Membrane polyvinyl chloride

Liquid membranes consist of an organic phase, which by its hydrophobic nature is relatively impermeable to ions. Originally organic solvents such as decanol were used in conjunction with a porous hydrophobic membrane. These have been replaced by plasticized polyvinyl chloride membranes which behave like liquids yet have improved mechanical properties Other polymers such as silicone, polyurethane and ururshi, a... 

In connection with the content of this section, dynamic features of ion transports through polyvinyl chloride membranes [27,28], ion-exchange resin membranes [29,30], or BLMs [31-36] have been discussed in the light of VCTTMs. For wide and pertinent applications of the VCTTM, however, further investigations have been required on the experimental and theoretical methods to analyze VCTTM quantitatively. 

An important advance in ion-selective electrodes (ISEs) and related systems was based on the concept of polymeric liquid membranes developed by Eisenman [122]. The principle of this approach was to incorporate an organic compound as the ionophore into a polyvinyl chloride membrane... 

Materials with selective binding or transport properties will have a major impact on sensor design and fabrication. Selectivity in either binding or transport can be exploited for a variety of measurement needs. This selectivity can be either intrinsic, that is, built into the chemical properties of the material, or coupled with selective carriers that allow a non-selective material to be converted into a selective one (see the section on recognition chemistry). An example of the latter is the use of valinomycin as a selective carrier in a polyvinyl chloride membrane to form a potentiometric potassium ion sensor. Advances in the fields of gas separation materials for air purification and membrane development for desalinization are contemporary examples illustrating the importance of selective materials. As these materials are identified, they can be exploited for the design of selective measurement schemes. 

A polyvinyl chloride membrane electrode for heroin based on an ion-pair complex with tetraphenylborate is described (328). The sensor shows a near-Nernstian response over the heroin concentration range 0.01 M to 0.1 mM, with good selectivity for heroin in the presence of a number of adultercuits and base compounds present in illicit heroin powders. A cocaine sensor proposed by Zeng (329) uses a cocaine picrylaminate membrane. The calibration curve is linear in the range 0.01 M to 10 iM, with a coefficient of variation of less than... 

First binding-protein biosensor immobilized concanavalin A in a polyvinyl chloride membrane on a platinum wire electrode to measure yeast mannan [11]... 

The use of piezoelectric crystals for measuring dissolved CO2 was investigated (22). Crystals were coated with didodecylamine (DDDA) or dioctadecylamine (DODA) and placed in a chamber separated from the sample solution by a Teflon membrane, a Polyvinyl chloride membrane, or a Fluoropore filter with polyethylene web backing. The DDDA was 33 times more sensitive to H2O vapor than to CO2. The membranes were not sufficient for a selective measurement of CO2, and a differential mode of measurement was used to circumvent H2O vapor interference. 

Hydrophilic microporous polyvinyl chloride membranes activated with GA or treated with polyvinyl imine (actiDisks) are produced by PMC Bioproducts. PVC membranes with embedded fibrous cellulose derivates or functionalized... 

Yildirin, A.E., Hilmioglu, N.D. and Tulbentci, S. 2001. Pervaporation separation of benzene/cyclo-hexane mixtures by (polyvinyl chloride) membranes. 24(3) 275-279. 

Ion-selective electrodes are used in potentiometric detectors. Early designs inserted micropipette electrodes into the outlet of the separation capillary. The capillary outlet was widened using etching to make placement easier and decrease the electric field at the electrode. As such it was foimd that electrical decoupling was unnecessary. More recent designs have used coated wire electrodes where a solid wire is coated with a polyvinyl chloride membrane. The electrode is placed 50pm from the outlet of the capillary. Coated wire electrodes are much less fragile and easier to position than micropipette electrodes. 

It has been shown that the crown ether 126a is a sensing and selective material for the construction of the strontium-PVC (polyvinyl chloride) membrane sensor (Zamani et al. 2009). It should also be pointed out that crown 126a-d and thia-crown ethers 126e-h appear prove to be reagents for the selective extraction of alkaline earth over alkali metal ions with 2.7 (Mg Na extraction ratio) for the crown ether 126b, whereas this ratio for the thia-crown ether 126f is 8.0 (Ca rK extraction ratio) (Bakavoli et al. 2010). 

For drugs, liquid and polyvinyl chloride membrane electrodes which are sensitive and selective for atropine have been described. They are based on the inclusion of an atropine-reineckate ion-pair complex in the PVC matrix . ... 

In this part, different potentiometric ion-selective electrodes for the determination of surfactants will be discussed including liquid membrane electrodes, coti-ventional polyvinyl chloride membrane electrodes (PVC), solid crmtact electrodes, carbon paste electrodes (CPEs), and more recently disposable screen-printed electrodes (SPEs). 

An automated electronic tongue consisting of an array of potentiometric sensors and an artificial neural network (ANN) was developed to resolve mixtures of anionic surfactants. The sensor array was formed by five different flow-through sensors for anionic surfactants, based on polyvinyl chloride membranes having cross-sensitivity features. 

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