Titanium-dioxide nanotubes as sorbents in (micro)extraction techniques

•We summarize the use of titanium-dioxide nanotubes (TDNTs) as sorbents.•We describe the main properties and the ways of synthesizing TDNTs.•We explain the main applications of TDNTs in SPE and SPME.•We outline future trends in the use of TDNTs as sorbents in (micro)extraction.

Titanium-dioxide nanotubes (TDNTs) are elongated nanomaterials with a large specific surface area and notable features, such as inertness, chemical and thermal stability. This overview focuses on the use of TDNTs as sorbents in sample preparation. After a brief introduction to their properties and structure, we describe the main routes of synthesis for the laboratory production of TDNTs. These routes, which comprise electrochemical, chemical-template and hydrothermal approaches, mark the ultimate application of this nanomaterial. Finally, we present the usefulness of TDNTs in solid-phase extraction (SPE), micro-SPE and solid-phase microextraction contexts on the basis of the published literature.