DMS-IMS2, GC-DMS, DMS-MS: DMS Hybrid Devices CombiningOrthogonal Principles of Separation for Challenging Applications

摘要

Sionex Differential Mobility Spectrometer (DMS) sensors can be used as standalone detectors in many applicationsbecause of their outstanding sensitivity and selectivity. However, in applications like field screening for toxic chemicalsand explosives, the number of possible interferents may be so high that additional separation becomes useful foridentification and for quantitative measurement. For these cases, we have developed several different hybridtechnologies. (1) DMS-IMS~2integrates bipolar differential mobility ion filtration with IMS drift time measurement inIMS drift tubes, one tube for each ion polarity. (2)The Sionex GC-DMS (microAnalyzer) combines a pre-concentrator, arapid and selective GC column that operates at high temperature in an air recirculation loop, and DMS ion filtration anddetection. (3) Sionex DMS-MS interfaces have been developed for several types of mass spectrometers, and dramaticallyimprove mass spec performance by filtering out unwanted species to reduce chemical noise and improve measurementaccuracy. The Sionex DMS-IMS2 first uses DMS to select positive and negative ions based on ion mobility variation with field(the a(E) function), then uses paired IMS sections to measure the low field mobility (K(0)). DMS separation depends onmany properties including the distribution of internal charges, rigidity, and clustering. The IMS drift times depend onmolecular size and onformation at low fields. A number of applications of this technology will be described, includingCWA's, TIC/IM, and explosives.The Sionex microAnalyzer GC-DMS system combines sophisticated preconcentration, thermal desorption, GCtemperature ramping, and DMS separation and detection in a compact, portable and field-deployable package. The list ofapplications for this technology is growing rapidly, currently including CWAs, BTEX, H25 and mercaptans, and others. Sionex DMS-MS interfaces are being used to make quantitative measurements of biomarkers, including breath markers,biofluid markers, and cancer-linked agents. DMS-MS improves the performance / cost tradeoff for the massspectrometer, greatly speeds analysis compared to LC-MS, and maintains measurement accuracy.