Photoionization gas chromatography detection method of organic volatile compounds in air

An organic volatile matter and gas chromatography technology, which is applied in the field of photoionization gas chromatography detection of organic volatile matter in the air, can solve the problems of increasing sample adsorption, desorption process, longer detection period, and low desorption recovery rate, etc. Achieve the effect of high sensitivity, improved test accuracy and high detection

Inactive Publication Date: 2009-09-23
KUNMING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This not only increases the adsorption and desorption process of the sample, but also makes the detection cycle longer, and more importantly, introduces new systematic errors and random errors in the sample processing, as well as the problem of low desorption recovery rate.

Method used

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  • Photoionization gas chromatography detection method of organic volatile compounds in air
  • Photoionization gas chromatography detection method of organic volatile compounds in air
  • Photoionization gas chromatography detection method of organic volatile compounds in air

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Determination of the concentration of benzene, toluene and xylene in the laboratory.

[0043] The detection system includes: comprehensive syringe container, chromatograph, analyzer.

[0044] Detection steps:

[0045] 1. Sampling: Use a gas sampling syringe to collect 1L (volume under standard conditions) of air on site, and seal the air inlet;

[0046] 2. Determination of the calibration factor: take 0.5 mg of n-hexane, benzene, toluene, and xylene standard liquids and add them to a sampling bag filled with 1L of high-purity nitrogen to prepare a reserve gas. Dilute the reserve gas 1000 times with high-purity nitrogen in another gas distribution syringe, and configure it as an internal standard gas with a concentration of 0.5mg / 1000L of n-hexane, benzene, toluene, and xylene; turn on the power of the chromatograph, and pre- After heating for 30 minutes, adjust the working temperature to 50°C and the pressure to 6pa; adjust the carrier gas flow rate to 15mL / min, direc...

Embodiment 2

[0053] Concentration determination of VOCs in the office.

[0054] The detection system includes: comprehensive syringe container, chromatograph, analyzer.

[0055]Detection steps:

[0056] 1. Sampling: Use a gas sampling syringe to collect 1L (volume under standard conditions) of air on site, and seal the air inlet.

[0057] 2. Draw a standard curve: prepare a VOCs stock solution with a concentration of 1 μL / mL in a 5 mL volumetric flask with methanol as the diluent. Then use a 100mL syringe to dilute and vaporize the stock solution respectively to make the concentration C 1 =0.10mg / m 3 、C 2 =0.20mg / m 3 、C 3 =0.30mg / m 3 、C 4 =0.40mg / m 3 VOCs standard gas. Turn on the power of the chromatograph, preheat for 30 minutes, adjust the working temperature to 50°C, and the pressure to 6pa; adjust the flow rate of the carrier gas to 15mL / min, inject 10.0mL of standard gas directly, and start the instrument. From figure 2 The retention time and peak area of ​​each componen...

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Abstract

The invention relates to a photoionization (PID) gas chromatography detection method of organic volatile compounds in the air. The n-hexane internal standard method or the standard gas external standard method is used for detection. The detection method is characterized by fast response speed, high sensitivity and low detection limit (not more than 10ppb); the detection method can use a sampler for collecting gas and then directly inject a sample to a chromatograph for test and can also bring the chromatograph to the test site and complete the sampling from the environmental air, the sample injection and the test at one time. The detection method does not need to use a solid sorbent for concentration and does not need to carry out desorption by thermal desorption. Therefore, the detection method simplifies the detection procedure, reduces the system error and the random error caused during the absorption, the desorption and the extraction processes, greatly shortens the detection cycle and leads the detection result to be more accurate.

Description

technical field [0001] The invention relates to the technical field of organic gas detection, in particular to a photoionization gas chromatography detection method for volatile organic compounds (VOCs) in the air. Background technique [0002] Gas chromatography (Gas Chromatography, GC) uses the different distribution coefficients, adsorption coefficients or permeability of substances in solid-gas two-phase to realize analysis and detection. Ordinary flame ionization (FID) gas chromatography requires hydrogen as the combustion gas during detection, so a temperature control box is required to accurately control the temperature, heating rate, and temperature and heating rate during analysis. The entire detection system is relatively complicated and bulky, and can only be used in laboratories. In addition, due to the performance limitation of the (FID) detector, the detection speed, sensitivity and detection accuracy are all restricted. For the detection of harmful gases in ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/72
Inventor 钱天才周烈兴王绍华牟雷王军丽
Owner KUNMING UNIV OF SCI & TECH
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