Micro-solid-phase extraction

The direct determination of compounds of interest is challenging and, in the majority of cases, impossible. This fact is related to the low concentration of analytes as well as the presence of possible interferences in many sample types. Hence, there is a need for a sample preparation step before the final analysis. To this end, great attention has been devoted to designing and using miniaturized extraction techniques (METs) as alternatives to conventional procedures. METs can address the main drawbacks of conventional sample preparation methods. These include excessive consumption of organic solvents or reagents, need for multiple operations or steps, inconvenience or difficulty of automation, etc. Amongst the METs, micro-solid-phase extraction (µ-SPE) has garnered much attention thanks to its demonstrable advantages. In µ-SPE the consumption of materials (solvents, reagents, etc.) is reduced. Also, sorbents with small (e.g., micro- and nanoscale) dimensions are utilized. Moreover, the procedure involves use of miniaturized extraction devices and apparatus, etc. The contents of this chapter are focused on the fundamentals, configurations and applications of µ-SPE. Novel materials that have been used as sorbents in µ-SPE are investigated and discussed. Finally, current trends and prospects concerning the application of the technique are assessed.