Extraction of Metal Ions with Metal–Organic Frameworks

Abstract

Metal–organic frameworks (MOFs) are crystalline porous materials composed of metal ions or clusters coordinated with organic linkers. Due to their extraordinary properties such as high porosity with homogeneous and tunable in size pores/cages, as well as high thermal and chemical stability, MOFs have gained attention in diverse analytical applications. MOFs have been coupled with a wide variety of extraction techniques including solid-phase extraction (SPE), dispersive solid-phase extraction (d-SPE), and magnetic solid-phase extraction (MSPE) for the extraction and preconcentration of metal ions from complex matrices. The low concentration levels of metal ions in real samples including food samples, environmental samples, and biological samples, as well as the increased number of potentially interfering ions, make the determination of trace levels of metal ions still challenging. A wide variety of MOF materials have been employed for the extraction of metals from sample matrices prior to their determination with spectrometric techniques.

Bioanalytical HPLC Applications of In-Tube Solid Phase Microextraction: A Two-Decade Overview

“…MOFs exhibit a plethora of extraordinary properties, such as high surface area, tunability of pore size and functionality, luminosity, flexibility of their structure, and thermal stability. MOFs have been evaluated for their applications in analytical chemistry, both as sorbents in sample preparation and as stationary phases in high performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE) [109][110][111]. Zeolitic imidazolate frameworks (ZIFs) are a subclass of MOFs that combine the benefits of zeolites and MOFs.…”

“…Zeolitic imidazolate frameworks (ZIFs) are a subclass of MOFs that combine the benefits of zeolites and MOFs. ZIFs are composed of Zn(II) or Co(II) metal ions and imidazolate and its derivatives as organic linkers [110].…”

“…Those materials combine the benefits of MOFs and monoliths providing efficient coatings with specific surface area, high extraction efficiency and low-backpressure that can be easily prepared [75][76][77][78]. However, since many MOFs exhibit low stability in aqueous solutions, proper selection of the MOF should be performed [110].…”

Recent Applications of Magnetic Nanoparticles in Food Analysis

“…MOFs are in general composed by a metal ion or a metal cluster centre, self-assembled with a 3D organic ligands framework. They have been extensively used in food analysis in the last decades due to their pore design and functionalisation flexibility and high surface area, as shown in different reviews dealing with the topic [31,32]. Their combination with m-NPs to form the so-called magnetic MOFs (m-MOFs) or magnetic frameworks composites (m-FCs) provides them in general with a better stability than MOFs alone, as well as superparamagnetism, rapid and easy adsorption/desorption steps and high recycling rates.…”

New Efficient Adsorbent Materials for the Removal of Cd(II) from Aqueous Solutions

“…The most economical, feasible and selective method for heavy metal removal from aqueous solutions is the adsorption technique [16,17]. Therefore, researchers are focused on the development of new and more efficient adsorbent materials ranging from natural substances to highly selective synthetic systems to be used as hazardous metal adsorbents [2,[18][19][20][21][22][23]. Heavy metal ions, even at small concentrations, are extremely toxic to alive organisms, because they are non-biodegradable, and they tend to accumulate in the environment.…”