Authors: Francisco Pena-Pereira
Book: Miniaturization in sample preparation, Ed. De Gruyter Open, pp. 1-28, 2014
Nowadays, the term miniaturization is applied to a wide spectrum of knowledge areas, including, among others, engineering, physics, medicine, materials science, com-puter science and chemistry. A search on the ISI Web of Knowledge provided approxi-mately 42000 results by entering the term miniaturization, from which around 5200 results are devoted to chemistry. The number of publications concerning the min-iaturization of chemical systems has experienced an important increase in the last two decades, as has the number of citations received by these publications, as shown in Figure 1.1. In accordance with the ISI Web of Knowledge, they currently receive around 12000 citations per year. Nevertheless, this is only the tip of the iceberg since the number of publications devoted to the development and application of miniatur-ized analytical systems (but not referring to miniaturization in the title or abstract sections) are not included. In the broadest sense of the word, miniaturization can be defined as the produc-tion of novel systems that are substantially reduced in size in comparison with con-ventional systems. In analytical chemistry, the term miniaturization does not refer solely to the scaling-down of analytical instrumentation, apparatus and devices since it is also applicable when the components (including chemicals and solvents) needed to perform analytical operations are employed on a greatly reduced scale. In fact, size reduction is not the main driving force when shrinking analytical systems, as can be deduced from section 1.2. It is worth noting that the term miniaturization has been mainly employed in the analytical chemistry literature to refer to the micro-total anal-ysis systems (µ-TAS) and lab-on-a-chip (LOC) devices. Even though they represent the highest degree of downsizing, the concept of miniaturization should be observed from a broader, non-exclusive perspective since this concept includes the advances achieved in every single step of the analytical process. A recent trend in analytical chemistry is a progression towards the miniaturiza-tion of analytical systems. Different steps of the analytical process, including sample preparation, analytical separation and detection have been subjected to miniaturiza-tion, automation and portability. In addition, the integration of different analytical steps has allowed the development of fully miniaturized systems.