TY - CONF A1 - Tiebe, Carlo A1 - Banach, Ulrich A1 - Hübert, Thomas T1 - VDI/VDE-Richtlinie für Multigassensoren N2 - Technische Richtlinien enthalten Empfehlungen sowie Anforderungen zum Stand der Technik zur Aufstellung von Bewertungskriterien und Behandlung wissenschaftlich-technischer Fragen. Sie fördern den Erfahrungsaustausch und Technologietransfer zwischen Entwicklern und Anwendern. In unserem Beitrag stellen wir die Richtlinie VDI/VDE 3518 vor. Diese Richtlinienreihe definiert Begriffe, beschreibt den Aufbau und klassifiziert Multigassensoren (Blatt 1), befasst sich mit den Anforderungen für das Unterscheiden, Erkennen und mengenmäßige Bestimmen von Gemischen gasförmiger Stoffe und die Prüfung von Multigassensoren (Blatt 2) und gibt Anleitung für geruchsbezogene Messungen mit „Elektronischen Nasen“ (Blatt 3). Multigassensoren können als elektronische Nasen in Anlehnung an den biologischen Geruchssinn zur Wahrnehmung und Charakterisierung von Gerüchen eingesetzt werden. Die Spezifik von Multigassensoren besteht darin, dass durch die Wahl und Betriebsweise der Sensoren eine Vielzahl von geeigneten Messsignalen erzeugt werden, aus denen mit mathematischen Verfahren die für die Anwendung gewünschten Informationen extrahiert werden. Dazu ist ein Training der Messeinrichtung mit Proben bekannter Eigenschaften notwendig. Diese Richtlinie soll Herstellern, Anbietern und Nutzern als ein Leitfaden Informationen und Erläuterungen für die korrekte und sichere Arbeit mit Multigassensoren liefern. Sie soll Prüflaboratorien und Anwendern helfen, bei der Beurteilung von Qualitätsmerkmalen einheitlich vorzugehen und dafür gemeinsame Randbedingungen anzugeben T2 - 7. Anwendertreffen Ionenmobilitätsspektrometrie CY - Reutlingen, Germany DA - 06.03.2018 KW - Elektronische Nase KW - Multigassensorik KW - Richtlinie PY - 2018 AN - OPUS4-44452 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tiebe, Carlo A1 - Detjens, Marc A1 - Banach, Ulrich A1 - Hübert, Thomas T1 - Measurement uncertainty of coulometric trace humidity sensors N2 - Especially trace amounts of water vapour in gases can be reliably determined by coulometric trace humidity sensors. The principle of these sensors is based on water vapour absorption in a hygroscopic layer and its subsequent electrolytic decomposition. The calibration of sensors was performed in the humidity range, expressed as frost point temperature, from −30°C to −80°C . This range is equivalent to volume fractions smaller than 376 µL·L−1. Generated humidity was measured with coulometric sensors and a chilled dew point hygrometer that was used as reference. An empirical non-linear function was found between sensor signal and measured reference humidity. This function consists of two parameters with a measurement uncertainty. Both calibration parameters were checked by means of one-way analysis of variance. It showed that gas specific function can be used for humidity measurement in nitrogen, hydrogen, dinitrogen monoxide, compressed and synthetic air. It is possible to determine trace humidity in all tested gases with an expanded uncertainty less than 2.1 K (coverage factor k=2 ) regarding frost point temperature. KW - Trace humidity KW - Coulometric sensor KW - Measurement uncertainty KW - ANOVA PY - 2018 DO - https://doi.org/10.1515/teme-2018-0031 SN - 0171-8096 VL - 85 IS - 12 SP - 746 EP - 753 PB - De Gruyter CY - Oldenbourg AN - OPUS4-45959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tiebe, Carlo A1 - Miessner, H. A1 - Koch, B. A1 - Hübert, Thomas T1 - Detection of microbial volatile organic compounds (MVOCs) by ion-mobility spectrometry N2 - Traces of microbial volatile organic compounds (MVOCs) in air can indicate the presence of growth of moulds in the indoor environment. Ion-mobility spectrometry is a very promising method for detection of these MVOCs, because of its high sensitivity. For development of an in-situ method for detection of MVOCs, a portable ion-mobility spectrometer (IMS) was used and test gases of 14 MVOCs and their respective mixtures were investigated. IMS spectra were recorded as a function of concentration of MVOCs in air. Drift time and mobility of reactant ions formed in positive polarity mode were determined and correlated with the mass-to-charge ratio (m/z) of the MVOCs investigated. The estimated detection limit has a specific value for each MVOC and is in the range 3 to 96 µg m-3 (1 to 52 ppbV). Indoor trials show that IMS can indicate hidden mould growth. KW - Trace gas analysis KW - MVOCs KW - Ion-mobility spectrometry KW - Mould detection PY - 2009 DO - https://doi.org/10.1007/s00216-009-3147-4 SN - 1618-2642 SN - 1618-2650 VL - 395 IS - 7 SP - 2313 EP - 2323 PB - Springer CY - Berlin AN - OPUS4-20082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tiebe, Carlo A1 - Hübert, Thomas A1 - Lorek, A. A1 - Wernecke, R. T1 - HUMItrace-Sensorsystem mit neuartigen planaren Spurenfeuchtesensoren N2 - Es wird ein Sensorsystem (HUMItrace III) zur Spurenfeuchtebestimmung in der Prozessmesstechnik vorgestellt. Die Bestimmung der Spurenfeuchte erfolgt mit neuentwickelten planaren Sensoren (HUMItrace-Sensoren) nach dem coulometrischen Messprinzip im Frostpunkttemperaturbereich von -80 °C bis -30 °C mit der Kalibriereinrichtung THG11 durch Mischen von trockenen und befeuchteten Teilgasströmen kalibriert. Die Gasfeuchte von Luft kann in diesem Bereich mit den HUMItrace-Sensoren mit einer erweiterten Unsicherheit von 2 K bestimmt werden. Die Sensoren können aber auch zur Gasfeuchtemessung in Wasserstoff, Stickstoff und Distickstoffmonoxid eingesetzt werden. Eine weitere Kalibriereinrichtung, THG-P12, generiert Prüfgase nach der Permeationsmethode; sie kann in das HUMItrace III Sensorsystem implementiert und zur vor-Ort-Kalibrierung der HUMItrace-Sensoren nach dem Standardadditionsverfahren genutzt werden. T2 - Temperatur 2013 - Verfahren und Geräte in der Temperatur- und Feuchtemesstechnik CY - Berlin, Germany DA - 05.06.2013 PY - 2013 SN - 3-9810021-8-0 SP - 257 EP - 262 AN - OPUS4-28732 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Hübert, Thomas A1 - Tiebe, Carlo A1 - Banach, Ulrich ED - Rodriguez Mendez, M. T1 - Electronic Noses for the Quality Control of Spices N2 - The chapter describes the application of electronic noses (multigas sensors) for the quality control of spices and spice mixtures. Electronic noses were successfully applied for headspace analysis of spices. It was demonstrated in many investigations that electronic noses can contribute to the characterization of spices and spice mixtures in order to distinguish spices and spice mixtures, differentiate by origin, growth seasons,and processing,indicate adulteration from original, detect mold infestation. Electronic noses can be used as a fast screening method to provide information about the product quality. However, it needs samples and methods for reference, careful training, and complex calibration to consider influencing and disturbing effects as well as the possible limitations of the instrumentation. The correlation to classical chemical analysis methods is always advisable. Machined olfaction methods are capable to support the sensory analysis; however, they cannot yet substitute them. KW - Spice KW - Electronic Nose KW - Multigas sensor KW - Quality control PY - 2016 SN - 978-0-12-800243-8 DO - https://doi.org/10.1016/B978-0-12-800243-8.00012-3 SP - Chapter 12, 115 EP - 124 PB - Academic Press CY - Oxford AN - OPUS4-35443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Banach, Ulrich A1 - Tiebe, Carlo A1 - Hübert, Thomas T1 - Multigas sensors for the quality control of spice mixtures N2 - Spices have an important impact on daily aliment. Changes of their quality resulting in far reaching consequences in different foodstuffs and imply financial losing and even health hazard. In this study it is demonstrated that application of two different portable multi gas sensors (electronic nose and ion mobility spectrometer) supported by multivariate data analysis can contribute to ensure quality control of spice mixtures and to find out product adulteration. Headspace above spice mixtures for sausages and saveloy and product counterfeitings was investigated by a metal oxide based electronic nose (e-nose of KAMINA-type). Linear discriminant analysis (LDA) of sensor resistivity data was performed for differentiation. Simultaneously an ion mobility spectrometer (IMS) was coupled to the emission chamber for detection of gaseous components above spice mixtures. The measured spectra show differences between the two spice mixtures and were discussed using a principal component analysis (PCA). The two multigas sensors permit discrimination between the types of spice mixtures and can indicate product adulteration. Additionally, a headspace gas analysis by gas chromatography was performed to identify the main volatile components and to prove the chemical basis for the observed differences of the multi gas sensors. KW - Spice mixtures KW - Product adulteration KW - Electronic nose KW - Ion mobility spectrometer KW - Gas chromatography KW - Multivariate data analysis PY - 2012 DO - https://doi.org/10.1016/j.foodcont.2012.01.015 SN - 0956-7135 VL - 26 IS - 1 SP - 23 EP - 27 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-25402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübert, Thomas T1 - In-situ calibration system for trace humidity sensors T2 - TEMPMEKO 2013 - Symposium on Temperature and Thermal Measurements in Industry ans Science CY - Fuchal, Spain DA - 2013-10-14 PY - 2013 AN - OPUS4-30130 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tahri, K. A1 - Tiebe, Carlo A1 - Bougrini, M. A1 - Saidi, T. A1 - El Alami El Hassani, N. A1 - El Bari, N. A1 - Hübert, Thomas A1 - Bouchikhi, B. T1 - Characterization and discrimination of saffron by multisensory systems, SPME-GC-MS and UV-Vis spectrophotometry N2 - Different electronic sensor systems coupled with multivariate data analysis were applied to characterize and classify seven saffron samples and to verify their declared geographical origin. The proposed electronic sensing consists of a low-cost electronic nose (E-nose) based on metal oxide semiconductor sensors and a voltammetric electronic tongue (VE-tongue) based on voltammetric sensors. The ability of multivariable analysis methods such as Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA) and Support Vector Machines (SVMs) to classify the saffron samples according to their geographical origin have been investigated. Both PCA and HCA have shown an overlapping of E-nose responses. Moreover, the SVM analysis of the E-nose database reached a 66.07% success rate in the recognition of the saffron sample odour. On the other hand, good discrimination has been reached using PCA and HCA in the VE-tongue characterization case, besides a 100% accuracy in the saffron flavour recognition was attained. To validate the proposed electronic sensing systems, analytical chemical methods such as SPME-GC-MS and UV-Vis spectrophotometry were used. These analytical methods could be helpful tools to identify the composition of volatile compounds of the analysed saffron samples. Moreover, UV-Vis spectrophotometry was also used to determine the non-volatile profile of the samples from different geographic origins. It is demonstrated that the electronic sensing systems' findings are in a satisfactory correlation with the analytical methods. In the light of these results, we might say that the electronic systems offer a fast, simple and efficient tool to recognize the declared geographical origin of the saffron samples. KW - Electronic nose KW - Voltammetric electronic tongue KW - SPME-GC-MS KW - UV-vis spectrophotometry KW - Saffron KW - Geographic differentiation KW - Multivariable analysis PY - 2015 DO - https://doi.org/10.1039/C5AY01986A SN - 1759-9660 SN - 1759-9679 VL - 7 IS - 24 SP - 10328 EP - 10338 PB - RSC Publ. CY - Cambridge AN - OPUS4-35174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lang, Cindy A1 - Hübert, Thomas T1 - A colour ripeness indicator for apples N2 - Ripeness and senescence of climacteric fruits are strongly related to the emission of ethylene gas. The ethylene emission of apples can be detected by a new developed ripeness indicator. This indicator is based on the reduction effect of ethylene causing colour changes in selected metal ions. The used molybdenum (Mo) chromophores change under the impact of ethylene in a colour spectrum from white/light yellow to blue because of a partial reduction of Mo(VI) to Mo(V). The sensitivity of molybdenum colour change reactions can be varied by composition and pH values (pH 1.4–pH 1.5) of used ammonium molybdate solution and thus adopted to different fruits and storage conditions. The indicator can be combined with a colour recognition sensor for quantitative measurements of colour change in the frame of the L*a*b* model. The b*-coordinate, reflecting changes from yellow to blue, and the luminance L* continuously vary with increasing ethylene emission. Results obtained with the indicator system were compared with direct determination of ethylene concentrations by gas chromatography (GC-FID). Furthermore, a descriptive sensory test was used to estimate the degree of ripeness. The indicator can be applied for ripeness gauge on single fruit or in paperboard crates. KW - Ripeness KW - Apples KW - Ethylene KW - Molybdenum blue KW - Indicator PY - 2012 DO - https://doi.org/10.1007/s11947-011-0694-4 SN - 1935-5149 SN - 1935-5130 VL - 5 IS - 8 SP - 3244 EP - 3249 PB - Springer Science + Business Media CY - New York, NY, USA AN - OPUS4-26979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -