Carbon Nanotubes in Sample Preparation

The discovery and implementation of new materials in sample preparation have a significant impact on the development of new analytical methods and often on the instrumentation used in chemical analysis. In recent years, nanostructured materials of different chemical composition, such as nanoparticles, nanowires or nanotubes have received increasing attention. Their introduction in almost every stage of chemical analysis has constituted a significant milestone in modern analytical chemistry. Carbon nanotubes (CNTs) are allotropes of carbon that can be obtained as a single-walled (SWCNTs), or multi-walled (MWCNTs) material with a cylindrical nanostructure. Since their discovery in 1991, they have attracted great attention, because of their unique properties, which make them potentially useful in a wide range of scientific fields, from electronics to medicinal chemistry. In analytical chemistry, CNTs can be used as chromatographic solid phase material, and can therefore be directly involved in any step of chemical analysis. More specifically, due to the porous graphite structure of CNTs, they can be used as sorbents in sample preparation techniques, such as Solid Phase Extraction or Solid Phase Microextraction, for the cleaning up and the pre-concentration of a great variety of analytes in different matrices. Many applications can be found in literature regarding the analysis of phenolic compounds, pesticides, pharmaceuticals, inorganic ions, organometallic compounds, etc. in food, in environmental samples, or in biofluids with the use of CNTs. The objective of this review is to summarize the applications of carbon nanotubes in sample preparation over the past decade.