title: Trace Ammonia Sensors Based on Fluorescent Near-Infrared-Emitting aza-BODIPY Dyes.
abstract: Highly sensitive ammonia sensors for environmental monitoring are presented. The sensing materials are based on fluorescent BF2-chelated tetraarylazadipyrromethene dyes (aza-BODIPYs) dyes physically entrapped in polyurethane hydrogels and dispersed in silicone rubber. This layer is covered by a hydrophobic porous Teflon membrane used as an additional proton barrier and light scattering layer. The dual-lifetime referenced (DLR) sensors make use of near-infrared (NIR)-emitting Egyptian blue as a reference material and in combination with optical fibers are read-out via a compact phase-fluorometer. The detectable concentration range can be tuned by the choice of aza-BODIPY dye or/and the hydrogel matrix. The most sensitive sensor has a limit of detection (LOD) of 0.11 μg/L and the upper detectable concentration of 300 μg/L. No cross-sensitivity toward pH is observed. The sensors show remarkable operational stability with no noticeable drift over a period of 2 weeks.
authors.affiliation: Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology , Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Strobl
authors.affiliation: Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology , Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Anna
authors.initials: A
authors.lastname: Walcher
authors.affiliation: Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology , Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Torsten
authors.initials: T
authors.lastname: Mayr
authors.affiliation: Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology , Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Ingo
authors.initials: I
authors.lastname: Klimant
authors.affiliation: Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology , Stremayrgasse 9, 8010 Graz, Austria.
authors.forename: Sergey M
authors.identifier: 0000-0001-9318-8273
authors.initials: SM
authors.lastname: Borisov