Detection organic vapors

Other materials have also been used to produce modified nanopartide films to detect organic vapors. Murray and coworkers [26] showed that the modification of nanopartides with a carboxylate ligand, which can complex with a metal ion, Cu +,... 

PPV-based block copolymers with phenylene oxide units are suitable to detect organic vapors, such as acetone, ethanol, ethyl acetate, hexane, toluene, acetic acid, methanol, and diethyl ether. The device is constructed as gold-coated copper interdigitated electrodes with a gap of 1 mm. No response is detected when the sensors are exposed to air saturated with water. Thus, hirmidity does not affect the performance. 

MacDiarmid et al. [332,333] reported the synthesis of octaani-line, an oligomer of aniline, and its use in a device to detect organic vapors such as toluene. The reversibility of the octaaniline sensor toward toluene vapors was observed to be excellent (99.7%) with a satisfactory environmental stability after a few days. 

Explosives. Explosives can be detected usiag either radiation- or vapor-based detection. The aim of both methods is to respond specifically to the properties of the energetic material that distinguish it from harmless material of similar composition. A summary of techniques used is given ia Table 7. These techniques are useful for detecting organic as well as inorganic explosives (see Explosives and propellants). 

Fixed-bed adsorbers may be operated in either intermittent or semicon-tinuous mode. A typical removal system is a semicontinuously operated dnal-bed system one bed is in adsorption mode while the other is being re generated (Fig. 13.23). " The adsorption performance of the bed can he monitored by analyzing the outlet gas. Once organic vapors are detected in the gas stream, the incoming gas stream is routed to the parallel adsorber, and the exhausted bed is regenerated. The adsorption and desorption cycles can also be fixed. 

Harden T.C. Imeson, Detection and Identification of Trace Quantities of Organic Vapors in the Atmosphere by Ion Cluster Mass Spectrometry and the Ionization Detector System ,... 

Potyrailo, R. A. Sivavec, T. M., Boosting sensitivity of organic vapor detection with silicone block polyimide polymers, Anal. Chem. 2004, 76, 7023 7027... 

Liang, C., Yuan, C.Y, Warmack, R.J., Barnes, C.E., and Dai, S., Ionic liquids A new class of sensing materials for detection of organic vapors based on the use of a quartz crystal microbalance. Anal. Chem., 74,2172-2176, 2002. 

Many of the charcoal tube methods are based on NIOSH Method P CAM 127 (4) for organic solvents. In this method, a known volume of air is drawn through a charcoal tube to trap organic vapors, the charcoal is transferred to a vial, and the sample is desorbed with carbon disulfide. The sample is analyzed by gas chromatography (GC) with flame ionization detection (FID). Most methods use CS2 as the desorption solvent because it yields good recoveries from charcoal and produces a very low flame response. 

B. M. Cordero, and M. Forina, Electronic Nose Based on Metal Oxide Semiconductor Sensors as a Fast Alternative for the Detection of Adulteration of Virgin Olive Oils, Anal. Chim. Acta 2002,459, 219 C. L. Honeyboume, Organic Vapor Sensors for Food Quality Assessment, J. Chem. Ed. 2000, 77, 338 E. Zubritsky, E-Noses Keep an Eye on the Future. Anal. Chem. 2000, 72. 

Abstract Cataluminescence (CTL) is chemiluminescence emitted in a course of catalytic oxidation. Since 1990, the present authors and coworkers have observed CTL during the catalytic oxidation of various organic vapors in air. This phenomenon has been applied to the CTL-based sensors for detecting combustible vapors. THE CTL response is fast, reproductible and proportional to the concentration of the combustible vapors of ppm orders in air. Based on two types of models of the CTL, the relationship between the CTL intensity and the rate of catalytic oxidation have been investigated analytically. In this article, the effects of catalyst temperature, gas flow-rate and gas concentration on the CTL intensity are demonstrated. Finally, various types of sensing system using the CTL-based sensor are proposed. The results of discrimination and determination of more than ten types of vapors of various concentrations are shown. 

Ambient blanks are intended to detect airborne contamination that may be affecting samples collected in atmospheres with high contents of organic vapor. This type of ambient contamination may be present at airport runways, refineries, gasoline... 

Moreover, the complex displays a completely reversible vapochromic behavior with reversible changes of color when the solid is exposed to a variety of organic vapors, which is even deeper under UV light. These results illustrate the potential applications of this complex for the detection of VOCs. 

Suspended in a sol-gel-based thin film as previously described, zeolites have been claimed to provide sensitive response to alcohols (MeOH and PrOH) while excluding other organic vapors (isooctane) solely on the basis of molecular size [132]. The excluded molecule is also highly nonpolar, in contrast to the polar alcohols that were detected the potential role of solute polarity on exclusion has... 

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