Recent advances in combining microextraction techniques for sample pre-treatment

Sorbent and solvent microextraction techniques, mainly solid-phase microextraction, stir-bar sorptive extraction, single-drop microextraction, dispersive liquid-liquid microextraction, and hollow-fiber liquid-phase microextraction, are well-established, environment-friendly procedures for treating a wide range of samples when isolating organic and inorganic targets. Recently, microextraction techniques combined with other sample pre-treatments were shown to be excellent approaches for improving target isolation, and, thus, for enhancing the quality of the whole analysis. This review therefore deals with recent advances when coupling several microextraction techniques as sample pre-treatment methods for liquid and solid environmental and biological materials. This review includes an updated overview on combined microextraction techniques (design and operational requirements), the advantages and the disadvantages of current developments, and future prospects.