This method is suitable for the determination of trace nitrogen in electronic grade argon. This method can be used to simultaneously determine the content of methane, carbon monoxide and carbon dioxide in it. The determination range is 1 to 50 ppm. SJ 2804.1-1987 Method for determination of trace nitrogen in electronic grade argon - variable temperature concentration chromatography (I) SJ2804.1-1987 Standard download decompression password: www.bzxz.net
This method is suitable for the determination of trace nitrogen in electronic grade argon. This method can be used to simultaneously determine the content of methane, carbon monoxide and carbon dioxide in it. The determination range is 1 to 50 ppm.

Standard of the Ministry of Electronic Industry of the People's Republic of China on the determination of trace nitrogen in electronic grade argon
Variable temperature concentration chromatography ()
SJ2B04.1-87
This method is suitable for the determination of trace amounts in electronic grade argon. This method can be used to simultaneously determine the contents of methane, carbon monoxide and carbon dioxide, with a determination range of 1 to 50 ppm. 1 Principle of the method
1.1 This method is variable temperature concentration chromatography. The carrier gas carries the sample through the chromatographic column to separate the components and then enters the thermal conductivity detector.
1.2 The thermal conductivity detector is made based on the principle that the thermal conductivity of other components mixed in the carrier gas changes. When the sample and the carrier gas enter the thermal conductivity cell together, due to the different thermal conductivities of the two, the temperature of the thermistor changes, causing its resistance to change accordingly, and the output signal is measured by the Wheatstone bridge.
1.3 In order to improve the sensitivity, this method adopts the concentration technology, that is, under low temperature conditions, the impurities are enriched on the concentrator to increase the injection amount. The molecular sieve has a greater adsorption capacity for nitrogen at a temperature of about -80°C. 1.4 Chromatographic analysis uses argon as the carrier gas.
2 Instruments and materials
2.1 Gas chromatograph:
a. Thermal conductivity detector
b. Chromatographic column: stainless steel inner diameter 4mm×3m with 5A molecular sieve, 80-100 months. c. Recorder or microprocessor: 0~1mv. 2.2 Carrier gas: high-purity argon.
2.3 Glass or metal four-way concentrator tube, with 3g5A molecular sieve inside. 2.4 Wet gas flowmeter and low-temperature thermometer. 2.5 Cold source, liquid ammonia plus anhydrous ethanol adjusted to -80°C. 3 Flow chart and test conditions
3.1 See Figure 1 for the flow chart.
Sampler
3.2 Test conditions
a. Column temperature: room temperature
b. Detection chamber: room temperature
c. Vaporization chamber: room temperature
Chromatographic column
Recorder
Flow chart for determination of trace cyanide in electronic grade hydrogen
15~35℃;
15~35℃
15~35℃ ;
Issued by the Ministry of Electronics Industry on May 18, 1987
Calibrator
Implemented on January 1, 1987
d. Attenuation:
e. Paper speed 5mm/min;
f. Bridge current: 65mA;
SJ2804.1—87
g. Carrier gas flow rate: 40~60m1/min.
4 Operation steps
Quartz cloth
Molecular sieve
Variable temperature concentration sampling device
Four-way piston concentration sampling tube
A: Sample gas cylinder
B: Needle valve
C: Four-way piston concentration sampling tube
D: Cold source
E: Wet gas flowmeter
Quartz cloth
Molecular sieve
SJ2804.1--87
4.1 European purge gas path uses hard connection or ground connection system according to Figure 2, and the concentration tube is closed. Open the argon cylinder, the flow rate is about 800m1/min, the time is about 0.5h, reduce the flow rate to about 500m1/min, open the four-way piston (see Figure 3), let the argon gas pass through the molecular sieve in the sampler to purge the air, the time is about half an hour, and further adjust the flow rate to about 200m1/min. 4.2 Sampling Slowly put on the cold source and start counting the time. When the wet gas flowmeter indicates that the gas volume has reached the requirement, turn off the gas source and remove the cold source at the same time. When the gas volume discharged from the sampling tube is about 100m1, immediately close the piston and remove the sampling tube. 4.3 Injection Heat desorb the concentrator in room temperature water or a hair dryer for 3c5min, connect the concentrator and the chromatograph injection port with a hard connection, exhaust the air peak first, open the four-way piston of the concentrator to inject, wait for the sample peak to be completed, and use a trace amount of air as a standard sample.
5 Calculation results
Assume that the volume of the standard air sample is V1, μ1;
the nitrogen peak area of ​​the standard air sample is A1, mm2
the total volume of the sample is V, 1
the nitrogen peak area of ​​the sample is A2, mm2
the coefficient of 79% is the percentage of nitrogen in the air; the nitrogen content in fluorine is -www.bzxz.net
2.×79%×V1×
6 Analytical precision
The arithmetic mean of three parallel determinations is the determination result, and the relative deviation is not more than ±15%. 7 Test report
7.1 The test report should include the following contents:
time, place, unit, date;
b. Sampling method and number;
type and model of instrument used:
d. Test conditions and results;
e. Analyst signature.
8 Precautions
8.1 The system must be connected by hard connection or ground connection to prevent leakage. The ground connection and four-way piston must be lubricated and sealed with silicone grease to fit tightly.
8.2 The chlorine gas cylinder must be adjusted with a needle valve to adjust the flow rate, otherwise the dead volume is large and the gas path is not easy to purge clean. 8.3 The concentration tube should be filled with as much 5A molecular sieve as possible so that nitrogen can be completely adsorbed. 8.4 Temperature has a great influence on concentrated sampling, and the temperature must be controlled to be less than -82℃. 9 See Figure 4 for a typical chromatogram.
Additional instructions:
Air standard
5mm/min
SJ2804.1-87
Typical chromatogram for determination of trace nitrogen in electronic grade argon This standard was proposed by the Clean Technology Society of the Chinese Institute of Electronics. Sponsored by the Standardization Institute of the Ministry of Electronics Industry. This standard was drafted and revised by Wang Mingan of the 878th Factory of the Ministry of Electronics Industry, Zhao Changchun of the Standardization Institute of the Ministry of Electronics Industry, and Yin Enhua of the Semiconductor Institute of the Chinese Academy of Sciences.
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