title: iCONVERT: an integrated device for the UV-assisted determination of H2S via mid-infrared gas sensors.
abstract: In this technical note, we describe an integrated device platform for performing in-flow gaseous conversion reactions based on ultraviolet (UV) irradiation. The system combines, using the same footprint, an integrated UV-conversion device (iCONVERT), a preconcentrator unit (iPRECON), and a new generation of mid-infrared (MIR) gas cell simultaneously serving as a photon conduit, i.e., so-called substrate-integrated hollow waveguide (iHWG) optically coupled to a compact Fourier transform-infrared (FT-IR) spectrometer. The iCONVERT is assembled from two blocks of aluminum (dimensions, 75 mm × 50 mm × 40 mm; L × W × D) containing 4 miniaturized UV-lamps (47mm × 6 mm × 47 mm each). For the present study, the iPRECON-iCONVERT-iHWG sensing platform has specifically been tailored to the determination of H2S in gaseous samples. Thereby, the quantitative UV-assisted conversion of the rather weak IR-absorber H2S into the more pronouncedly responding SO2 is used for hydrogen sulfide detection. A linear calibration model was established in the range of 7.5 to 100 ppmv achieving a limit of detection at 1.5 ppmv using 10 min of sample preconcentration (onto Molecular Sieve 5A) at a flow rate of 200 mL min(-1). When compared to a conventional UV-conversion system, the iCONVERT revealed similar performance. Considering the potential for system miniaturization using, e.g., dedicated quantum cascade lasers (QCL) in lieu of the FT-IR spectrometer, the developed sensing platform may be further evolved into a hand-held device.
authors.affiliation: São Paulo State University , Department of Analytical Chemistry, UNESP, CEP 14800-970, Araraquara, São Paulo, Brazil.|University of Ulm , Institute of Analytical and Bioanalytical Chemistry, 89081, Ulm, Germany.
authors.forename: João Flavio da Silveira
authors.initials: JF
authors.lastname: Petruci
authors.affiliation: São Paulo State University , Department of Analytical Chemistry, UNESP, CEP 14800-970, Araraquara, São Paulo, Brazil.
authors.forename: Arnaldo Alves
authors.initials: AA
authors.lastname: Cardoso
authors.affiliation: University of Ulm , Institute of Analytical and Bioanalytical Chemistry, 89081, Ulm, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Wilk
authors.affiliation: University of Ulm , Institute of Analytical and Bioanalytical Chemistry, 89081, Ulm, Germany.
authors.forename: Vjekoslav
authors.initials: V
authors.lastname: Kokoric
authors.affiliation: University of Ulm , Institute of Analytical and Bioanalytical Chemistry, 89081, Ulm, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Mizaikoff