Mutual influences of halogenated compounds during atmospheric pressure chemical ionization

Sensor techniques and especially ion mobility spectrometry (IMS) play an ever growing role in environmental monitoring. Due to the sensitive detection of halogenated compounds IMS is predestinated for this application field. However, there are many influencing factors which can affect the signal response of a certain compound, i. e. temperature, humidity and cross sensitivity. In this study we investigate the mutual influence of halogenated hexanes (C6H13X) regarding to their simultaneous detectability and signal response in ion mobility spectra. It is known from literature that the atmospheric pressure chemical ionization of halogenated compounds precedes through dissociative electron transfer. In the negative measurement mode product ions in the form of (H2O)(n)X-can be detected. We quantified the decrease of signal response of the measured halogenated target compounds in dependency of the concentration of the affecting substance provided. We observed that the influence on the signal intensity of halogenated substances increases in the following order of halogenated admixtures: F < Cl < Br < I. Furthermore it is shown that the temperature of the drift cell can be used to influence the extent of cross sensitivity.