This standard specifies the method for determining trace amounts of argon, nitrogen and krypton in oxygen. This standard is applicable to the determination of trace amounts of argon, nitrogen and krypton in pure oxygen, high-purity oxygen, oxygen used in the electronics industry and other gaseous and liquid oxygen. GB/T 14605-1993 Determination of trace amounts of argon, nitrogen and krypton in oxygen - Gas chromatography method GB/T14605-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of trace argon, nitrogen and krypton in oxygen
Gas chromatographic method
Determination of trace argon, nitrogen and krypton inoxygen-Gas chromatographic method1 Subject content and scope of applicationbzxz.net
This standard specifies the method for the determination of trace argon, nitrogen and krypton in oxygen GB/T14605-93
This standard is applicable to the determination of trace argon, nitrogen and krypton in gaseous and liquid oxygen such as pure oxygen, high-purity oxygen and gas oxygen for the electronics industry. 2 Reference standards
GB2723 General safety rules for sampling of industrial chemical productsGB4844
GB 6680
General rules for sampling of liquid chemical products
GB 6681
General rules for sampling of gaseous chemical products
GB 7445 Hydrogen
3 Summary of methods
Gas chromatography is used to determine trace amounts of argon, nitrogen and krypton in oxygen. This method uses a deoxidizer to first remove oxygen, and then the detected components argon, nitrogen and nitrogen are separated by chromatography and enter the detector. The response value output by the detector is proportional to the content of the component to be measured within a certain range. The response value of the component to be measured is compared with the response value of the same component with a known concentration in the standard mixed gas for quantification. 4 Instruments
According to the content range of fluorine, nitrogen and krypton and the detection capability of the instrument, select the following gas chromatographs: a. Gas chromatograph with thermal conductivity detector (TCD), the detection capability of argon and nitrogen should be about one order of magnitude lower than the content of the component to be measured, and the linear dynamic range should not be less than 10°. It is suitable for the determination of trace fluorine and nitrogen content in oxygen gas used in the electronics industry. b. Gas chromatograph with ammonia ionization detector (HID) or photoionization detector (PID), the detection capability of argon, nitrogen and nitrogen should be about one order of magnitude lower than the content of the component to be measured, and the linear dynamic range should not be less than 103. It is suitable for the determination of trace fluorine, nitrogen and krypton content in pure oxygen, high-purity oxygen and oxygen gas used in the electronics industry. The main gas flow of the chromatograph is shown in the figure below: Approved by the State Bureau of Technical Supervision on August 26, 1993 230
Implemented on July 1, 1994
5 Determination conditions
5.1 Chromatographic column
GB/T 14605--93
Schematic diagram of the main gas flow of the chromatograph
1 Sample valve: 2 Deoxidation valve; 3 Separation peach:
4 Detector
A stainless steel column with a length of about 2m and an inner diameter of about 4mm. It is filled with 5A (or 13X) molecular sieves of 250~400um. The separation degree of fluorine, nitrogen and nitrogen should be greater than 1 at the full place of the column. 5.2 Deoxidation column
A glass column or stainless steel column with a length of about 2m and an inner diameter of about 4mm, and a 401 deoxidizer with a length of 400~800um. It is permitted to use other types of deoxidizers with the same deoxidation capacity as specified in this standard. 5.3 Carrier gas
When using a chromatograph with a thermal conductivity detector (TCD), use high-purity hydrogen as the carrier gas. High-purity hydrogen should comply with the provisions of GB7115. The fluorine content in the total gas shall not exceed 10% of the content of the component to be tested. High-purity ammonia can also be used as carrier gas. The high purity should comply with the provisions of (GB1811) When using a chromatograph with a cyanide ionization detector (HID) or a photoionization detector (PID). Use high-purity hydrogen as carrier gas. High-purity nitrogen should comply with the provisions of (GB1841844). When the actual content of argon, nitrogen and nitrogen in high-purity ammonia exceeds or approaches the content of the component to be measured, the high-purity ammonia should be purified before use. Ensure that the content of fluorine, nitrogen and chlorine in the carrier gas should be less than 10% of the content of the component to be measured. The flow base of the carrier gas is selected according to the instrument manual and the separation of the components to be measured. 5.4 Instrument operating parameters
The operating parameters of the instrument are selected according to the instrument manual and the requirements of this standard. 5.5 Sample volume
When using a chromatograph with a thermal conductivity detector. Sample volume When the sample volume is 5-10mL and a chromatograph with an ammonia ionization or photoionization detector is used, the sample gas volume is 1-5mL. 5.6 Detector temperature: room temperature.
5.7 Chromatographic column temperature: room temperature or selected according to the separation requirements. 5.8 Deoxygenation column temperature: room temperature or selected according to the deoxidizer requirements. 6 Preparation
6.1 Preparation of chromatographic column
Activate 250-400m 5A (or 13X) molecular sieves in a muffle furnace at about 500C for 4-6h, take them out and cool them to room temperature in a desiccator, and put them into a clean and dry chromatographic column for use. Or use a chromatographic column filled with 250-400m 5A (or 13X) molecular sieves for about 231
GB/T14605-93
35 Pass dry fluorine gas (or nitrogen, hydrogen, ammonia) at 0C for activation for 6 to 8 hours, and set aside after cooling. 6.2 Preparation of deoxidation column
The preparation of 401 deoxidation column is carried out as follows: pass hydrogen at a flow rate of 40 to 80 mL/min into the deoxidation column filled with 400800μm 401 deoxidizer in an electric furnace and increase the temperature. Keep the temperature constant at 100C, 200℃, 300℃, and 400℃ for 1 hour each. Keep the temperature constant at 450℃ for 8 hours. Stop heating when the average amount of hydrogen passed per gram of deoxidizer is 1.5 to 21.0, and continue to pass hydrogen until it cools to room temperature. Immediately seal the activated green deoxidation column in the hydrogen flow and set aside. The used 401 deoxidizer will turn from green to brown. The brown layer continues to move forward along the direction of the gas flow until At the end of the deoxidation column, the deoxidizer fails. The deoxidation column that has failed can be used repeatedly after regeneration. During regeneration, hydrogen is introduced at a flow rate of not less than 60-120mL/min. The temperature is increased at a rate of 4C per minute. After maintaining the temperature at 200C and 300℃ for 1h, the temperature is increased to 450℃ and maintained at the temperature for 4h. The heating is stopped and the hydrogen is continued until it cools to room temperature before reuse.
When other deoxidizers are selected, prepare them according to their instructions. 6.3 Instrument preparation
Connect the chromatographic column prepared in 6.1 to the chromatograph. Turn on the carrier gas, and after fully replacing the air in the chromatograph system, immediately connect the deoxidation column prepared in 6.2 to the chromatograph.
Turn on the instrument according to the instrument instruction manual and adjust the operating conditions to the selected values. After the instrument is stable, use a standard mixed gas to check whether the detection capability of the instrument meets the requirements of this standard. 7 Standard mixed gas
7.1 The standard mixed gas used for the determination of fluorine, nitrogen and krypton content in oxygen must comply with the relevant national regulations on standard samples and have a certification mark and number recognized by the national standardization administrative department. 7.2 The standard mixed gas is usually a binary or multi-component mixed gas composed of fixed components argon, nitrogen and krypton and diluent oxygen. The remaining components in the multi-component mixed gas should not interfere with the determination of argon, nitrogen and krypton. 7.3 The concentration values ​​of fluorine, nitrogen and krypton in the standard mixed gas should be similar to the concentrations of argon, nitrogen and krypton in the sample to be tested, usually about 50% to 200% of the concentration of the components to be tested, or 50% to 150% of the technical indicator values ​​in the corresponding product standards. 8 Determination steps
8.1 Sampling
Safety matters in sampling should be in accordance with the provisions of GB3723. The sampling principles and general provisions of gaseous samples should comply with the provisions of GB6681. The sampling of compressed gas must use a needle valve. After the sample gas is fully replaced by the method of increasing and decreasing the pressure at least three times, the sample is directly sent to the chromatograph through the metal connecting pipe.
The sampling of liquefied gas shall comply with the provisions of Chapter 6 of GB6680. After the sample is vaporized, it is directly sent to the chromatograph through the metal connecting pipe. For sampling of gas in the pipeline, the sample should be directly sent to the chromatograph using the shortest possible metal connecting pipe. For normal pressure or negative pressure sample sampling, an aspirator is used to directly draw the sample into the chromatograph. The airtightness of the sampling gas line must be strictly guaranteed to prevent the contamination of the sample by the ambient gas. 8.2 Calibration
Send the standard mixed gas that meets the provisions of Chapter 7 of this standard into the instrument. After the sampling pipeline system is fully replaced with the standard mixed gas and a representative sample is obtained, switch the sampling valve to inject the sample into the chromatograph. Repeat the injection at least twice, and record and measure the retention time and chromatographic peak area (or peak height) of each component. When the relative average deviation of the chromatographic peak area (or peak height) measured twice does not exceed 5%, take the average value A, (or h,) as the measured value.
8.3 Determination
Put the sample according to 8.1. After the sampling pipeline system is fully replaced and a representative sample is obtained, switch the sampling valve to inject the sample into the chromatograph. Repeat the injection at least twice, and record and measure the retention time and chromatographic peak area (or peak height) of each component. When the relative average deviation of the chromatographic peak area (or peak height) of two repeated measurements does not exceed 5%, take the average value A, (or hz) as the measured value 9 Result calculation
The content of argon or nitrogen, fluorine in the sample gas is expressed by volume fraction and calculated according to the following formula: d
Where:
A (or h)
A. (or h.)
10 Report
·A or
The content of argon, nitrogen or nitrogen in the standard mixed gas, 10-6 (V/V); the content of argon, nitrogen or nitrogen in the sample gas, 10~6 (V/V); the chromatographic peak area of ​​argon, nitrogen or krypton in the standard mixed gas, mm (or peak height, mm); the chromatographic peak area of ​​argon, nitrogen or nitrogen in the sample gas, mm (or peak height, mm). The report should include the following:
All information about the sample, such as the name, number, sampling point, sampling date and time of the sample; analysis results: the concentration of argon, nitrogen or krypton expressed as volume fraction; measurement conditions and abnormal phenomena observed during the measurement and their explanations; the name of the analyst;
Analysis date;
Other operations not included in this standard and their explanations, etc. Additional notes:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. This standard was drafted by the Southwest Research Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are He Daoshan and Yu Zhongyu. 233
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