Cantilever Array for Chemical Sensing: Development of a Moisture-Independent Sensor with Possible Application in Explosive Detection

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Chapter 2 Fundamentals of Chemical Detection 2.1 Chemical Sensing: History and Definition In instrumental chemical analysis, thanks to the advent of microelectronics, a general trend towards miniaturization can be observed. In around 1950, many analytical instruments were so big that they occupied entire laboratories. In the final decades of the last century, a strong tendency towards automation appeared in chemical analysis. Big central laboratory complexes were established. One reason for centralizing the resources is the high cost of modern instruments. However, at a certain point, it became obvious that not every problem could be solved smoothly in this way. In many cases, it was difficult or impossible to transport samples long distances without decomposition. Commonly, it proved to be much more simple to bring the instrument to the sample rather than the sample to the instrument. Mobile techniques of chemical analysis attracted increasing interest. Analysts started to look for small, transportable analytical probes which could be stuck smoothly into a sample. After the advent of Micro-Electro-Mechanical Systems (MEMS) another strong trend towards miniaturization of measuring instruments in chemical analysis was observed. In the most general form, MEMS consist of mechanical microstructures, microsensors, mi- croactuators, and microelectronics, all integrated onto the same silicon chip. There exist specific reasons to minimize the dimensions of analytical instruments. Very small instruments are expected to work faster than big ones, since small-scale chemical reactions generally happen faster and the volume of reagents involved is small. Moreover it is much easier to carry out automation with smaller instruments and a higher degree of automation improves the immunity of the instrument against interference, and can be operated by less qualified personnel. The term sensor started to gain currency during the 1970s [13] . This development was caused by technological developments which are part of a technical revolution that contin- ues to this day. Rapid adavances in microelecronics made available technical intelligence. Machines became more “intelligent” and more autonomous. There arose a demand for 5

Anteprima della Tesi di Stefano Fissolo

Anteprima della tesi: Cantilever Array for Chemical Sensing: Development of a Moisture-Independent Sensor with Possible Application in Explosive Detection, Pagina 5

Laurea liv.II (specialistica)

Facoltà: Ingegneria

Autore: Stefano Fissolo Contatta »

Composta da 104 pagine.

 

Questa tesi ha raggiunto 209 click dal 20/10/2008.

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