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Leaflet GC-IMS Library Search - 2 Pages

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Catalogue excerpts

GCxIMS Library Search Compound Identification Software for Gas Chromatograph-Ion Mobility Spectrometer The new software GCxIMS Library Search makes identification and characterization of volatile organic compounds (VOC’s) easy and fast. Using both, a Gas-Chromatographic and Ion Mobility based separation leads in 2dimensional data of the sample; in combination with a high sensitive detection via Ion-MobilitySpectrometry at the same time (Fig. 1). Identification of compounds is supported by matching both (GC & IMS) compound-specific separation properties. The gaschromatographic retention times can be normalized to retention indices (RI) [1], that can be matched to literature- and database- values (Fig.2). Fig.1: 3-dimensional representation of a GC-IMS measurement. The separating effect of both techniques, GC & IMS, can be clearly seen. A signal is defined by one or more vector pairs (Dt, RI), which is unique for a defined substance. Implemented NIST2014 RI DATABASE (non-restricted) The NIST GC Method and Retention Index Database provides retention index data and gas chromatographic conditions for ~83.000 compounds on polar and non-polar stationary phase used with packed and open tubular columns. The software comes with a full nonrestricted version of the NIST2014 Retention Index Database including NIST search software. The database includes ~400.000 annotated Kovats/Lee retention indices and ~83.000 compounds. The ion mobility drift time (Dt) is also a specific parameter for a compound at constant measurement conditions. The measurement condition- based shift can be overcome by normalization of Dt values when related to the reactant ion peak (RIP), which is directly accessible in IMS spectra in positive polarization (Fig.3). [1] Kováts, E. Helv. Chim. Acta, 1958, 41 (7): 1915–32, doi:10.1002/hlca.19580410703 Fig.2: Substance retention times (Rt) strongly depend on system parameters, such as temperature or the chemical properties of the used GC column, e.g. Therefore the retention time is converted into a systemindependent constant, the Kovats retention index, based on a series of adjacently eluting alkanes and there arbitrarily assigned RI value

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Click Position Rl R1 Dt 1095.5    111.984    1.8837 [+]GAS__. Bypass Filter List of matching retention indices Confined list of matching GC retention indices in combination with matching IMS drift times Results generated by using different GC columns Fig-3 : Screenshot of an examplary signal identification. After selecting the signal of interest the identification routine of the software starts searching for matches of retention times and IMS drift times in the NIST & GAS databases. The search for identification of unknown compounds is initiated by clicking on the respective signal peak in the...

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