TY  - JOUR
A1  - Tippkötter, Nils
A1  - Deterding, A.
A1  - Ulber, Roland
T1  - Determination of acetic acid in fermentation broth by gas-diffusion technique
JF  - Engineering in Life Sciences
N2  - Due to the interfering effects of acetic acid in many fermentation processes, a gas-diffusion technique was developed for the online determination of acetic acid. The measurements were accomplished with a flow diffusion analysis (FDA) unit from the TRACE Analytics GmbH, Braunschweig, Germany. The diffusion analysis is based on the UV-absorbance of acetic acid at 205 nm. The measurement was achieved by the separation of an acceptor and a carrier stream (acidified fermentation broth) using a gas permeable polytetrafluoroethylene (PTFE) membrane, whereby broth constituents that would otherwise disturb the UV-measurement of acetic acid, are held back efficiently. Merely, the fermentation by-products, e.g. formic acid, is capable of diffusing through the membrane. While formic acid can disturb the measurement, carbon dioxide does not absorb at 205 nm. The method operates with time-dependent sample enrichment. During the analysis, a small volume of the acceptor stream is stopped for a defined time interval in the acceptor chamber. During this period, the gaseous acetic acid diffuses through the membrane and is enriched in the acceptor chamber. Subsequently after the enrichment, the acceptor stream flows through a UV-detector. The intensity of the signal is proportional to the acetic acid concentration. Online measurements in bioreactors via a sterile filtration probe have been accomplished. A linear calibration in the range of 0.5–5.0 g/L acetic acid with a relative standard deviation of <5 % was obtained. A sampling rate of 8 samples per hour was possible. The system was applied for the determination of acetic acid in E. coli fermentation broth. The instrument is easy to clean, very user-friendly and does not require any toxic or expensive reagents.
Y1  - 2008
U6  - https://doi.org/10.1002/elsc.200820227
VL  - 8
IS  - 1, Special Issue: Technical Systems for the Use in Life Sciences
SP  - 62
EP  - 67
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
A1  - Sadeghfam, Arash
T1  - Electrically tunable bandpass filter with integrated carrier suppression for UHF RFID systems / Sadeghfam, Arash ; Heuermann, Holger
JF  - European Conference on Wireless Technology, 2008. EuWiT 2008.
Y1  - 2008
SN  - 978-2-87487-008-8
SP  - 306
EP  - 309
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
T1  - Calibration of a Network Analyzer Without a Thru Connection for Nonlinear and Multiport Measurements
JF  - IEEE Transactions on Microwave Theory and Techniques. 56 (2008), H. 11, 1
Y1  - 2008
SN  - 0018-9480
SP  - 2505
EP  - 2510
ER  - 
TY  - JOUR
A1  - Stulpe, Werner
A1  - Busch, Paul
T1  - The structure of classical extensions of quantum probability theory
JF  - Journal of Mathematical Physics. 49 (2008), H. 3
Y1  - 2008
SN  - 1089-7658
N1  - 032104
SP  - 1
EP  - 22
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
T1  - A 14 W SPST Switch with Four PIN-Diodes In a 0402-SMD-Package
Y1  - 2008
SN  - 978-3-8007-3086-5
N1  - Microwave Conference (GeMIC), 2008 German
SP  - 318
EP  - 321
ER  - 
TY  - JOUR
A1  - Schöning, Michael Josef
A1  - Poghossian, Arshak
T1  - Silicon-based field-effect devices for (bio-)chemical sensing
JF  - International Conference on Advanced Semiconductor Devices and Microsystems, 2008. ASDAM 2008
Y1  - 2008
SN  - 978-1-4244-2325-5
SP  - 31
EP  - 38
CY  - Smolenice, Slovakia
ER  - 
TY  - JOUR
A1  - Gun, Jenny
A1  - Schöning, Michael Josef
A1  - Abouzar, Maryam H.
A1  - Poghossian, Arshak
A1  - Katz, Evgeny
T1  - Field-Effect Nanoparticle-Based Glucose Sensor on a Chip: Amplification Effect of Coimmobilized Redox Species
JF  - Electroanalysis. 20 (2008), H. 16
Y1  - 2008
SN  - 1521-4109
SP  - 1748
EP  - 1753
ER  - 
TY  - JOUR
A1  - Beging, Stefan
A1  - Poghossian, Arshak
A1  - Schöning, Michael Josef
A1  - Hataihimakul, Sudkanung
A1  - Busch, H.
A1  - Baldsiefen, G.
A1  - Laube, N.
A1  - Kleinen, L.
A1  - Hosseiny, R.
T1  - Feldeffektbasierender Ca2+-sensitiver Sensor für den Einsatz im Nativurin zur Bestimmung des Harnsteinbildungsrisikos
JF  - Sensoren und Messsysteme 2008 : 14. Fachtagung Ludwigsburg, 11. und 12. März 2008 / VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik
Y1  - 2008
SN  - 978-3-18-092011-5
N1  - VDI-Berichte ; 2011 ; Sensoren und Messsysteme 2008, 14. GMA/ITG-Fachtagung, VDI/VDE- Gesellschaft Mess- und Automatisierungstechnik, + CD-ROM, Ludwigsburg, DE, 11.-12. Mar, 2008
SP  - 775
EP  - 782
PB  - VDI-Verl.
CY  - Düsseldorf
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Abouzar, Maryam H.
A1  - Schöning, Michael Josef
T1  - Capacitance–voltage and impedance characteristics of field-effect EIS sensors functionalised with polyelectrolyte multilayers
JF  - IRBM. 29 (2008), H. 2-3
Y1  - 2008
SN  - 1959-0318
SP  - 149
EP  - 154
ER  - 
TY  - JOUR
A1  - Abouzar, Maryam H.
A1  - Poghossian, Arshak
A1  - Razavi, Arash
A1  - Besmehn, Astrid
A1  - Bijnens, Nathalie
A1  - Williams, Oliver A.
A1  - Haenen, Ken
A1  - Wagner, Patrick
A1  - Schöning, Michael Josef
T1  - Penicillin detection with nanocrystalline-diamond field-effect sensor
JF  - physica status solidi (a). 205 (2008), H. 9
Y1  - 2008
SN  - 1862-6319
N1  - Special Issue: Hasselt Diamond Workshop 2008 - SBDD XIII
SP  - 2141
EP  - 2145
ER  -