@inproceedings{MelekhovAbbLechneretal., author = {Melekhov, Evgeny and Abb, Valerius and Lechner, Alfred and Kammler, Martin}, title = {Development of a glass-fiber-based spectrometer for the determination of drug residues in groundwater}, series = {Tagungsband 2. Symposium Elektronik und Systemintegration ESI 2020 "Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung"}, booktitle = {Tagungsband 2. Symposium Elektronik und Systemintegration ESI 2020 "Intelligente Systeme und ihre Komponenten: Forschung und industrielle Anwendung"}, editor = {Ivanov, Artem and Bicker, Marc and Patzelt, Peter}, isbn = {978-3-9818439-4-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:860-opus4-2174}, pages = {101 -- 109}, abstract = {Within the scope of this project, a portable measuring device has been developed which enables a cost-effective analysis of organic substances from ppm to sub-ppm range, such as drug residues in groundwater. The measurement is carried out by means of a surface-enhanced Raman scattering effect (SERS effect) and an exchangeable sensor head. The sensor head used is a nanostructured optical glass fiber glued into a fiber cannula. The tip of the fiber has been processed to act as a SERS cell. The fiber cannula is connected to a freely movable patch cable by using an adapter. Para-thiocresol is used to characterize the SERS cells.}, language = {en} } @misc{MelekhovAbbWeidaueretal., author = {Melekhov, Evgeny and Abb, Valerius and Weidauer, Tobias and Kammler, Martin and Lechner, Alfred}, title = {Tunable Nanopillars as Surface Enhanced Raman Scattering (SERS) Active Structure for Optical Quartz Glass Fiber}, series = {SMSI 2021 - Sensors and Instrumentation}, journal = {SMSI 2021 - Sensors and Instrumentation}, publisher = {AMA Association for Sensors and Measurement}, isbn = {978-3-9819376-4-0}, doi = {10.5162/SMSI2021/B8.2}, pages = {153 -- 154}, abstract = {In this work, a simple cost effective method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas on a tip of an optical quartz glass fiber is described. The structures are prepared using lithography-less dry etching. Gold nanoparticles are used as an etching mask using a thin metal-film thermal dewetting technique. The structures are applied as sensor for label-free analysis of organic substances in ppb range, such as drug residues in groundwater. The measurements are carried out by means of a Surface-enhanced Raman scattering (SERS) effect, an exchangeable sensor head, and a portable Raman device. This method allows in situ applications. Parathiocresol is used as a model substance to characterize the SERS cells. For metallization, gold and silver are compared. Reproducible SERS enhancement factors up to 10 7 are evaluated.}, language = {en} } @inproceedings{BlahnikovaMuellerWaasetal., author = {Blahn{\´i}kov{\´a}, Barbora and M{\"u}ller, D. and Waas, M. and Lechner, Alfred}, title = {Multilyzer - microfluidic online measuring system for the analysis of environmentally relevant substances}, series = {AMA Conferences 2017 : Proceedings : SENSOR 2017 / N{\"u}rnberg 2017-05-30 - 2017-06-01}, booktitle = {AMA Conferences 2017 : Proceedings : SENSOR 2017 / N{\"u}rnberg 2017-05-30 - 2017-06-01}, publisher = {AMA Service GmbH}, address = {Wunstorf}, isbn = {978-3-9816876-4-4}, doi = {10.5162/sensor2017/P5.2}, pages = {696 -- 699}, language = {en} } @article{MelekhovPennWeidaueretal., author = {Melekhov, Evgeny and Penn, Tatjana and Weidauer, Tobias and Abb, Valerius and Kammler, Martin and Lechner, Alfred}, title = {Tunable nanopillar array on a quartz-fiber tip for surface enhanced Raman scattering (SERS) detection}, series = {tm - Technisches Messen}, volume = {89}, journal = {tm - Technisches Messen}, number = {1}, publisher = {de Gruyter}, doi = {10.1515/teme-2021-0093}, pages = {70 -- 81}, abstract = {In this work, a simple two-step method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas directly on the tip of an optical quartz glass fiber is described. The structures are prepared by using dry etching of the fiber tip. For the etching process, gold nanoparticles fabricated by thermal dewetting technique were used as template. The structures are applied as sensors for label-free analysis of organic substances in ppb range, such as drug residues in liquid solutions. The measurements are carried out by a portable Raman device with an exchangeable sensor head utilizing the SERS-effect. This method allows in situ applications. In order to characterize the SERS cells, para-thiocresol and diclofenac sodium are used as model substances. For optimization of the substrate performance, different thicknesses of the dewetting-layer (6, 9, 12 nm), different etching times for formation of the pillars (6, 8, 10 and 12 min), and different thicknesses of SERS-metallization (25, 50, 75 nm) of gold and silver are compared. In order to show the applicability of the structure on the tip of a fiber, measurements from the upper side and from the underside of the substrate on quartz plates are compared. Reproducible SERS enhancement factors up to 10 7 {10^{7}} were achieved.}, language = {en} } @incollection{BlahnikovaMuellerWaasetal., author = {Blahn{\´i}kov{\´a}, Barbora and M{\"u}ller, D. and Waas, M. and Lechner, Alfred}, title = {Multilyzer - Mikrofluidisches Echtzeitmesssystem f{\"u}r die Analyse umweltrelevanter Substanzen}, series = {7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, M{\"u}nchen}, booktitle = {7. MikroSystemTechnik Kongress "MEMS, Mikroelektronik, Systeme", 23.-25. Oktober 2017, M{\"u}nchen}, publisher = {VDE-Verlag}, address = {M{\"u}nchen}, isbn = {978-3-8007-4491-6}, pages = {382 -- 385}, abstract = {Die {\"u}berm{\"a}ßige Verwendung von stickstoffbasierten D{\"u}ngemitteln in der Landwirtschaft stellt eine Gef{\"a}hrdung f{\"u}r die Umwelt und Lebewesen dar. So ist die Analyse von Boden- und Grundwasser zu einem wesentlichen Bestandteil der Nachhaltigkeit und der {\"o}kologischen Erhaltung geworden. Daf{\"u}r bietet der Multilyzer eine passende L{\"o}sung. Der Multilyzer ist ein mikrofluidisches Analysesystem zur Bestimmung niedrigster Konzentrationen von Nitrat, Nitrit und Ammonium, die alle wesentliche Bestandteile des Stickstoffkreislaufs sind. Welche bei {\"U}berm{\"a}ßiger Aufnahme im K{\"o}rper krebserregend wirken und den Sauerstofftransport im Blutkreislauf st{\"o}ren. Der Aufbau ist eine Kombination aus Absorptions- und Fluoreszenzspektroskopie. Der Betrieb mit einer 12 Volt Batterie erm{\"o}glicht die Verwendung des Multilyzer-Systems zur Online-Messung im Feld. Somit k{\"o}nnen sehr kurze Analysezeiten realisiert und der Einfluss von Umwandlungs- bzw. Abbauprozessen vermieden werden. Das gesamte Messsystem wird im Kompetenzzentrum Nanochem an der OTH Regensburg entwickelt, inklusive Fertigungstechnologien, Software- und Hardwaresteuerung.}, language = {de} }