Sol-gel based mid-infrared e vanescent wave sensors for detection of organophosphate pesticides in aqueous solution

摘要

This work demonstrates the application of organically modified sol-gels as recognition layers combined with mid-infrared evanescent wave sensors for in situ detecton of nitratedorganics in aqueous media.Sol-els were preparedby acid-catalyzed copolymerization of phenyltrimethoxysilane (PTMOS)ad tetramethoxysilane (TMOS)and were spin-coated onto znSe attenuated total reflection (ATR)waveguides.These sneosrs wereinvestigated with respect to tier enrichment properties of selected organophosphates,i.e.parathion,fenitrothion adn paraoxon,respectively,and their capability of suppressing interfering water background absorptions.Figures of merit are derived fro calibration curves determined to assess sensitivity ad reproducibility of the applied sensor system.It can be concudedthat sol-gel coated infrared optical sensors enable reproducible detection of organophosphates down to the sub-pp concentration rane.Furhtermore,measurement of spiked river water samples demonstrates feasibility as remote field sensors system.Once the required sensitivity is achieved,sol-gel based mid-infrared enanescent wave sensors have the potential of being an alternative to commonly applied biosensors for detection of organophosphtes in environmental analysis,since they provide superior mechanical and chemical stability during application relevant periods of time.