Solid-phase extraction of organic compounds: A critical review (Part II)

Solid-phase extraction (SPE) is the most widely used method for the extraction, changing of solvents, clean-up, concentration and fractionation of organic compounds from several samples. Here, we attempt to resolve the debates surrounding the suitability of sorbents for the extraction of several compounds, conditioning, washing and elution protocols, as well as the recoveries achieved by each SPE protocol. The lack of systematization and homogenization limits the efficient implementation of reliable SPE procedures. This part focuses on the advantages and disadvantages of SPE versus liquid-liquid extraction (LLE), controversies and contradictions found in the literature with respect to the selection of sorbents, optimization of conditioning and elution protocols and recoveries by SPE. Moreover, it reveals the lack of selectivity of most sorbents and SPE protocols. It is divided into the following sections: applications of SPE, fractionation by SPE, outlook and conclusions. (C) 2015 Elsevier B.V. All rights reserved.