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Method for analyzing Freon 12 concentration

A freon and concentration technology, applied in analytical materials, material separation, measurement devices, etc., can solve the problems of unseen molecular sieve packed columns and electron capture detectors for CFC12 detection, and achieve the effect of reducing analysis costs and improving analysis efficiency.

Inactive Publication Date: 2008-12-17
KUNMING UNIV OF SCI & TECH
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In gas chromatography analysis, capillary columns and Porasil (porous silica gel) packed columns are often used in chromatographic columns, but molecular sieve packed columns and electron capture detectors (ECD) are not used to detect CFC12.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The pressure drop is 3MPa, reducing the oxygen content to less than one part per million.

[0024] 2. Chromatographic column aging: fill 5A molecular sieve into In the stainless steel chromatographic column, the gas inlet temperature of the chromatograph is 100°C, the column oven temperature is 200°C, and the detector temperature is 350°C. A needle valve is used to input the carrier gas flow rate at 15mL / min, and the aging time is 5h.

[0025] 3. Gas preparation with known CFC12 concentration: inject 1mL of CFC12 gas into a 100mL syringe with a syringe, dilute to 100mL with air, shake the syringe to mix the gas evenly, and obtain a concentration of 10000mL / m 3 standard sample. Use similar methods to prepare sequentially until the concentration is 100mL / m 3 , 50mL / m 3 , 10mL / m 3 , 5mL / m 3 , 1mL / m 3 , 0.5mL / m 3 , 0.1mL / m 3 , 0.05mL / m 3 , 0.01mL / m 3 , 0.005mL / m 3 10 concentrations of standard samples.

[0026] 4. Chromatographic conditions: the temperature of...

Embodiment 2

[0031] Take 1mL of CFC12 standard samples respectively, inject them into the chromatograph together with the carrier gas from the injection port, measure the peak area of ​​the standard samples, and calculate the peak area value. Calculate the slope and the intercept of the standard curve according to the method of least squares, take the peak area as the independent variable, and the concentration as the dependent variable, and obtain the linear regression equation of the standard curve as

[0032] c=-0.1529+2.2916×10 -5 S (2)

[0033] The peak area is 68427Hz·s. The CFC12 concentration in the sample to be tested calculated by formula (2) is 14.14mL / m 3 .

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PUM

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Abstract

The invention relates to a method for analyzing freon-12 by utilizing a gas chromatograph, and belongs to the technology field of gas analytical detection. The method comprises the following steps: injecting a CFC12 sample to be measured into the gas chromatograph, and separating the CFC12 sample from other substances in a 5A molecular sieve chromatography column and measuring the concentration of the separated CFC12 sample via an electron capture detector. The method adopts the retention time of the chromatogram peak to qualify and adopts the peak height or the peak area of the chromatogram peak to quantify. The response time of the method is only 1min, thereby improving the analytical efficiency. The expensive automatic sampling device is avoided by adopting a manner of manual sampling, thereby reducing the analytical cost. CFC12 in the range of 100-0.001mL / m<3> can be measured by the molecular sieve packed column.

Description

1. Technical field [0001] The invention relates to a method for analyzing Freon-12 by a gas chromatograph, belonging to the technical field of gas analysis and detection. 2. Background technology [0002] Freon 12 (CFC12) is a compound that does not exist in nature. Since it was put into production in the 1930s, it has been widely used as refrigerant, solvent, cleaning agent and aerosol propellant, etc. After they are discharged into the atmosphere, they are quite stable and hardly degrade in the troposphere, so that their concentration in the troposphere atmosphere rises sharply. CFC12 is a chemically inert gas in the tropospheric atmosphere, but in the stratosphere it is -9 ~220×10 -9 m ultraviolet light irradiation, photolysis releases chlorine atoms, reacts with ozone to generate ClO molecules, and cyclically catalyzes the loss of ozone. In addition, due to the strong absorption of infrared rays by the C-X bond in the molecule, CFC12 is also a strong greenhouse gas. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/86G01N30/02
Inventor 张朝能宁平马彩霞黄瑞华
Owner KUNMING UNIV OF SCI & TECH
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