Graphene oxide applied at dispersive Solid Phase Microextraction (DSPME) to metals preconcentration in liquid samples

Abstract

Separation and preconcentration procedures are often required for the elimination of interferents, increased sensitivity and improvement detection limits. Such procedures include liquid phase extraction, solid phase extraction, co-precipitation and precipitation. The conventional solid-phase extraction (batch) has many applications in the determination of analytes of various types, in low concentrations, and in complex matrices such as environmental, food and biological. The main disadvantages of this type of extraction are the high reagent consumption, the sample and the low analytical frequency. A proposal for the simplification of the process of extraction and reduction of reagent and sample consumption is the dispersive microextraction solid phase (D-m-SPE). This type of microextraction originated from dispersive liquid-liquid microextraction (DLLME) and is based on the efficient introduction of a reduced amount of solid phase to a liquid sample. Graphene oxide, due to its large surface area, among other desirable characteristics, has found application in the extraction of metals. The great majority of works reported in the literature uses graphene oxide in methods for column or batch extraction. The present project has as main objective the use of D-m-SPE in the development of an analytical method for the determination of metals such as Ca, Al, Cu, Fe, Mn, Zn, Ti, Cd, Ni and Cr, present in liquid samples. Enjoying all the advantages of D-m-SPE has as specific objective: (i) to propose the use of graphene oxide as a solid phase and (ii) to explore the advantages of D-m-SPE combined with the detection of metals by analytical techniques that allow the direct analysis of solids.