Chemical sensor selectivity

Definition the electronic tongue is an analytical instrarment including an array of low-selective chemical sensors and appropriate pattern recognition tool, capable to recognize quantitative and qualitative compositions of simple and complex solutions . 

The development of highly selective chemical sensors for complex matrixes of medical, environmental, and industrial interest has been the object of greate research efforts in the last years. Recently, the use of artificial materials - molecularly imprinted polymers (MIPs) - with high recognition properties has been proposed for designing biomimetic sensors, but only a few sensor applications of MIPs based on electrosynythesized conductive polymers (MIEPs) have been reported [1-3]. 

R. Eugster, T. Rosatzin, B. Rusterholz, B. Aebersold, U. Pedrazza, D. Ruegg, A. Schmid, U.E. Spichiger, and W. Simon, Plasticizers for liquid polymeric membranes of ion-selective chemical sensors. Anal. Chim. Acta 289, 1-13 (1994). 

Puech, J.-L., Prida, A., and Isz, S. (2007). Quality assessment of oenological tannins utilising global selectivity chemical sensors array (electronic tongue). S. Afr. J. Enol. Vitic. 28(2), 101-106. 

An alternative to the Nicolsky-Eisenman equation to model this space is using an electronic tongue that consists of an array of nonspecific, poorly selective, chemical sensors with cross-sensitivity to different compounds in the solution, and an appropriate chemometric tool for the data processing. In our case, three ISEs and an ANN model is used. 

The wide variability of absorption and diffusional properties of chemical species in organic polymer films makes them useful as selective or complete permeation barriers (e.g., gas separation membranes and passivating layers [1,5,82]) and selective chemical sensor coatings [83]. For these applications, a method for rapidly and directly evaluating the solubility and diffusional properties in thin films is useful. Diffusional properties can be evaluated by monitoring the transient up-... 

The chemical sensors array devices (so called electronic tongues ) are defined in IUPAC Technical Report of Analytical Chemistry Division as an analytical instrument comprising an array of nonspecific, low selective chemical sensors with... 

One of the most important categories of ion selective chemical sensors is based on what are called liquid membranes. This term was flrst used in 196U to describe a matrix that is not water soluble it contains either anionic or cationic sites (liquid ion exchangers), which can selectivity facilitate the exchange of inorganic ions. In order to study the active carrier-mediated ion transport through these liquid membranes, a cell such as the one shown in Figure 3.4.4 has been employed. 

F. Goettmann, A. Moores, C. Boissiere, P. Le Floch, and C. Sanchez, A Selective Chemical Sensor Based on the Plasmonic Response of Phosphinine-stabilized Gold Nanoparticles Hosted on Periodically Organized Mesoporous Silica Thin Layers. Small, 2005,1, 636-639. 

Chemical sensors are important for industrial process control and environmental monitoring. They also find critical use in medical and defense applications. Two of the critical performance parameters of a sensor are selectivity and sensitivity. When integrated with an appropriate sensor platform (e.g., quartz crystal microbalance or electrochemical quartz crystal microbalance), a zeolite film can improve the selectivity and sensitivity of the sensor due to its ability to selectively adsorb a component out of a mixture. A large number of publications have appeared in this area, and an in-depth review on zeolite films for chemical sensor applications up to 1996 was provided as a section in a recent review by Bein. " Here, we highlight a recent development of selective chemical sensor based on continuous oriented zeolite films. 

Wong, H. E., Langmuir-Blodgett Film Technology in the Development of Selective Chemical Sensors, Ph. D. Thesis, University of Toronto, 1987. 

In the field of electrochemical sensors for liquids, there is the recent approach known as electronic tongue, which is inspired on the sense of taste. A widely accepted definition of electronic tongue (Holmberg et al. 2004) entails an analytical instrument comprising an array of non-specific, poorly selective, chemical sensors with crosssensitivity to different compounds in a solution, and an appropriate chemometric tool for data processing. 

Vlasov, Y., Legin, A.A. Non-selective chemical sensors in analytical chemistry from electronic nose to electronic tongue. Fresenius J. Anal. Chem. 361, 255-260 (1998)... 

The aim of using the ex situ techniques is to obtain a better control of the microstructure and a preferential orientation of the crystals in the membrane with a shortened crystallization time rendering highly selective and permeable membranes. Preferential orientation is needed, not only for separation purposes, when high fluxes are required, but also for size-selective chemical sensors (see Section 11.6.6.2). Due to the anisotropy in the pore geometry of the zeolite crystals, an orientation that shows the widest channels in the direction of the flux is... 

An electronic tongue is defined as a bio-mimicking sensor based analytical device consisting of an array of nonspecific/low selective, chemical sensors with considerable stability and cross-sensitivity to different compounds in solution, and an appropriate method for pattern recognition and/or multivariate caUbration of data processing [48]. 

Manipulation of the permeability of the SAM to selected redox molecules can be achieved through the inclusion of molecular gates [28-38] or changes in the charge density of the SAM via an ionizable moiety [39-43]. These manipulations are directed toward the fabrication of selective chemical sensors. 

---