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A high-speed, high-performance, microfabricated comprehensive two-dimensional gas chromatograph

Lab on a Chip

Whiting, Joshua J.; Myers, Edward; Manginell, Ronald P.; Moorman, Matthew W.; Anderson, John M.; Fix, Cory S.; Washburn, Cody M.; Staton, Al; Porter, Daniel; Graf, Darin; Wheeler, David R.; Howell, Stephen; Richards, John R.; Monteith, Haley; Achyuthan, Komandoor A.; Roukes, Michael; Simonson, Robert J.

A small, consumable-free, low-power, ultra-high-speed comprehensive GC×GC system consisting of microfabricated columns, nanoelectromechanical system (NEMS) cantilever resonators for detection, and a valve-based stop-flow modulator is demonstrated. The separation of a highly polar 29-component mixture covering a boiling point range of 46 to 253 °C on a pair of microfabricated columns using a Staiger valve manifold in less than 7 seconds, and just over 4 seconds after the ensemble holdup time is demonstrated with a downstream FID. The analysis time of the second dimension was 160 ms, and peak widths in the second dimension range from 10-60 ms. A peak capacity of just over 300 was calculated for a separation of just over 6 s. Data from a continuous operation testing over 40 days and 20000 runs of the GC×GC columns with the NEMS resonators using a 4-component test set is presented. The GC×GC-NEMS resonator system generated second-dimension peak widths as narrow as 8 ms with no discernable peak distortion due to under-sampling from the detector.

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μchemLab: Twenty years of developing CBRNE detection systems with low false alarm rates

Proceedings of SPIE - The International Society for Optical Engineering

Whiting, Joshua J.; Myers, Edward B.; Manginell, Ronald P.; Moorman, Matthew W.; Pfeifer, Kent B.; Anderson, John M.; Fix, Cory S.; Washburn, Cody M.; Staton, Alan; Porter, Daniel; Graf, Darin; Wheeler, David R.; Richards, John R.; Achyuthan, Komandoor A.; Roukes, Michael; Simonson, Robert J.

Gas Chromatography (GC) is routinely used in the laboratory to temporally separate chemical mixtures into their constituent components for improved chemical identification. This paper will provide a overview of more than twenty years of development of one-dimensional field-portable micro GC systems, highlighting key experimental results that illustrate how a reduction in false alarm rate (FAR) is achieved in real-world environments. Significantly, we will also present recent results on a micro two-dimensional GC (micro GCxGC) technology. This ultra-small system consists of microfabricated columns, NanoElectroMechanical System (NEMS) cantilever resonators for detection, and a valve-based stop-flow modulator. The separation of a 29-component polar mixture in less than 7 seconds is demonstrated along with peak widths in the second dimension ranging from 10-60 ms. For this system, a peak capacity of just over 300 was calculated for separation in about 6 s. This work has important implications for field detection, to drastically reduce FAR and significantly improve chemical selectivity and identification. This separation performance was demonstrated with the NEMS resonator and bench scale FID. But other detectors, suitably fast and sensitive can work as well. Recent research has shown that the identification power of GCxGC-FID can match that of GC-MS. This result indicates a path to improved size, weight, power, and performance in micro GCxGC systems outfitted with relatively non-specific, lightweight detectors. We will briefly discuss the performance of possible options, such as the pulsed discharge helium ionization detector (PDHID) and miniature correlation ion mobility spectrometer (mini-CIMS).

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Characterization of chemical contaminants and their spectral properties from an atmospheric pressure ns-pulsed microdischarge in neon

Physics of Plasmas

Sillerud, Colin H.; Schwindt, Peter S.; Moorman, Matthew W.; Yee, B.T.; Anderson, John M.; Pfeifer, Nathaniel B.; Hedberg, E.L.; Manginell, Ronald P.

Portable applications of microdischarges, such as the remediation of gaseous wastes or the destruction of volatile organic compounds, will mandate operation in the presence of contaminant species. This paper examines the temporal evolution of microdischarge optical and ultraviolet emissions during pulsed operation by experimental methods. By varying the pulse length of a microdischarge initiated in a 4-hole silicon microcavity array operating in a 655 Torr ambient primarily composed of Ne, we were able to measure the emission growth rates for different contaminant species native to the discharge environment as a function of pulse length. It was found that emission from hydrogen and oxygen impurities demonstrated similar rates of change, while emissions from molecular and atomic nitrogen, measured at 337.1 and 120 nm, respectively, exhibited the lowest rate of change. We conclude that it is likely that O2 undergoes the same resonant energy transfer process between rare gas excimers that has been shown for H2. Further, efficient resonant processes were found to be favored during ignition and extinction phases of the pulse, while emission at the 337.1 nm line from N2 was favored during the intermediate stage of the plasma. In addition to the experimental results, a zero-dimensional analysis is also presented to further understand the nature of the microdischarge.

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Fundamental Scaling of Microplasmas and Tunable UV Light Generation

Manginell, Ronald P.; Sillerud, Colin H.; Hopkins, Matthew M.; Yee, Benjamin T.; Moorman, Matthew W.; Schwindt, Peter S.; Anderson, John M.; Pfeifer, Nathaniel B.

The temporal evolution of spectral lines from microplasma devices (MD) was studied, including impurity transitions. Long-wavelength emission diminishes more rapidly than deep UV with decreasing pulse width and RF operation. Thus, switching from DC to short pulsed or RF operation, UV emissions can be suppressed, allowing for real-time tuning of the ionization energy of a microplasma photo-ionization source, which is useful for chemical and atomic physics. Scaling allows MD to operate near atmospheric pressure where excimer states are efficiently created and emit down to 65 nm; laser emissions fall off below 200 nm, making MD light sources attractive for deep UV use. A first fully-kinetic three-dimensional model was developed that explicitly calculates electron-energy distribution function. This, and non-continuum effects, were studied with the model and how they are impacted by geometry and transient or DC operation. Finally, a global non-dimensional model was developed to help explain general trends MD physics.

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Genomics-enabled sensor platform for rapid detection of viruses related to disease outbreak

Brozik, Susan M.; Polsky, Ronen P.; Campbell, DeAnna M.; Manginell, Ronald P.; Moorman, Matthew W.; Edwards, Thayne L.; Anderson, John M.; Pfeifer, Kent B.; Branch, Darren W.

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19 Results
19 Results