Neoteric solvents: Applications in matrix solid-phase dispersion extraction

Abstract

In recent years, green chemistry has focused on the search for green solvents to replace the toxic organic solvents traditionally used in sample preparation. Ionic liquids (ILs) and deep eutectic solvents (DESs), which belong to neoteric liquids, are environmentally friendly solvents widely used for the extraction and subsequent determination of bioactive molecules and contaminants. ILs are semi-organic molten salts at temperature below 100 °C, composed by organic cations and organic or inorganic anions. DESs are a greener evolution of ionic liquids, consisting of a quaternary ammonium salt that acts as a hydrogen bond acceptor molecule and organic acids, sugars, amines, or polyalcohols that can be used as hydrogen bond donor molecules. DES components, when combined in a specific molar ratio, form an eutectic mixture that is liquid at room temperature. Both DESs and ILs have been widely applied in several extraction procedures, including matrix solid-phase dispersion (MSPD) extraction. MSPD is an extraction technique based on a homogenization phase between a solid sample and a solid dispersing material that has the function of breaking the sample, increasing analytes extraction yield. Three possible uses of neoteric solvents in MSPD extraction were investigated: (i) as extraction solvents to replace traditional organic solvents; (ii) as an adjuvant of MSPD extraction, to be added to the sample and dispersing material during the homogenization step; (iii) as an element to create innovative and highly selective dispersing materials. This review aims to describe and discuss in detail the use of neoteric solvents in the MSPD process in their various applications.