Rapid Detection of Trace Volatile Organic Compounds By Electric Driven Cryo-Trap Movable Mass Spectrometer

An electric driven cryo-trap enrichment apparatus for the movable mass spectrometer was designed to realize rapid and automatic detection of trace volatile organic compounds (VOCs) in the atmosphere. Compared with traditional cryo-trap with refrigerant, the lowest temperature of cryocooler was down to -196 degrees C and it was easy to carry due to its small size, light weight and refrigerant-free. Cryo-trap combined with time-of-flight mass spectrometer was used to analyze benzene, toluene and xylene, and the result showed that the signal strength of benzene, toluene and xylene, with the cryo-trap enrichment, was improved by 212-fold, 254-fold and 242-fold, and the recoveries reached 98%, 87% and 87%, respectively. The analytical time for single sample was only 14 min. The electric driven cryo-trap combined with on-line mass spectrometer was used to detect 39 kinds of VOCs listed in TO-14 method of EPA and ambient air, and the sensitivity of the newly designed instrument was better than the threshold of national indoor VOCs. The combination of electric driven cryo-trap and time-of-flight mass spectrometer could be used for rapid enrichment and monitoring of trace VOCs in the atmosphere and indoor air, showing great potential in in-site measurement and real-time monitoring of volatile organic pollutants.