Sionex Differential Mobility Spectrometer (DMS) sensors can be used as standalone detectors in many applications because of their outstanding sensitivity and selectivity. However, in applications like field screening for toxic chemicals and explosives, the number of possible interferents may be so high that additional separation becomes useful for identification and for quantitative measurement. For these cases, we have developed several different hybrid technologies. (1) DMS-IMS 2 integrates bipolar differential mobility ion filtration with IMS drift time measurement in IMS drift tubes, one tube for each ion polarity. (2)The Sionex GC-DMS (microAnalyzer) combines a pre-concentrator, a rapid and selective GC column that operates at high temperature in an air recirculation loop, and DMS ion filtration and detection.(3) Sionex DMS-MS interfaces have been developed for several types of mass spectrometers, and dramatically improve mass spec performance by filtering out unwanted species to reduce chemical noise and improve measurement accuracy.The Sionex DMS-IMS 2 first uses DMS to select positive and negative ions based on ion mobility variation with field (the α(E) function), then uses paired IMS sections to measure the low field mobility (K(0)). DMS separation depends on many properties including the distribution of internal charges, rigidity, and clustering. The IMS drift times depend on molecular size and conformation at low fields. A number of applications of this technology will be described, including CWA's, TIC/TIM, and explosives.The Sionex microAnalyzer GC-DMS system combines sophisticated preconcentration, thermal desorption, GC temperature ramping, and DMS separation and detection in a compact, portable and field-deployable package. The list of applications for this technology is growing rapidly, currently including CWAs, BTEX, H 2 S 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 mass spectrometer, greatly speeds analysis compared to LC-MS, and maintains measurement accuracy. Differential mobility spectrometry 1,2,3 (DMS) is recognized as a powerful tool for separation and characterization of gasphase ions. In DMS, ions are distinguished by the difference between mobilities at high and low electric fields, exploiting the fact that ion mobility values depend on the applied field strength. Developed and refined over the past decade, differential mobility spectrometry (DMS) is also known as field-asymmetric waveform ion mobility spectrometry (FAIMS) 4 (FAIMS is often used to refer to a coaxial configuration). Several configurations of DMS analyzers have shown response to trace amounts of chemical species including explosives 5,6 , chemical warfare agents and simulants 7 , volatile organic compounds 8 , and a variety of other organic and inorganic substances 9 . Hybrid DMS techniques such as GC-DMS 10 , DMS-IMS 11 , D...

Microplastics (MPs) have been found in aqueous environments ranging from rural ponds and lakes to the deep ocean. Despite the ubiquity of MPs, our ability to characterize MPs in the environment is limited by the lack of technologies for rapidly and accurately identifying and quantifying MPs. Although standards exist for MP sample collection and preparation, methods of MP analysis vary considerably and produce data with a broad range of data content and quality. The need for extensive analysis-specific sample preparation in current technology approaches has hindered the emergence of a single technique which can operate on aqueous samples in the field, rather than on dried laboratory preparations. In this perspective, we consider MP measurement technologies with a focus on both their eventual field-deployability and their respective data products (e.g., MP particle count, size, and/or polymer type). We present preliminary demonstrations of several prospective MP measurement techniques, with an eye towards developing a solution or solutions that can transition from the laboratory to the field. Specifically, experimental results are presented from multiple prototype systems that measure various physical properties of MPs: pyrolysis-differential mobility spectroscopy, short-wave infrared imaging, aqueous Nile Red labeling and counting, acoustophoresis, ultrasound, impedance spectroscopy, and dielectrophoresis.

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