HG/T 2686-1995 Determination of trace hydrogen, oxygen, methane and carbon monoxide in inert gases Gas chromatography with zirconium oxide detector HG/T2686-1995 standard download decompression password: www.bzxz.net

Chemical Industry Standard of the People's Republic of China
Determination of trace hydrogen, oxygen, methane and carbon monoxide in inert gases Gas chromatography with zirconium oxide detector
1 Subject content and scope of application
IG/T 26B6-95
This standard specifies the determination method, instrument requirements, determination conditions, standard gas, determination steps and result processing of trace impurity components hydrogen, oxygen, xenon and carbon monoxide in inert gases.
This standard is mainly applicable to the detection of trace impurity hydrogen, oxygen, methane and carbon monoxide in gases such as ammonia, fluorine, nitrogen, argon, ammonia and xenon.
Referenced standardswwW.bzxz.Net
CB/T3723General safety rules for sampling of industrial chemical productsGB/T5274Weighing method for preparation of mixed gases for calibration of gas analysisGB/I 6680
General rules for sampling of liquefied products
GR/T 6681
General rules for sampling of gas chemical products
GR/T10627Preparation of standard mixed gases for gas analysisStatic volumetric methodGR/T10628Comparative method for determination of composition of standard mixed gases for gas analysis3 Summary of method
Aluminum oxide solid battery is used as the detector of gas chromatography. The measured components hydrogen, oxygen, methane and carbon monoxide in the sample gas are separated by the chromatographic column and enter the detector to generate corresponding chromatographic peak signals, which are then quantified by the external standard method. 4 Instrument
Use a gas chromatograph with an aluminum oxide detector: the detection limit of the instrument for hydrogen and oxygen should not be greater than 0.1×10- (V/V), and the detection limit for methane and carbon dioxide should not be greater than 0.5X10-6 (V/V). 5 Determination conditions
5.1 Carrier gas: use inert gas as carrier gas, in which the content of the component to be measured should be about one order of magnitude lower than the content of the corresponding component in the sample gas. Usually, the carrier gas is the same as the main component of the sample gas to be measured. Other gases that do not affect the measurement can also be used as carrier gas. For example: use nitrogen as carrier gas when analyzing nitrogen, and use nitrogen or chlorine as carrier gas when analyzing nitrogen and hydrogen. 5.2 The operating conditions of the instrument, such as the flow rate of the carrier gas, the operating temperature of the detector and the chromatographic column, the background voltage, etc., are all selected in accordance with the instrument instruction manual.
5.3 Chromatographic column: The chromatographic column is about 3m long, with an inner diameter of 3~4mm and a stainless steel column filled with 0.25~0,40mm 13X molecular sieve: Activate for 2~3h at a temperature of 210~240℃ and a carrier gas flow rate of 120~150ml./min. The column should be able to completely separate the components to be tested after activation.
Approved by the Ministry of Chemical Industry of the People's Republic of China on April 5, 1995 and implemented on January 1, 1996
Other equivalent methods are allowed to be used.
6 Standard gas
6.1 Bottled standard gas
HG/T 2686-95
6.1.1 Bottled standard gas should have the certification mark and number of the State Technical Supervision Bureau, or be an approved imported standard gas. 6.1.2 The base gas of the standard gas is the same as the sample gas to be tested, and the content of each component is similar to that of each component in the sample gas to be tested. It is prepared according to the provisions of GB/T5274 or GB/T10627, GB/T10628. 6.2 It is allowed to use the standard gas prepared by the exponential dilution method. When there is any objection to the analysis result, the standard gas specified in Article 6.1 should be used. 7 Determination steps
7.1 Preparation of the instrument
According to the instrument instructions, select various operating conditions and start the instrument until it enters normal working state. 7.2 Sampling
7.2.1 The safety matters of the sample towel should comply with the provisions of GB/T3723. 7.2.2 The sampling principles and general provisions of gas samples should comply with the provisions of GB/T6681. 7.2.3 The sampling of bottled gas must use a high-pressure needle valve, which is connected to the instrument sampling valve through a metal sampling tube. After replacing the residual gas in the system at least 3 times by the pressure increase and decrease method, switch the sampling valve to send the sample into the instrument. 7.2.4 The sampling of liquefied gas shall comply with the provisions of GB/6680. 7.2.5 Sampling of pipeline gas: The shortest possible metal pipeline should be used from the sampling port to the instrument. If necessary, a diffusion-proof pressure reducing valve or pressure stabilizing valve should be installed at the sampling port.
7.3 Calibration
7.3.1 Calibration with bottled standard gas: Send the standard gas that meets the provisions of Article 6.1 into the instrument through the metal sampling tube. The operation method should comply with the provisions of Article 7.2 Sampling. Measure the retention time and peak height (mm) or peak voltage (mV) of the chromatographic peak of each component. Take the arithmetic mean of at least 3 repeated calibration results as the calibration value-the relative average deviation of repeated measurements shall not be greater than 10%. 7.3.2 Calibration by exponential dilution method: follow the steps given in the instrument manual, calculate the content of each component (n×10-5V/V), and measure the chromatographic peak height (mm) or peak voltage (mV) of the corresponding component. Repeat 3 times. When the relative average deviation is not greater than 10%, take the arithmetic mean. Draw a calibration working curve of component content versus chromatographic peak height or peak voltage on double logarithmic coordinate paper. 7.3.3 Calibration cycle: When calibrating with bottled standard gas, calibrate each time the instrument is turned on or every day: When calibrating with exponential dilution method, calibrate once every half a month if the operating conditions remain unchanged. Recalibrate when the operating conditions change. 7.4 Determination
7.4.1 The sampling of sample gas shall comply with the provisions of Article 7.2. 7.4.2 Send the sample gas to the instrument under the same operating conditions as the standard gas calibration. Measure the retention time and peak voltage (mV) or peak height (mm) of each component. Take the arithmetic mean of at least 3 repeated measurement results as the measured value. The relative deviation of repeated measurements shall not be greater than 10%. B. Result processing
8.1 When using bottled standard gas for calibration, calculate the content of the component to be measured in the sample gas according to the following formula: xh
Wherein: 9,: content of component i in the sample gas, 10-6 (V/V); m——content of component i in the standard gas, 10-6 (V/V); ,—peak height value of component i in the sample gas·mm; h——peak height value of component i in the standard gas, mm, 8.2 When using the exponential dilution method for calibration, according to the peak voltage or peak height measurement values ​​of each component in the sample gas, find the corresponding 3
content on the standard T curve and it shall be the measurement result.
The report should include the following contents:
HG/T 2686—95
Sample name, number and other information about the sample; h.
Analysis date;
Instrument and operating conditions;
Calibration method, standard sample and necessary instructions: abnormal phenomena observed during measurement and their explanation; analysis results, content of each component in the sample gas (expressed as volume fraction); name of the analyst, etc.
Additional instructions:
This standard was proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China, and this standard is technically managed by the Southwest Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Shanghai Chemical Research Institute of the Ministry of Chemical Industry. The main drafter of this standard is Lin Youshun.
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