|Abstract Title:||Coupling of Ion Mobility Spectrometry as Detector to a Micro Gas Chromatograph for Enhanced Detection Limits and Applicability|
|Session Choice:||Analytical Techniques: Chromatography and Separations|
|Presenter Name:||Mr Coen Duvekot|
|Co-authors:||Mr Daniel Sanders|
Mrs Nuria Sabugo Garcia
Mr Remko van Loon
Abstract Information :
Fast availability of results and low detection limits are key drivers for analysts nowadays. This paper shows a feasibility study for coupling ion mobility spectroscopy (IMS) as detector to a micro gas chromatograph (micro gc) to achieve both fast run times, and ppb level detection.
Micro gas chromatographs typically use a micro electromechanical (MEMS) version of a thermal conductivity detector (TCD) for compound speciation, achieving detection limit down to low ppm levels. Since most compounds have a thermal conductivity different from the GC carrier gas, the TCD responds to all these compounds and is therefore often entitled as universal detector. Quantification of compounds of interest requires separation from the matrix peak. The detection principle of Ion Mobility Spectrometry is based on the specific drift times that ions of compounds have in a defined electric field passing a drift tube with a fixed path length. Atmospheric ionization of molecules is obtained by soft chemical-ionization initiated by a tritium (3H) source with radiation below exemption limits for all EURATOM countries. For detection, the resulting ion current is measured by an electrometer as a function of time. IMS can detect gaseous compounds down to 50 - 100 ppb and below. When coupled to a micro gc, the pre separation of compounds significantly improves selectivity.
The enhanced sensitivity and selectivity by combining mirco gc with IMS allows detection of the smallest impurities of volatile compounds, even in complex mixtures. As an example the analysis of low sulfur in energy rich streams will benefit from a more sensitive and specific detector like the IMS. The advantage of using micro gc is its fast runtime, typically 30 to 90 seconds, as a result of using MEMS based injector and detector, and isothermally operated narrow bore capillary columns.