Simultaneous detection of benzene and toluene using a pulsed ion mobility spectrometer

Ion mobility spectrometry (IMS) is a well known method for fast trace gas detection in air. Having simple instrumentation, IMS is especially suited when portability and highest sensitivity are required. However, due to competing chemical ionization processes in the reaction region of IMS, it can be difficult or even impossible to detect small amounts of certain substances in a complex mixture. A prominent example is the detection of low benzene concentrations in the presence of higher toluene concentrations. In this paper we present experimental results of simultaneous toluene and benzene detection by using a pulsed electron source for ionization and demonstrate how this can help to overcome the major issue of atmospheric pressure chemical ionization (APCI).