Browsing by Subject "chemical warfare agents"
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Item First Supramolecular Sensors for Phosphonate Anions(2013-06) Esipenko, Nina A.; Koutnik, Petr; Minami, Tsuyoshi; Mosca, Lorenzo; Lynch, Vincent M.; Zyryanov, Grigory V.; Anzenbacher, Pavel; Lynch, Vincent M.Fluorescent tripodal anion sensors with a 1,3,5-triethylbenzene core display a turn-on fluorescence response to phosphonate and phosphate anions and may be used as optical sensors. The properties of the receptors and sensors as well as their anion binding behavior were investigated both in solution and in solid state. The turn-on fluorescence response can be leveraged in sensing of phosphate anions and, most importantly, hydrolysis products of the nerve gas sarin, isopropyl methylphosphonate (IMP), and methylphosphonate (MP). The fluorescence signal amplification in the presence of anions allows for application of these molecules in a sensor microarray suitable for high-throughput screening.Item High-sensitivity, high-selectivity detection of chemical warfare agents(American Institute of Physics, 2006-01-27) Pushkarsky, Michael B.; Webber, Michael E.; Macdonald, Tyson; Patel, C. Kumar; Webber, Michael E.We report high-sensitivity detection of chemical warfare agents nerve gases with very low probability of false positives (PFP). We demonstrate a detection threshold of 1.2 ppb 7.7 ug/m3 equivalent of Sarin with a PFP of <1:106 in the presence of many interfering gases present in an urban environment through the detection of diisopropyl methylphosphonate, an accepted relatively harmless surrogate for the nerve agents. For the current measurement time of ~ 60 s, a PFP of 1:106 corresponds to one false alarm approximately every 23 months. The demonstrated performance satisfies most current homeland and military security requirements.Item Optical detection of chemical warfare agents and toxic industrial chemicals: Simulation(American Institute of Physics, 2005-05-23) Webber, Michael E.; Pushkarsky, Michael B.; Patel, C. Kumar; Webber, Michael E.We present an analysis of optical techniques for the detection of chemical warfare agents and toxic industrial chemicals in real-world conditions. We analyze the problem of detecting a target species in the presence of a multitude of interferences that are often stochastic and we provide a broadly applicable technique for evaluating the sensitivity, probability of false positives (PFP), and probability of false negatives (PFN) for a sensor through the illustrative example of a laser photoacoustic spectrometer (L-PAS). This methodology includes (1) a model of real-world air composition, (2) an analytical model of an actual field-deployed L-PAS, (3) stochasticity in instrument response and air composition, (4) repeated detection calculations to obtain statistics and receiver operating characteristic curves, and (5) analyzing these statistics to determine the sensor’s sensitivity, PFP, and PFN. This methodology was used to analyze variations in sensor design and ambient conditions, and can be utilized as a framework for comparing different sensors.Item A Selective and Sensitive Chromogenic and Fluorogenic Detection of a Sulfur Mustard Simulant(2013-08) Kumar, Vinod; Anslyn, Eric V.; Kumar, Vinod; Anslyn, Eric V.A simple and highly selective chromogenic and fluorogenic detection of sulfur mustard (SM) simulants is reported. Dithiol 1, in the presence and absence of a mustard simulant behaves differently toward a squaraine dye (SQ), and thus provides a visual and spectroscopic signal for mustard gas. The sensor responds to the SM simulant, but not to the O-analog of mustard stimulant or nerve agent mimics and other electrophilic agents. The visual and fluorescent detection with less than 50 mu M of SM simulant shows good sensitivity. The utility of the sensor was demonstrated by analysis of SM simulant on surfaces, in soil, and in the gas phase.