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The electrospinning technique has allowed that very different materials are deposited as sensitive layers on Love-wave devices forming a low cost and successful sensor array. Their excellent sensitivity, good linearity and short response time are reported in this paper. Several materials have been used to produce the nanofibers: polymers as Polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP) and Polystirene (PS); composites with polymers as PVA+SnCl4; combined polymers as PS+Poly(styrene-alt-maleic anhydride) (PS+PSMA) and metal oxides (SnO2). In order to test the array, well-known chemical warfare agent simulants (CWAs) have been chosen among the volatile organic compounds due to their importance in the security field. Very low concentrations of these compounds have been detected by the array, such as 0.2 ppm of DMMP, a simulant of sarin nerve gas, and 1 ppm of DPGME, a simulant of nitrogen mustard. Additionally, the CWA simulants used in the experiment have been discriminated and classified using pattern recognition techniques, such as principal component analysis and artificial neural networks., (Copyright © 2013 Elsevier B.V. All rights reserved.)

An array of Love-wave sensors based on quartz and Novolac has been developed to detect chemical warfare agents (CWAs). These weapons are a risk for human health due to their efficiency and high lethality; therefore an early and clear detection is of enormous importance for the people safety. Love-wave devices realized on quartz as piezoelectric substrate and Novolac as guiding layer have been used to make up an array of six sensors, which have been coated with specific polymers by spin coating. The CWAs are very dangerous and for safety reasons their well known simulants have been used: dimethylmethyl phosphonate (DMMP), dipropyleneglycol methyl ether (DPGME), dimethylmethyl acetamide (DMA), dichloroethane (DCE), dichloromethane (DCM) and dichloropentane (DCP). The array has been exposed to these CWA simulants detecting very low concentrations, such as 25 ppb of DMMP, a simulant of nerve agent sarin. Finally, principal component analysis (PCA) as data pre-processing and discrimination technique, and probabilistic neural networks (PNN) as patterns classification technique have been applied. The performance of the sensor array has shown stability, accuracy, high sensitivity and good selectivity to these simulants., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Abstract: An array made up of Love wave sensors based on quartz/SiO2 is proposed as a detection system for chemical warfare agents (CWA). The array is composed of one reference and six devices coated with different polymers means of spray coating technique. The system has been tested with well-known CWA simulants: dimethylmethyl phosphonate (DMMP), dipropyleneglycol methyl ether (DPGME), dimethylmethyl acetamide (DMA), dichloroethane (DCE), dichloromethane (DCM), and dichloropentane (DCP), detecting very low concentrations, such as 40ppb of DMMP, a simulant of sarin nerve gas. Additionally, principal component analysis (PCA) as a data pre-processing and discrimination technique, and probabilistic neural networks (PNN) as a pattern classification technique, have been applied, obtaining a clear discrimination and a correct classification. [Copyright &y& Elsevier]

Abstract: An E-nose based on surface acoustic wave (SAW) sensors has been developed, and sensitive polymer coatings have been optimized to detect simulants of chemical warfare agents (CWAs). The polymers selected have allowed to discriminate among simulants and classify them at low concentrations in air through Pattern Recognition Methods. Good detection responses have been achieved for very low concentrations, such as 0.05ppm for Dimethyl methylphosphonate (DMMP) and 0.5ppm for dipropylene glycol monomethyl ether (DPGME). [Copyright &y& Elsevier]