Sensors recognition

Binding of the analyte to the MIP is detected by the transducer and this results in an output signal. Typically, the system can be calibrated to provide quantitative information. MIPs have been used as sensor recognition elements for a variety of analytes using transduction methodologies based on... 

Other simulation experiments performed in our laboratory include design of MIP adsorbents for solid-phase extraction of atrazine [77], DDT, lindane, aflatoxin Bl, ochratoxin A, and tylosin (unpublished data) and the development of assay/ sensor recognition elements for biotin (unpublished data) and creatinine [78]. In all these cases, molecular modeling proved to be a useful tool for MIP design. It would... 

Micromonoliths used as sensor recognition elements provide a quick and easy fabrication scheme. One limitation to these monolith sensors was their capacity. The capacity of rod polymers was found to be very low and lower than LC columns packed with MIP particles. However, their ability to separate templates such as chloramphenicol from structurally similar analogues has been shown to be slightly better [47]. This may be an indication that while the number of viable imprinted sites is less, they are of similar selectivity. 

Many complex systems have been spread on liquid interfaces for a variety of reasons. We begin this chapter with a discussion of the behavior of synthetic polymers at the liquid-air interface. Most of these systems are linear macromolecules however, rigid-rod polymers and more complex structures are of interest for potential optoelectronic applications. Biological macromolecules are spread at the liquid-vapor interface to fabricate sensors and other biomedical devices. In addition, the study of proteins at the air-water interface yields important information on enzymatic recognition, and membrane protein behavior. We touch on other biological systems, namely, phospholipids and cholesterol monolayers. These systems are so widely and routinely studied these days that they were also mentioned in some detail in Chapter IV. The closely related matter of bilayers and vesicles is also briefly addressed. 

There are three advantages to study molecular recognition on surfaces and interfaces (monolayers, films, membranes or soHds) (175) (/) rigid receptor sites can be designed (2) the synthetic chemistry may be simplified (J) the surface can be attached to transducers which makes analysis easier and may transform the molecular recognition interface to a chemical sensor. And, which is also a typical fact, this kind of molecular recognition involves outside directed interaction sites, ie, exo-receptor function (9) (see Fig. 5b). 

In the field of chemical sensors, the revolution in software and inexpensive hardware means that not only nonlinear chemical responses can be tolerated, but incomplete selectivity to a variety of chemical species can also be handled. Arrays of imperfectly selective sensors can be used in conjunction with pattern recognition algorithms to sort out classes of chemical compounds and thek concentrations when the latter are mixed together. 

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]. 

The mechanism of recognition of most supramolecular entities (such as abiotic receptors) is the formation of several hydrogen bonds. Since heterocyclic tautomers possess both strong HBA and HBD properties (see Sections III,G, V,D,2, and VI,G), they are often used for this purpose. For instance, the hydrogen bond network formed by 5,5 -linked bis(2-pyridones) has been used by Dickert to obtain sensors (96BBG1312). 

The key recognitive skill required to carry out the above tasks is the formation of a mental model of the process operations that fits the current facts about the process and enables the operators to correctly assess process behavior and predict the effects of possible control actions. Correct mental models of process operations have allowed operators to overcome the weakness of lost sensors and conflicting trends, even under the pressure of an emergency (Dvorak, 1987), whereas most of the operational mishandlings are due to an erroneous perception as to what is going on in the process (O Shima, 1983). 

---