Volatile toxic compound detection by surface acoustic wave sensor array coated with chemoselective polymers deposited by laser induced forward transfer: Application to sarin

In this paper we present a sensor array based on surface acoustic wave (SAW) resonators coated with three chemoselective polymers: polyepichlorhydrine (PECH), polyisobutylene (PIB), and polyethylenimine (PEI), deposited by laser-induced forward transfer (LIFT) using a XeCl laser. The targets for the LIFT process were prepared by matrix assisted pulsed laser evaporation (MAPLE). The sensor array was tested upon exposure to dimethyl methylphosphonate (DMMP, a simulant for nerve gases and pesticides containing phosphonate ester groups), dichloromethane (DCM, an industrial applied toxic compound and simulant for choking agents, such as chlorine or phosgene), and ethyl acetate (EtOAc, a wide spread solvent in medical and industrial applications which can be harmful to humans) vapors, and sarin (GB) gas, showing, for each of the sensors, a different sensitivity to the selected chemical agents. The best sensitivities for DMMP and DCM, obtained by using a PECH coated sensor, are 66.23 Hz/ppm and 0.034 Hz/ppm, respectively, whereas the best sensitivity for EtOAc, obtained using PIB, is 0.33 Hz/ppm. A very low concentration (1.8 ppm) of GB was detected within a time to reach the saturation less than 1 min. The measured concentration is below the median lethal dose inhaled (11.3–16.2 ppm min) [1]. A detection limit of 9.24 ppb was calculated for PECH coated sensor exposed to GB.