-of-flight mass spectrometer internal;

In step S4, the sample purge gas carries the insulating gas sample to the ionization region of the time-of-flight mass spectrometer through the gas outlet for ionization analysis.

Further, the flow rate of the sample purge gas in the step S2 is controlled at 35-40 ml/min.

Further, in the step S3, the temperature inside the sampling bottle is controlled at 75-85°C; the temperature inside the gas outlet is controlled at 85-95°C.

Further, in the step S3, the temperature difference between the sampling bottle and the gas outlet is controlled at 8-12°C.

Further, in the step S4, ion peaks with mass-to-charge ratios of 83 and 112 are collected.

The beneficial effect of the present invention is: a kind of SO in the insulating gas of the present invention _The atmospheric pressure negative ion detection device and its use method, SO in the insulating gas _The atmospheric pressure negative ion detection device comprises a syringe pump, a switch valve, a sampling bottle, an insulating layer and Time-of-flight mass spectrometer, wherein the ionization source used by the time-of-flight mass spectrometer is ⁶³ Ni, and the ionization method is chemical ionization under atmospheric pressure. The insulating gas sample is carried into the ionization source through the switch valve and the sample purge gas connected to the gas inlet, and the High-efficiency ionization and analysis. There is an insulation layer outside the sampling bottle, which is used to heat and keep the insulating gas sample. The insulation layer is equipped with a ceramic heating layer, and the external heater is connected to the power supply. After the power is turned on, the surface of the ceramic heating layer is heated. Through Thermal radiation realizes rapid heating and cooling, which is used for heating and heat preservation, thereby drying moisture. The moisture drying effect is good, which can effectively prevent moisture from entering the power supply of the time-of-flight mass spectrometer and affect the detection results. The measurement method is simple, the sample consumption is low, and the analysis speed Fast, the detection sensitivity can reach the ppb level.

The present invention is an atmospheric-pressure negative ion detection device for SO2 in insulating gas and its use method. The length of the gas outlet is controlled, and the temperature of the sampling bottle and the gas outlet is controlled at the same time, which is equivalent to drying the insulating gas sample once in the sampling bottle, and then Perform secondary drying on the insulating gas sample at the gas outlet, the drying effect of the insulating gas sample is better, further prevent moisture from entering the power supply of the time-of-flight mass spectrometer, and the detection accuracy is higher; control the sampling bottle and the gas outlet The temperature difference is better, the drying effect of the insulating gas sample is better, and the moisture is further prevented from entering the power supply of the time-of-flight mass spectrometer, and the detection accuracy is higher.

Description of drawings

Fig. 1 is the structural representation of device of the present invention;

In the figure: 1. Syringe pump; 2. On-off valve; 3. Injection bottle; 4. Insulation layer; 5. Time-of-flight mass spectrometer; 31. Air inlet; 32. Air outlet.

Fig. 2 is a graph of detection results in Example 1 of the present invention.

Detailed ways

The following examples can help those skilled in the art to understand the present invention more comprehensively, but the present invention cannot be limited in any way.

The present invention is a kind of SO2 in insulating gas Atmospheric pressure anion detection device and using method thereof, described sample purge gas selects any one in N ₂ , clean air, He; The sample purge gas selected in the following examples is N ₂ .

The specific embodiment one of device of the present invention:

An atmospheric pressure _anion detection device for SO2 in an insulating gas, the atmospheric pressure negative ion detection device for SO2 in an insulating gas comprises: a syringe pump 1, a switch valve ₂ , a sampling bottle 3, an insulating layer 4, and a time-of-flight mass spectrometer 5; The outlet of the syringe pump 1 directly extends into the inside of the sampling bottle 3; the syringe used in the syringe pump 1 has a volume range of 1-5 ml and a linear velocity of 1ml/min, which is used to uniformly speed the insulating gas sample Inject in the described sampling bottle 3;

The left and right sides of the sampling bottle 3 are respectively provided with an air inlet 31 and an air outlet 32, the air inlet 31 is provided with the switch valve 2 for opening and closing the air inlet 31, and the air outlet One end of 32 directly extends into the inside of the ionization region of the time-of-flight mass spectrometer 5; the gas inlet 31 is connected to the gas outlet of the sample purge gas; the length of the gas outlet 32 is controlled at 50 cm;

The outer wall of the sample injection bottle 3 is provided with a thermal insulation layer 4, a ceramic heating layer is arranged inside the thermal insulation layer 4, and a heater connection line is arranged on the outside to connect to the power supply. cooling for heating and heat preservation; the thickness of the ceramic heating layer in the heat preservation layer 4 is 15 mm;

The ionization source adopted by the time-of-flight mass spectrometer 5 is ⁶³ Ni, and the ionization method is chemical ionization under atmospheric pressure.

The specific embodiment two of device of the present invention:

An atmospheric pressure _anion detection device for SO2 in an insulating gas, the atmospheric pressure negative ion detection device for SO2 in an insulating gas comprises: a syringe pump 1, a switch valve ₂ , a sampling bottle 3, an insulating layer 4, and a time-of-flight mass spectrometer 5; The outlet of the syringe pump 1 directly extends into the inside of the sampling bottle 3; the syringe used in the syringe pump 1 has a volume range of 1-5 ml and a linear velocity of 1ml/min, which is used to uniformly speed the insulating gas sample Inject in the described sampling bottle 3;

The left and right sides of the sampling bottle 3 are respectively provided with an air inlet 31 and an air outlet 32, the air inlet 31 is provided with the switch valve 2 for opening and closing the air inlet 31, and the air outlet One end of 32 directly extends into the inside of the ionization region of the time-of-flight mass spectrometer 5; the gas inlet 31 is connected to the gas outlet of the sample purge gas; the length of the gas outlet 32 is controlled at 25 cm;

The outer wall of the sample injection bottle 3 is provided with a thermal insulation layer 4, a ceramic heating layer is arranged inside the thermal insulation layer 4, and a heater connection line is arranged on the outside to connect to the power supply. cooling for heating and heat preservation; the thickness of the ceramic heating layer in the heat preservation layer 4 is 15 mm;

The ionization source adopted by the time-of-flight mass spectrometer 5 is ⁶³ Ni, and the ionization method is chemical ionization under atmospheric pressure.

The specific embodiment three of the device of the present invention:

An atmospheric pressure _anion detection device for SO2 in an insulating gas, the atmospheric pressure negative ion detection device for SO2 in an insulating gas comprises: a syringe pump 1, a switch valve ₂ , a sampling bottle 3, an insulating layer 4, and a time-of-flight mass spectrometer 5; The outlet of the syringe pump 1 directly extends into the inside of the sampling bottle 3; the syringe used in the syringe pump 1 has a volume range of 1-5 ml and a linear velocity of 1ml/min, which is used to uniformly speed the insulating gas sample Inject in the described sampling bottle 3;

The left and right sides of the sampling bottle 3 are respectively provided with an air inlet 31 and an air outlet 32, the air inlet 31 is provided with the switch valve 2 for opening and closing the air inlet 31, and the air outlet One end of 32 directly extends into the inside of the ionization region of the time-of-flight mass spectrometer 5; the gas inlet 31 is connected to the gas outlet of the sample purge gas; the length of the gas outlet 32 is controlled at 75 cm;

The outer wall of the sample injection bottle 3 is provided with a thermal insulation layer 4, a ceramic heating layer is arranged inside the thermal insulation layer 4, and a heater connection line is arranged on the outside to connect to the power supply. cooling for heating and heat preservation; the thickness of the ceramic heating layer in the heat preservation layer 4 is 15 mm;

The ionization source adopted by the time-of-flight mass spectrometer 5 is ⁶³ Ni, and the ionization method is chemical ionization under atmospheric pressure.

The difference between Embodiment 1 to Embodiment 3 of the device of the present invention is only the length of the gas outlet 32. The device in Embodiment 1 to Embodiment 3 is used to carry out the SF ₆ insulating gas drying experiment. During the experiment, further The temperature in the sample bottle 1 is controlled at 75-85°C; the temperature in the gas outlet 32 is controlled at 95-105°C. SF ₆ insulating gas drying experiments show that the length of the gas outlet is controlled at 45-55 cm, and the SF ₆ insulation The gas drying effect is the best, which can effectively prevent moisture from entering the power supply of the time-of-flight mass spectrometer, and the detection accuracy is higher.

Embodiment ₁ : Utilize the inventive device in the specific embodiment one to carry out SF ₆ in insulating gas SO detection experiment

_A method for using an atmospheric pressure negative ion detection device for SO in an insulating gas, comprising the following steps:

Step S1, inject the insulating gas sample into the syringe pump 1, and inject the insulating gas sample into the sample bottle 3 at a uniform speed through the syringe pump 1; the syringe used in the syringe pump 1 has a volume range of 1-5ml and a linear speed of 1ml/min;

Step S2, open the on-off valve 2 at the same time to open the air inlet 31, and the sample purge gas is sent into the sampling bottle 3 through the air inlet 31; the flow rate of the sample purge gas is controlled at 35ml/min;

Step S3, opening the insulation layer 4 provided outside the sampling bottle 3, heating and insulating the insulating gas samples in the sampling bottle 3 and the gas outlet 32, so as to dry and prevent moisture from entering the time-of-flight Inside the ionization source of the mass spectrometer 5; the temperature in the described sampling bottle 3 is controlled at 75°C; the temperature in the described gas outlet 32 is controlled at 85°C; The temperature difference of gas port 32 is controlled at 10°C;

Step S4, the sample purge gas passes through the gas outlet 32 to carry the insulating gas sample to the ionization region of the time-of-flight mass spectrometer 5 for ionization analysis, SO ₂ will form two ion peaks with mass-to-charge ratios of 83 and 112, And the signal strength is high, so ion peaks with mass-to-charge ratios of 83 and 112 are collected; atmospheric pressure negative ions are used to detect SO ₂ in SF ₆ insulating gas with a concentration of 100ppm. The detection results are shown in Figure 2, and the negative ion detection mode can be clearly seen Under normal conditions, SO ₂ will form two ion peaks with mass-to-charge ratios of 83 and 112, and the signal intensity is high. Calculated according to S/N=3:1, its sensitivity can reach the ppb level.

Embodiment ₂ : Utilize the inventive device in the specific embodiment one to carry out SF ₆ in insulating gas SO detection experiment

_A method for using an atmospheric pressure negative ion detection device for SO in an insulating gas, comprising the following steps:

Step S1, inject the insulating gas sample into the syringe pump 1, and inject the insulating gas sample into the sample bottle 3 at a uniform speed through the syringe pump 1; the syringe used in the syringe pump 1 has a volume range of 1-5ml and a linear speed of 1ml/min;

Step S2, open the on-off valve 2 at the same time to open the air inlet 31, and the sample purge gas is sent into the sampling bottle 3 through the air inlet 31; the flow rate of the sample purge gas is controlled at 40ml/min;

Step S3, opening the insulation layer 4 provided outside the sampling bottle 3, heating and insulating the insulating gas samples in the sampling bottle 3 and the gas outlet 32, so as to dry and prevent moisture from entering the time-of-flight Inside the ionization source of the mass spectrometer 5; the temperature in the described sampling bottle 3 is controlled at 85°C; the temperature in the described gas outlet 32 is controlled at 95°C; The temperature difference of gas port 32 is controlled at 10°C;

Step S4, the sample purge gas passes through the gas outlet 32 to carry the insulating gas sample to the ionization region of the time-of-flight mass spectrometer 5 for ionization analysis, SO ₂ will form two ion peaks with mass-to-charge ratios of 83 and 112, And the signal strength is high, so the ion peaks with mass-to-charge ratios of 83 and 112 are collected; using atmospheric pressure negative ions to detect SO ₂ in SF ₆ insulating gas, calculated according to S/N=3:1, the sensitivity can reach ppb level.

Embodiment ₃ : Utilize the inventive device in the specific embodiment one to carry out SF ₆ in insulating gas SO detection experiment

_A method for using an atmospheric pressure negative ion detection device for SO in an insulating gas, comprising the following steps:

Step S1, inject the insulating gas sample into the syringe pump 1, and inject the insulating gas sample into the sample bottle 3 at a uniform speed through the syringe pump 1; the syringe used in the syringe pump 1 has a volume range of 1-5ml and a linear speed of 1ml/min;

Step S2, open the on-off valve 2 at the same time to open the air inlet 31, and the sample purge gas is sent into the sampling bottle 3 through the air inlet 31; the flow rate of the sample purge gas is controlled at 37ml/min;

Step S3, opening the insulation layer 4 provided outside the sampling bottle 3, heating and insulating the insulating gas samples in the sampling bottle 3 and the gas outlet 32, so as to dry and prevent moisture from entering the time-of-flight Inside the ionization source of the mass spectrometer 5; the temperature in the described sampling bottle 3 is controlled at 78°C; the temperature in the described gas outlet 32 is controlled at 90°C; The temperature difference of gas port 32 is controlled at 12°C;

Step S4, the sample purge gas passes through the gas outlet 32 to carry the insulating gas sample to the ionization region of the time-of-flight mass spectrometer 5 for ionization analysis, SO ₂ will form two ion peaks with mass-to-charge ratios of 83 and 112, And the signal strength is high, so the ion peaks with mass-to-charge ratios of 83 and 112 are collected; using atmospheric pressure negative ions to detect SO ₂ in SF ₆ insulating gas, calculated according to S/N=3:1, the sensitivity can reach ppb level.

The present invention is an atmospheric pressure _anion detection device for SO2 in an insulating gas and a method for using the same. _The atmospheric pressure negative ion detection device for SO2 in an insulating gas comprises a syringe pump 1, a switch valve 2, a sampling bottle 3, an insulating layer 4, and a time-of-flight mass spectrometer instrument 5, wherein the ionization source used by the time-of-flight mass spectrometer 5 is ⁶³ Ni, the ionization method is chemical ionization under atmospheric pressure, and the sample purge gas connected to the switch valve 2 and the gas inlet 31 carries the insulating gas sample into the ionization source, For high-efficiency ionization and analysis, the sample bottle 3 is provided with an insulating layer 4 for heating and insulating the insulating gas sample. The insulating layer 4 is equipped with a ceramic heating layer, and the external heater is connected to the power supply. After the power is turned on, the ceramic heating layer plate The surface heats up, realizes rapid heating and cooling through thermal radiation, and is used for heating and heat preservation to dry moisture. The moisture drying effect is good, and it can effectively prevent moisture from entering the power supply of the time-of-flight mass spectrometer 5 and affect the detection results. The measurement method is simple and the sample consumption Low volume, fast analysis speed, detection sensitivity can reach ppb level; controlling the length of the gas outlet 32, and simultaneously controlling the temperature of the sampling bottle 3 and the gas outlet 32, is equivalent to drying the insulating gas sample once in the sampling bottle 3, Then the insulating gas sample is dried again at the gas outlet 32, the drying effect of the insulating gas sample is better, further preventing moisture from entering the power supply of the time-of-flight mass spectrometer, and the detection accuracy is higher; the control of the sampling bottle 3 and the The temperature difference of the gas outlet 32 is improved, the drying effect of the insulating gas sample is better, and moisture is further prevented from entering the power supply of the time-of-flight mass spectrometer, and the detection accuracy is higher.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. SO in insulating gas ₂ The atmospheric pressure negative ion detection device of (1), characterized in that SO in the insulating gas ₂ The atmospheric pressure negative ion detection device includes: the device comprises an injection pump (1), a switch valve (2), a sample injection bottle (3), a heat insulation layer (4) and a flight time mass spectrometer (5); the outlet of the injection pump (1) directly extends into the interior of the sampling bottle (3);

the left side and the right side of the sample inlet bottle (3) are respectively provided with a gas inlet (31) and a gas outlet (32), the gas inlet (31) is provided with the switch valve (2) for opening and closing the gas inlet (31), and one end of the gas outlet (32) directly extends into an ionization region of the time-of-flight mass spectrometer (5);

the outer wall of the sampling bottle (3) is provided with a heat insulation layer (4), a ceramic heating layer is distributed in the heat insulation layer (4), a heater connecting line is arranged outside the heat insulation layer and connected with a power supply, the ceramic heating layer generates heat after being electrified, and rapid heating and cooling are realized through thermal radiation and are used for heating and heat insulation;

the time-of-flight mass spectrometer (5) adopts an ionization source of ⁶³ Ni, the ionization mode is chemical ionization under atmospheric pressure.

2. SO in insulating gas according to claim 1 ₂ The atmospheric pressure negative ion detection device is characterized in that the range of an injector adopted by the injection pump (1) is 1-5ml, and the linear speed is 1ml/min, so that an insulating gas sample is injected into the sample injection bottle (3) at a constant speed.

3. According to claim1 an insulating gas of ₂ The atmospheric pressure negative ion detection device is characterized in that the air inlet (31) is connected with an air outlet of sample purge gas; the length of the air outlet (32) is controlled to be 45-55 cm.

4. SO in insulating gas according to claim 3 ₂ The atmospheric pressure negative ion detection device is characterized in that N is selected as the sample purge gas ₂ Any one of clean air and He.

5. SO in insulating gas according to claim 1 ₂ The atmospheric pressure negative ion detection device is characterized in that the thickness of the ceramic heating layer in the heat insulation layer (4) is 10-20 mm.

6. SO in insulating gas according to claim 1 ₂ The use method of the atmospheric pressure negative ion detection device is characterized by comprising the following steps:

s1, injecting an insulating gas sample into an injection pump (1), and injecting the insulating gas sample into a sample injection bottle (3) at a constant speed through the injection pump (1);

s2, simultaneously opening the switch valve (2) to open the air inlet (31), and sending sample purging gas into the sample inlet bottle (3) through the air inlet (31);

s3, opening a heat insulation layer (4) arranged outside the sample inlet bottle (3), heating and insulating the insulating gas samples in the sample inlet bottle (3) and the gas outlet (32), drying, and preventing moisture from entering the ionization source of the time-of-flight mass spectrometer (5);

and S4, carrying the insulating gas sample to an ionization region of the time-of-flight mass spectrometer (5) through the gas outlet (32) by using the sample purging gas for ionization analysis.

7. SO in insulating gas according to claim 1 ₂ Of the atmospheric negative ion detection deviceThe use method is characterized in that the flow rate of the sample purge gas in the step S2 is controlled to be 35-40 ml/min.

8. SO in insulating gas according to claim 1 ₂ The method for using the atmospheric pressure negative ion detection device is characterized in that the temperature in the sampling bottle (3) in the step S3 is controlled to be 75-85 ℃; the temperature in the air outlet (32) is controlled to be 85-95 ℃.

9. SO in insulating gas according to claim 8 ₂ The application method of the atmospheric pressure negative ion detection device is characterized in that the temperature difference between the sample inlet bottle (3) and the gas outlet (32) in the step S3 is controlled to be 8-12 ℃.

10. SO in insulating gas according to claim 1 ₂ The method for using an atmospheric pressure negative ion detector in (1), wherein ion peaks having mass-to-charge ratios of 83 to 112 are collected in step S4.

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