Preface
Researchers studying indoor air quality typically refer to all indoor organic gaseous substances they sample and analyze as TVOC (Total Volatile Organic Compounds). TVOC has an irritating odor, and some of its constituent compounds are genotoxic. Exposure to TVOC may cause adverse reactions such as disruptions to the body’s immune system. Therefore, the quantitative monitoring index of TVOC in the air must be controlled within the strict limits specified by national regulations.
- Abstract
A certain volume of air sample is collected using a Tenax-TA adsorption tube, where volatile organic compounds (VOCs) in the air are retained. The adsorbed VOCs are desorbed by heating the adsorption tube with a thermal desorption device, and the desorbed gas is injected into a gas chromatograph for chromatographic analysis. Qualitative identification is performed based on retention time, and quantitative determination is conducted using peak area.
- Detection Index
TVOC (Total Volatile Organic Compounds)
III. Instrument Configuration
- Thermal Desorption Device: Temperature-controllable, adjustable gas flow rate, equipped with a six-way valve and a sample loop.
- Gas Chromatograph (Model: GC5890N): Equipped with a Flame Ionization Detector (FID) for high sensitivity.
- Dedicated Capillary Chromatographic Column: Weak polarity, 50m × 0.32mm × 1.0μm.
- Standard Samples: Standard solutions of benzene, toluene, p-(m-)xylene, o-xylene, styrene, ethylbenzene, butyl acetate, and undecane.
- Two-Channel Air Sampler: Stable flow rate during sampling, with a flow range covering 0.5 L/min.
- Sampling Adsorption Tube: Glass tube or smooth inner-wall stainless steel tube filled with 200mg of Tenax-TA adsorbent (particle size: 0.18mm~0.25mm, 60~80 mesh). Before use, the tube must be activated by heating with nitrogen; the activation temperature should be higher than the desorption temperature, and the activation time should be no less than 30 minutes until no impurity peaks are detected. Desorption temperature: 280℃.
- Two-Channel Chromatographic Workstation: One workstation can connect to two chromatographs.
- Gas Sources: Nitrogen cylinder, hydrogen generator, air generator.
- Experimental Conditions
- Column Temperature: Initial temperature 50℃ (held for 5 minutes), heating rate 6℃/min, final temperature 250℃ (held for 5 minutes).
- Carrier Gas: Nitrogen; column front pressure 0.06MPa; split injection mode.
- Vaporization Temperature: 220℃; Detector (FID) Temperature: 250℃.
- Chromatogram
(Chromatogram to be attached)
- Reference Materials
- GB 50325-2011 (National Standard of the People’s Republic of China)
- ISO 16000:2004
- ISO 16017-1:2000
VII. Main Instrument Configuration
- GC5890N Gas Chromatograph (equipped with FID, packed column injection system, program temperature control, and rear door opening function)
- KJA-3L/5L Air Generator, KJA-300/500 Hydrogen Generator
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