In this study a hand-held ion mobility spectrometer was used to characterize the vapors produced by alpha-chloroacetophenone (CN) and 2-chlorobenzylidenemalononitrile (CS), their isomers, and their degradation products at ambient temperature and 50 C, and in both the positive- and negative-ion acquisition modes. Minimum determinable residues were as follows: in the negative-ion acquisition mode at ambient temperature, CN 0.5 mu g, CS 10 mg; at 50 C, CN 0.5 mu g, CS 16 mu g; and in the positive-ion acquisition mode at ambient temperature, CN 0.5 mu g, CS not detected; at 50 C, CN 0.1 mu g, CS not detected. The steady-state reproducibility was found to be independent of ion acquisition mode but dependent on signal intensity and background noise [relative standard deviation (RSD) 3-17%]-the smaller the signal, the greater the variation. The dayto-day variation in positive- and negative-mode signal intensities showed the same trends (RSD 3-33%). By comparing positive-and negative-ion mode spectra, it was possible to differentiate not only between CN and CS but also between their isomers and breakdown products.
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.
Contact your librarian or system administrator
Login to access OSA Member Subscription