Abstract:
When analyzing volatile organic compounds (VOCs) in the air, the pre-treatment method of Tenax TA tube adsorption-secondary thermal desorption has disadvantages such as long aging time of Tenax TA tube and adsorption performance decreasing with increasing cycle adsorption times. The pre-treatment method of activated carbon tube adsorption-solvent desorption has disadvantages such as high toxicity of carbon disulfide. Therefore, the study mentioned by the title was conducted. The sampling tube was filled with silanized glass wool, 200 mg of activated carbon, silanized glass wool, and inert metal filter in sequence to prepare the activated carbon sampling tube. A mixture of 22 VOCs standard solutions was injected into the self-made aged activated carbon sampling tube to prepare standard sampling tube series, which were connected with a secondary thermal desorption instrument for determination by gas chromatography-mass spectrometry. It was shown that the self-made activated carbon sampling tube had a strong adsorption preference for VOCs with a carbon atom number of no more than 7. The response of impurities in aged activated carbon sampling tube was weak, which did not interfere with the determination of 22 target VOCs. At the same time, activated carbon was inexpensive and easy to obtain, making it suitable as a disposable filler to meet the needs of immediate testing. Linear relationships of the mass and peak area of 22 VOCs were kept in definite ranges, with detection limits (3S/N) in the range of 0.03‒0.22 ng. The activated carbon standard sampling tubes containing 150, 450 ng of VOCs were repeatedly analyzed 6 times, giving recoveries in the range of 86.1%‒103% and 97.7%‒107%, and RSDs (
n=6) of the determined values of target VOCs in the range of 0.74%‒4.5% and 0.42%‒4.7%, respectively.