Hand-held gas chromatography-ion mobility spectrometry for on-site analysis of complex organic mixtures in air or vapors over waste sites

The strengths of Ion mobility spectrometry (IMS) are low detection limits, a wide range of application, and simplicity of design and operation. The gentle ionization processes used in IMS impart a measure of selectivity to its response. However, atmospheric pressure chemical ionization with compounds of comparable proton affinities leads to mobility spectra for which interpretive and predictive models do not exist. An alternative approach for the analysis of complex mixtures with IMS is the use of a separation device such as a gas chromatograph (GC) as an inlet. Results suggest that an IMS cell temperature of ca. 150{degrees} to 175{degrees}C provided mobility spectra with suitable spectral detail without the complications of ion-molecule clusters or fragmentation. Significant fluctuation in peak heights were observed over a 30 day test period. Neural network pattern identification techniques were applied to data obtained at room temperature and at 150{degrees}. Results showed that spectral variables within compound classes as insufficient to distinguish related compounds when mobility data was obtained using the commercial room temperature IMS cell. Similar but less severe difficulty was encountered using the 150{degrees} data. 5 refs., 3 figs., 2 tabs

Experimental ion mobility measurements in Ne-N 2

Data on ion mobility is important to improve the performance of large volume gaseous detectors, such as the ALICE TPC or in the NEXT experiment. In the present work the method, experimental setup and results for the ion mobility measurements in Ne-N(2) mixtures are presented. The results for this mixture show the presence of two peaks for different gas ratios of Ne-N(2), low reduced electric fields, E/N, 10–20 Td (2.4–4.8 kV·cm(−)(1)·bar(−)(1)), low pressures 6–8 Torr (8–10.6 mbar) and at room temperature