TY - CHAP A1 - Barek, Jiri A1 - Fischer, Jan A1 - Navratil, Tomas A1 - Peckova, Karolina A1 - Yosypchuk, Bogdan T1 - Silver solid amalgam electrodes as sensors for chemical carcinogens N2 - The applicability of differential pulse voltammetry (DPV) and adsorptive stripping voltammetry (AdSV) at a non-toxic meniscus-modified silver solid amalgam electrode (m-AgSAE) for the determination of trace amounts of genotoxic substances was demonstrated on the determination of micromolar and submicromolar concentrations of 3-nitrofluoranthene using methanol - 0.01 mol L-1 NaOH (9:1) mixture as a base electrolyte and of Ostazine Orange using 0.01 mol L-1 NaOH as a base electrolyte. KW - Biosensor KW - Solid amalgam electrodes KW - voltammetry KW - carcinogens KW - 3-nitrofluoranthene KW - Ostazine Orange Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1554 ER - TY - CHAP A1 - Arida, Hassan A. A1 - Kloock, Joachim P. A1 - Schöning, Michael Josef T1 - Novel organic membrane-based thin-film microsensors for the determination of heavy metal cations N2 - A first step towards the fabrication and electrochemical evaluation of thin-film microsensors based on organic PVC membranes for the determination of Hg(II), Cd(II), Pb(II) and Cu(II) ions in solutions has been realised. The membrane-coating mixture used in the preparation of this new type of microsensors is incorporating PVC as supporting matrix, o-nitrophenyloctylether (o-NPOE) as solvent mediator and a recently synthesized Hg[dimethylglyoxime(phene)]2+ and Bis-(4-hydroxyacetophenone)-ethylenediamine as electroactive materials for Hg(II) and Cd(II), respectively. A set of three commercialised ionophores for Cd(II), Pb(II) and Cu(II) has been also used for comparison. Thin-film microsensors based on these membranes showed a Nernstian response of slope (26-30 mV/dec.) for the respective tested cations. The potentiometric response characteristics (linear range, pH range, detection limit and response time) are comparable with those obtained by conventional membranes as well as coated wire electrodes prepared from the same membrane. The realisation of the new organic membrane-based thin-film microsensors overcomes the problem of an insufficient selectivity of solid-state-based thinfilm sensors. KW - Biosensor KW - Heavy metal detection KW - thin-film microsensors KW - organic PVC membranes Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1545 ER - TY - CHAP A1 - Pijanowska, Dorota G. A1 - Remiszewska, Elzbieta T1 - pH-based detection of phenylalnine by potentiometric and colorimetric methods N2 - In this paper, methods of sample preparation for potentiometric measurement of phenylalanine are presented. Basing on the spectrophotometric measurements of phenylalanine, the concentrations of reagents of the enzymatic reaction (10 mM L-Phe, 0,4 mM NAD+, 2U L-PheDH) were determined. Then, the absorption spectrum of the reaction product, NADH, was monitored (maximum peak at 340 nm). The results obtained by the spectrophotometric method were compared with the results obtained by the colourimetry, using pH indicators. The above-mentioned two methods will be used as references for potentiometric measurements of phenylalanine concentration. KW - Biosensor KW - Phenylalanine determination KW - enzymatic methods KW - pH-based biosensing Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1536 ER - TY - CHAP A1 - Katz, Eugenii A1 - Willner, Itamar T1 - Magneto-controlled quantized electron transfer to surface-confined redox units and metal nanoparticles N2 - Hydrophobic magnetic nanoparticles (NPs) consisting of undecanoate-capped magnetite (Fe3O4, average diameter ca. 5 nm) are used to control quantized electron transfer to surface-confined redox units and metal NPs. A two-phase system consisting of an aqueous electrolyte solution and a toluene phase that includes the suspended undecanoatecapped magnetic NPs is used to control the interfacial properties of the electrode surface. The attracted magnetic NPs form a hydrophobic layer on the electrode surface resulting in the change of the mechanisms of the surface-confined electrochemical processes. A quinone-monolayer modified Au electrode demonstrates an aqueous-type of the electrochemical process (2e-+2H+ redox mechanism) for the quinone units in the absence of the hydrophobic magnetic NPs, while the attraction of the magnetic NPs to the surface results in the stepwise single-electron transfer mechanism characteristic of a dry nonaqueous medium. Also, the attraction of the hydrophobic magnetic NPs to the Au electrode surface modified with Au NPs (ca. 1.4 nm) yields a microenvironment with a low dielectric constant that results in the single-electron quantum charging of the Au NPs. KW - Biosensor KW - Nanoparticles KW - magnetic particles KW - quantum charging KW - modified electrode Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1528 ER - TY - CHAP A1 - Spannhake, Jan A1 - Schulz, Olaf A1 - Helwig, Andreas A1 - Krenkow, Angelika A1 - Müller, Gerhard A1 - Doll, Theodor T1 - High-temperature MEMS heater platforms: long-term performance of metal and semiconductor heater materials N2 - Micromachined thermal heater platforms offer low electrical power consumption and high modulation speed, i.e. properties which are advantageous for realizing nondispersive infrared (NDIR) gas- and liquid monitoring systems. In this paper, we report on investigations on silicon-on-insulator (SOI) based infrared (IR) emitter devices heated by employing different kinds of metallic and semiconductor heater materials. Our results clearly reveal the superior high-temperature performance of semiconductor over metallic heater materials. Long-term stable emitter operation in the vicinity of 1300 K could be attained using heavily antimony-doped tin dioxide (SnO2:Sb) heater elements. KW - Biosensor KW - Hotplate KW - heater metallisation KW - high-temperature stability KW - electro-migration KW - doped silicon KW - doped metal oxide KW - antimony doped tin oxide Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1513 ER - TY - CHAP A1 - Tymecki, Lukasz A1 - Glab, Stanislaw A1 - Koncki, Robert T1 - Miniaturized, planar ion-selective electrodes fabricated by means of thick-film technology N2 - Various planar technologies are employed for developing solid-state sensors having low cost, small size and high reproducibility; thin- and thick-film technologies are most suitable for such productions. Screen-printing is especially suitable due to its simplicity, low-cost, high reproducibility and efficiency in large-scale production. This technology enables the deposition of a thick layer and allows precise pattern control. Moreover, this is a highly economic technology, saving large amounts of the used inks. In the course of repetitions of the film-deposition procedure there is no waste of material due to additivity of this thick-film technology. Finally, the thick films can be easily and quickly deposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodes based on ionophores as well as crystalline ion-selective materials dedicated for potentiometric measurements are demonstrated. Analytical parameters of these sensors are comparable with those reported for conventional potentiometric electrodes. All mentioned thick-film strip electrodes have been totally fabricated in only one, fully automated thickfilm technology, without any additional manual, chemical or electrochemical steps. In all cases simple, inexpensive, commercially available materials, i.e. flexible, plastic substrates and easily cured polymer-based pastes were used. KW - Biosensor KW - Potentiometry KW - thick-film technology KW - screen-printing KW - ion-selective electrodes Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1506 ER - TY - CHAP A1 - Bukhari, Syed Faisal Ahmed A1 - Yang, Wuqiang T1 - Multi-interface level sensors and new development in monitoring and control of oil separators N2 - In the oil industry, huge saving may be made if suitable multi-interface level measurement systems are employed for effectively monitoring crude oil separators and efficient control of their operation. A number of techniques, e.g. externally mounted displacers, differential pressure transmitters and capacitance rod devices, have been developed to measure the separation process with gas, oil, water and other components. Because of the unavailability of suitable multi-interface level measurement systems, oil separators are currently operated by the trial-and-error approach. In this paper some conventional techniques, which have been used for level measurement in industry, and new development are discussed. KW - Biosensor KW - Level sensor KW - multi-interface measurement KW - electrical capacitance tomography KW - ECT Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1498 ER - TY - CHAP A1 - Pijanowska, Dorota G. A1 - Remiszewska, Elzbieta A1 - Pederzolli, Cecilia A1 - Lunelli, Lorenzo A1 - Vendano, Michele A1 - Canteri, Roberto A1 - Dudzinski, Konrad A1 - Kruk, Jerzy A1 - Torbicz, Wladyslaw T1 - Surface modification for microreactor fabrication N2 - In this paper, methods of surface modification of different supports, i.e. glass and polymeric beads for enzyme immobilisation are described. The developed method of enzyme immobilisation is based on Schiff’s base formation between the amino groups on the enzyme surface and the aldehyde groups on the chemically modified surface of the supports. The surface of silicon modified by APTS and GOPS with immobilised enzyme was characterised by atomic force microscopy (AFM), time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and infrared spectroscopy (FTIR). The supports with immobilised enzyme (urease) were also tested in combination with microreactors fabricated in silicon and Perspex, operating in a flow-through system. For microreactors filled with urease immobilised on glass beads (Sigma) and on polymeric beads (PAN), a very high and stable signal (pH change) was obtained. The developed method of urease immobilisation can be stated to be very effective. KW - Biosensor KW - Microreactors KW - surface modification KW - enzyme immobilisation KW - lab-on-a-chip Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1480 ER - TY - CHAP A1 - Platen, Johannes A1 - Poghossian, Arshak A1 - Schöning, Michael Josef T1 - Microstructured Nanostructures – nanostructuring by means of conventional photolithography and layer-expansion technique N2 - A new and simple method for nanostructuring using conventional photolithography and layer expansion or pattern-size reduction technique is presented, which can further be applied for the fabrication of different nanostructures and nano-devices. The method is based on the conversion of a photolithographically patterned metal layer to a metal-oxide mask with improved pattern-size resolution using thermal oxidation. With this technique, the pattern size can be scaled down to several nanometer dimensions. The proposed method is experimentally demonstrated by preparing nanostructures with different configurations and layouts, like circles, rectangles, trapezoids, “fluidic-channel”-, “cantilever”- and meander-type structures. KW - Biosensor KW - Nanostructuring KW - layer expansion KW - pattern-size reduction KW - self-aligned patterning Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1477 ER - TY - CHAP A1 - Förster, Arnold A1 - Stock, Jürgen A1 - Montanari, Simone A1 - Lepsa, Mihail Ion A1 - Lüth, Hans T1 - Fabrication and characterisation of GaAs Gunn Diode Chips for applications at 77 GHz in automotive industry N2 - GaAs-based Gunn diodes with graded AlGaAs hot electron injector heterostructures have been developed under the special needs in automotive applications. The fabrication of the Gunn diode chips was based on total substrate removal and processing of integrated Au heat sinks. Especially, the thermal and RF behavior of the diodes have been analyzed by DC, impedance and S-parameter measurements. The electrical investigations have revealed the functionality of the hot electron injector. An optimized layer structure could fulfill the requirements in adaptive cruise control (ACC) systems at 77 GHz with typical output power between 50 and 90 mW. KW - Biosensor KW - Gunn diode KW - microwave generation KW - GaAs hot electron injector Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:a96-opus-1462 ER -