Quartz micro balance

Quartz micro balance with dendritic sensor layers... 

Fig. 8.10 Mode of operation of the quartz micro balance (left schematic). Right A dendrimer as guest-selective host compound (selector) for coating of the quartz crystal oscillator. Red Selector layer green various analyte components...

Fig. 8.11 Dendrimer with six terminal platinum-chelate complex units for S02 detection by the quartz micro balance (according to Albrecht, Schlupp, Bargon, van Koten et a. )...

The necessary porosity for thicker layers was introduced by appropriate current densities [321-323], by co-deposition of composites with carbon black [28, 324] (cf. Fig. 27), by electrodeposition into carbon felt [28], and by fabrication of pellets from chemically synthesized PPy powders with added carbon black [325]. Practical capacities of 90-100 Ah/kg could be achieved in this way even for thicker layers. Self-discharge of PPy was low, as mentioned. However, in lithium cells with solid polymer electrolytes (PEO), high values were reported also [326]. This was attributed to reduction products at the negative electrode to yield a shuttle transport to the positive electrode. The kinetics of the doping/undoping process based on Eq. (59) is normally fast, but complications due to the combined insertion/release of both ions [327-330] or the presence of a large and a small anion [331] may arise. Techniques such as QMB/CV(Quartz Micro Balance/Cyclic Voltammetry) [331] or resistometry [332] have been employed to elucidate the various mechanisms. 

The Au films were evaporated from different resistively heated sources as well as from an electron beam evaporator. The Au frlm thicknesses and the growth rates were determined during growth by a quartz micro balance. 

Chemical sensors have been reported that are based on quartz micro balances or surface acoustic wave oscillators coated with the trimethylsilyl ethers of and 6 " and that are claimed to detect various solvent vapors in ppm amounts. ... 

Apples [26] Monitoring post-harvest ripening 12 quartz micro balance sensors... 

Corylus avellana L. [85] Identification of flavor of natural and roasted Turkish hazelnut varieties 8 quartz micro balance sensors and 8 metal oxide sensors... 

Radeva E, Georgiev V, Spassov L, Koprinarov N, St K (1997) Humidity adsorptive properties of thin fullerene layers studied by means of quartz micro-balance. Sens Actuators B 42 11-13 Ramos MV, Al-Jumady A, Puli VS (2005) Conductive polymer-composite sensor for gas detection, In Proceedings of 1st international conference on sensing technology, Palmerston North, New Zealand, 21-23 November 2005, p 213-216... 

The amorphous material was evaporated in-situ, in a preparation chamber attached to the main measuring unit, from pinhole-sources onto fresh deposited Au films on flat silicon wafers. Film thickness was monitored with a quartz micro-balance (120 nm). During the evaporations the pressure increased up to 10 mbar. The direct transfer from the preparation chamber to the measuring unit was possible, without breaking the vacuum, using a magnetic transfer line. 

Metal-solution interface, quantum mechanical calculations for (Kripsonsov), 174 Metal-water affinity, 177 Micro-balance, quartz crystal, 578 Microwave circuit, 446 for Faraday rotation, 454 Microwave conductivity... 

Quantum chemical calculations, 172 Quantum chemical method, calculations of the adsorption of water by, 172 Quantum mechanical calculations for the metal-solution interface (Kripsonsov), 174 and water adsorption, 76 Quartz crystal micro-balance, used for electronically conducting polymer formation, 578... 

An application of an electrochemical quartz crystal microbalance (EQCM) in the study of the A11/HCIO4 system shows that even at a potential about 0.5 V more negative than the onset of AuO formation (the so-called preoxide region), the resonant frequency of the Au-covered quartz crystal decreases as that of the surface mass increases. A comparison of a voltammogram with the potential dependence of the micro-balance frequency for an Au electrode is shown in Figs. 6a and 6b. 

Rideal and his collaborators found that solid particles of protein spread very rapidly on a clean surface their method of spreading is to coat a quartz fibre, first covered with paraffin wax, with a little protein this is dipped into the water surface, and the amount of protein passing into the surface ascertained by weighing the fibre on a simple micro-balance.1 By this method somewhat larger areas can sometimes be obtained, and films formed from proteins which cannot be made to form homogeneous films when spread by Gorter s technique and in certain cases the average thickness of the fully spread film is only about 3 A. 

In this paper we present a brief topical account of the kinetic possibilities and limitations of the EQCM. Extensive review chapters with theoretical aspects of the quartz crystal micro-balance have been written by Buttry and Ward [3-5] and the reader is referred to them for a more detailed discussion. 

The quartz crystal micro-balance (QCM), the most extensively studied shear mode AT-cut quartz resonator, is comprised of a thin slice of quartz single crystal with two metal electrodes deposited on both faces of the crystal. These excitation electrodes generate a transverse shear wave across the thickness of the crystal that propagates into the film immobilized onto the crystal surface. When the over-layer is non-rigidly coupled to the... 

Adsorption isotherms were determined on a Cahn 1000 vacuum micro-balance system, using a Leybold-Heraeus Turbotronic TMP 120 turbomolecular pump for evacuation and a variable-leak valve for adsorbate gas injection. Approximately 0.3 grams of the sodium-exchanged zeolite was placed into a 1 cm. diameter hemispherical quartz sample pan within the adsorption chamber... 

Quartz crystal micro balance shows promise in its applications for chemical sensing. A proper and selective coating on the surface of a QCM can be used to selectively absorb a chemical species. The mass of the absorbed species, even in very minute quantity, can be used to quantify the species present. It is an effective means for chemical sensing under appropriate circumstance. 

Smith, A.L., Shirazi, H.M., and Mulligan, S.R. Water sorption isotherms and enthalpies of water sorption by lysozyme using the quartz crystal micro-balance/Heat-conduction calorimeter, Biochim. Biophys. Acta — Protein Struct. Mol. Enzymol., 1594,150, 2002. 

L. Alfonta, I. WQlna-, D.J. Throckmorton, and A.K. Singh, Electrochemical and quartz crystal micro-balance detection of the cholera toxin employing horseradish peroxidase and GMl-functionalized Upo-somes. Anal. Chem. 73,5287-5295 (2001). 

Liu, M.-H. and Y.O. Su (1999). Electrocatalytic reactions by an iron porphyrin/ polypyrrole modified electrode monitored by electrochemical quartz crystal micro-balance. J. Chin. Chem. Soc. 46,115-119. 

In this work, a silane-derivatized dithiocarbamate iniferter was utilized to prepare PMAA brushes on Si/Si02 surfaces under UV irradiation. The combination of the photoiniferter-mediated photopolymerization with a UV-LED source appears to be ideally suited to the direct preparation of polyelectrolyte brushes with minimal free polymer formation during brash synthesis. Following characterization of the PMAA brushes by means of surface-analytical techniques, such as quartz crystal micro-balance with dissipation monitoring (QCM-D), spectroscopic ellipsometry, and static contact-angle measurements, the PMAA brushes were demonstrated to enhance aqueous lubrication of Si/ Si02 under low-contact-pressure conditions. 

Figure 8.5 Quartz crystal micro balance design.

Vikinge TP, et al. Comparison of surface plasmon resonance and quartz crystal micro-balance in the smdy of whole blood and plasma coagulation. Biosens Bioelectron 2000 15 605-13. 

It is worth mentioning that corrosion processes can be investigated in more detail by the use of the electrochemical quartz crystal micro balance (EQCM) [291, 292). Mass changes on the electrode result in very sensitive changes in the resonance frequency of the quartz crystal. Increase of mass, for example, passivation by LiPF or LiDFOB, results in frequency decrease (see Figure 17.8b), whereas corrosion of the surface due to LiOTf is accompanied by mass decrease and a strong frequency increase (see Figure 17.9b) [243]. 

Gahai R, SaUacan N, Chegel V, Bourenko T, Katz E, WiUner I. Characterization of the swelling of acrylamidophenylboronic acid-acrylamide hydrogels upon interaction with glucose by Faradaic impedance spectroscopy, chronopotentiometry, quartz-crystal micro-balance (QCM), and surface plasmon resonance (SPR) experiments. J Phys Chem B 2001 105 8196-8202. 

Jia K, Adam PM, lonescu RE (2013) Sequential acoustic detection of atrazine herbicide and carbofuran insecticide using a single micro-structured gold quartz crystal micro balance. SensOT Actuator B 188 400-404... 

Liang C, Yuan C-Y, Warmack RJ, Barnes CE, Dai S (2(X)2) Ionic liquids a new class of sensing materials for detection of organic vapors based on the use of a quartz crystal micro-balance. Anal Chem 74(9) 2172-2176. doi 10.1021/ac011007h... 

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