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Vacuum sampling device for gas chromatograph

A gas chromatograph and sampling device technology, applied in the field of vacuum sampling devices for gas chromatographs, can solve problems such as interference analysis results, detector response overload, analysis result errors, etc., to expand the response linear range and improve analysis accuracy , the effect of high analysis accuracy

Inactive Publication Date: 2017-05-24
INST OF NUCLEAR PHYSICS & CHEM CHINA ACADEMY OF
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The gas sample is injected by a commercial valve sampling system, which is easy to operate and has good quantitative repeatability, but it is not suitable for normal pressure and negative pressure sample injection analysis, and it is difficult to avoid the pollution of the gas sample by the ambient air, which will interfere with the analysis results. Especially for the quantitative analysis of trace oxygen and nitrogen components in gas samples, the oxygen and nitrogen impurities in the air will seriously interfere with the analysis results
If the traditional purging method is used to remove the air in the sampling line, it will consume a lot of time and sample gas, and it is difficult to remove the air impurities in the air.
In addition, the traditional valve injection method cannot adjust the injection pressure. When measuring high-concentration sample components or low-concentration sample components, the overload or low response of the detector will cause large errors in the analysis results.

Method used

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  • Vacuum sampling device for gas chromatograph

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Take a helium sample gas tank, install it on the position of the sample container 2, and measure the volume concentration of each impurity component in the helium sample according to the following steps.

[0028] 1a. Turn on the power switch of the housing 19, open the pressure sensor valve 11 and the vacuum gauge valve 14, and obtain the air pressure value, vacuum degree and temperature value from the pressure display instrument 9, the vacuum display instrument 16 and the temperature display instrument 7, and the temperature value is 19.9°C;

[0029] 1b. Close calibration gas valve 5, vacuum valve 17 and vent valve 13;

[0030] 1c. Start the vacuum pump 18, open the vacuum valve 17 and the sample gas valve 6 in turn, and start vacuuming;

[0031] 1d. When the reading of the vacuum display instrument 16 is lower than 5Pa, close the vacuum valve 17, open the switch of the sample container 2 until the required sample gas enters the trachea, close the switch of the sample...

Embodiment 2

[0036] Take a standard gas cylinder whose balance gas is He and whose components are 5ppmH2, 6.1ppmO2, and 7.5ppmN2, install it on the position of standard gas cylinder 1, and measure the peak area of ​​each component chromatographic peak in the standard gas according to the following steps .

[0037] 2a. Turn on the power switch of the housing 19, open the pressure sensor valve 11 and the vacuum gauge valve 14, and obtain the air pressure value, vacuum degree and temperature value from the pressure display instrument 9, the vacuum display instrument 16 and the temperature display instrument 7, and the temperature value is 19.9°C;

[0038] 2b. Close the sample gas valve 6 and the vacuum valve 17, open the switch of the standard gas cylinder 1, the standard gas valve 5 and the vent valve 13, adjust the pressure reducing valve 3, and use the standard gas to purge for 3-5 minutes;

[0039] 2c. Close the calibration gas valve 5 and the vent valve 13, start the vacuum pump 18, ope...

Embodiment 3

[0045]The implementation of this embodiment is basically the same as that of Embodiment 2, the main difference being that, considering the interference of oxygen and nitrogen in the atmosphere during the measurement process, the oxygen and nitrogen content in high-purity helium with a purity higher than 99.999% was measured. Take a high-purity helium cylinder with a purity higher than 99.999%, install it on the position of the standard gas cylinder 1, measure and analyze the oxygen and nitrogen content, and obtain the background oxygen and nitrogen volume concentration in the measurement step as O2: 0.06ppm, N2 : 0.25ppm.

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Abstract

The invention provides a vacuum sampling device for a gas chromatograph. The vacuum sampling device comprises a standard gas bottle, a sample container, the gas chromatograph and a vacuum pump, wherein the standard gas bottle and the sample container are connected with a gas inlet of the gas chromatograph through gas tubes, and the vacuum pump is connected with an exhaust port of the gas chromatograph through a gas tube. A pressure sensor for measuring a pressure value in each gas tube and a vacuum gauge for measuring the vacuum degree in each gas tube are installed on each gas tube. A temperature sensor for measuring an environment temperature value is further installed. The vacuum sampling device for the gas chromatograph improves a traditional valve sampling mode of the gas chromatograph, tested sample gas pollution caused by ambient air is avoided, and the precision of quantitative analysis on components in the sample gas such as a trace amount of oxygen and nitrogen components is effectively improved. In addition, the sampling pressure can be adjusted, the phenomenon that detector response of the gas chromatograph is overloaded or too low is avoided, a response linearity range of a detector is widened, and analytical errors are decreased.

Description

technical field [0001] The invention belongs to the technical field of gas chromatograph analyzers, in particular to a vacuum sampling device for gas chromatographs. Background technique [0002] Gas chromatography is widely used in petroleum, chemical industry, biochemistry, medicine and health, food industry, environmental protection, etc., and can perform qualitative and quantitative analysis of gases. In gas chromatography, sampling is one of the main sources of quantitative analysis errors. The principle, structure, materials used, temperature of sample injection, sample volume, speed of sample injection, tools used for sample injection, etc. will affect the quantitative and qualitative repeatability and accuracy of gas chromatographic analysis. direct impact. [0003] The gas sample is injected by a commercial valve sampling system, which is easy to operate and has good quantitative repeatability, but it is not suitable for normal pressure and negative pressure sampl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/20
CPCG01N30/20
Inventor 薛志彦兰晓华刘聪刘显坤唐彬张百甫王梓游庆明
Owner INST OF NUCLEAR PHYSICS & CHEM CHINA ACADEMY OF