Polymeric membrane sensors

Concentration range of the most important ions in blood and compositions of the corresponding polymeric membrane sensors and their selectivities... 

Fluorinated polymers, especially polytetrafluoroethylene (PTFE) and copolymers of tetrafluoroethylene (TFE) with hexafluoropropylene (HFP) and perfluorinated alkyl vinyl ethers (PFAVE) as well as other fluorine-containing polymers are well known as materials with unique inertness. However, fluorinated polymers with functional groups are of much more interest because they combine the merits of pefluorinated materials and functional polymers (the terms functional monomer/ polymer will be used in this chapter to mean monomer/polymer containing functional groups, respectively). Such materials can be used, e.g., as ion exchange membranes for chlorine-alkali and fuel cells, gas separation membranes, solid polymeric superacid catalysts and polymeric reagents for various organic reactions, and chemical sensors. Of course, fully fluorinated materials are exceptionally inert, but at the same time are the most complicated to produce. 

Another key step is the proper development of surface chemistry to attach addressable probes onto different membrane sensors. This can be achieved by patterning UV-curable acrylic-based polymers inside the microfluidic channel doped with different monomers containing charged or functional groups. Such polymers are ion-selective and provide reactive chemical groups on their surfaces for the attachment of DNA/RNA probes. The functionality of aU the devices proposed here relies on the ion-selectivity of the polymeric material, which is less dependent on... 

Shahinpoor and Moj aired used ion-exchange materials and membranes to produce electrically responsive actuators [41—48] and also encapsulated ion-exchange membrane sensor/actuators. Shahinpoor used electrically responsive polymers coupled with springs and other mechanical devices to improve upon electrically responsive actuators [52] and ionic polymeric conductor composites and ionic polymer metal composites to drive pumps and mini-pumps [41]. 

In this chapter, the on-going research into the effects of the polymeric system on the performance of the fluorescent electrospun polymer nmutfibrous membrane sensors for the detection of 2,4-dinitrotoluene are discussed. 

E.H. El-Naby, Polymeric membrane sensors for the selective determination of dextromethorphan in pharmaceutical preparations. Analytical Sciences, 24 (11), 1409-1414, 2008. 

A FI multisensor system comprising potentiometric sensors of different types for the determination of free cyanide activity in basic solutions for extraction of noble metals has been developed [35]. Solvent polymeric membrane sensors based on metalloporphyrin and crystalline sensors were combined in the sensor system. The sensors of different types were built into the system to form a multisensor detector. The FI multisensor was also beneficial due to computerizing of measurements, automatic sampling, and sample treatment and also due to minimizing amounts of reagents. Preparation of sensor membranes is described below. 

Arvand, M Kermanian, M. and Zanjanchi, M.A. (2010) Direct determination of aluminium in foods and pharmaceutical preparations by potentiometry using an AlMCM-41 modified polymeric membrane sensor. Electrochim. Acta, 55, 6946-6952. 

Javanbakht, M Ganjali, M.R., Norouzi, P. et al. (2008) Development of polymeric membrane sensor for the determination of histamine experimental and theoretical study. Anal. Lett., 41, 619-639. 

Guerreiro, J. R. L., A. H. Kamel, and M. G. F. Sales. 2010. FIA potentiometric system based on periodate polymeric membrane sensors for the assessment of ascorbic acid in commercial drinks. Food Chem. 120 934-939. 

The multitransduction of signals was explored for the quantification of metals in solution. A polymeric membrane sensor was developed by incorporation of 5,10,15,20-tetra(ferrocenyl)porphyrin [248]. Simultaneous optical and potentiometric measurements made possible the detection of lead in the 2.7 x 10 to... 

Holler, L., I. Bedlechowicz, T.s. Vigassy, R.b.E. Gyurcsanyi, E. Bakker, and E. Pretsch. 2009. Limitations of current polarization for lowering the detection limit of potentiometric polymeric membrane sensors. Anal. Chem. 81 3592-3599. 

In potentiometric electrochemical devices (Fig. 13.7A), the sensors may be ion selective membranes or polymeric membranes (eg, Upid membranes or others), comprising a mixture of sensor additive chemical compounds, plasticizers and a suitable polymeric matrix, applied using appropriate techniques (eg, drop-by-drop) to a solid support (eg, acrylic body screen-printed) (Fig. 13.8). The type of sensors and relative... 

More recendy, two different types of nonglass pH electrodes have been described which have shown excellent pH-response behavior. In the neutral-carrier, ion-selective electrode type of potentiometric sensor, synthetic organic ionophores, selective for hydrogen ions, are immobilized in polymeric membranes (see Membrane technology) (9). These membranes are then used in more-or-less classical glass pH electrode configurations. 

Today, the term solid electrolyte or fast ionic conductor or, sometimes, superionic conductor is used to describe solid materials whose conductivity is wholly due to ionic displacement. Mixed conductors exhibit both ionic and electronic conductivity. Solid electrolytes range from hard, refractory materials, such as 8 mol% Y2C>3-stabilized Zr02(YSZ) or sodium fT-AbCb (NaAluOn), to soft proton-exchange polymeric membranes such as Du Pont s Nafion and include compounds that are stoichiometric (Agl), non-stoichiometric (sodium J3"-A12C>3) or doped (YSZ). The preparation, properties, and some applications of solid electrolytes have been discussed in a number of books2 5 and reviews.6,7 The main commercial application of solid electrolytes is in gas sensors.8,9 Another emerging application is in solid oxide fuel cells.4,5,1, n... 

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