An online VOCs adsorption/thermal desorption system was developed for enhancing the sensitivity of online VOCs mass spectrometry. By integrating a fast and precise temperature control module

a large flow rate sampling strategy and a switch mode pre-concentration module

the new system can be coupled to both online VOC detection instruments and offline ones. The performance of the system

such as operating conditions

enrichment capacity

stability

was tested by using a benzene series standard gas. Meanwhile the system was used to analyze the VOCs components in indoor air. The result show that the sensitivity of the online VOCs mass spectrometry was increased by two orders of magnitude. Secondly

compared to single online VOCs mass spectrometry

the system coupled to online VOCs mass spectrometry can greatly enhance the detectability of trace amount VOCs components in indoor air. This system will provide a new technology for trace VOCs gas detection.