Sabu Thomas, Yves Grohens, Nandakumar Kalarikkal, Oluwatobi Samuel Oluwafemi, Praveen K. M. (Eds): Nanotechnology-Driven Engineered Materials—New Insights

Recent Trends in Solid-Phase Extraction for Environmental, Food and Biological Sample Preparation

Somenath Mitra, Pradyot Patnaik and Barbara B. Kebbekus: Environmental Chemical Analysis, 2nd Edn

Congress, Conferences, and Workshops

Advances in Cellulose-Based Sorbents for Extraction of Pollutants in Environmental Samples Abstract The effective extraction and detection of pollutants in the environment have been important issues in analytical science. Cellulosic materials, composed of both functionalized and composited components, have been recently identified as promising solid-phase extraction adsorbents for various applications. Due to their alluring properties such as renewability, biodegradability, biocompatibility, high strength and stiffness and easy modification, this unique class of materials exhibits excellent extraction and enrichment performance for numerous target analytes. Herein, we review recent significant advances in solid-phase extraction using cellulosic sorbents for organic and inorganic pollutants in environmental matrices. The development of new cellulose-based sorbents and related solid-phase extraction (SPE) patterns, including cartridge SPE (c-SPE), disk SPE, dispersive SPE, magnetic SPE, molecularly imprinted SPE, on-line SPE, SPE spectroscopy/spectrometry and thin film microextraction (TFME), were discussed in this review.

Simultaneous Determination and Enrichment of β -Sitosterol From Edible Oil Samples Using Poly(NMA-ST- co -TAIC- co -EDMA) Monolith as Sorbent with On-line SPE-HPLC Abstract A poly(NMA-ST-co-TAIC-EDMA) monolithic column was prepared by redox initiation method using N-methylolacrylamide (NMA) and styrene (ST) as co-monomers. The composite monolith was characterized by scanning electron microscopy (SEM) and nitrogen adsorption–desorption isotherm and was used as a solid phase extraction (SPE) absorbent for enrichment of β-sitosterol by high performance liquid chromatography (HPLC). Under the optimum conditions for extraction and determination, the calibration equation was y = 1.02247x + 0.1766; the linear range was 0.015–0.75 mg mL−1 and the linear regression coefficient was 0.998. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.006 mg mL−1 and 0.02 mg mL−1, respectively. The spiked recoveries of β-sitosterol in edible oil samples were 83.60–103.88%; precisions for intra-day and inter-day assays presented as relative standard deviations were less than 6.0% and 6.2%, respectively. The enrichment factor of β-sitosterol was 60 and the results showed that the monolithic column had high selectivity and good permeability as an on-line SPE absorbent for the enrichment and determination of β-sitosterol from edible oils.

Humic Acids Pyrolyzed onto Silica Microparticles for Solid-Phase Extraction of Benzotriazoles and Benzothiazoles from Environmental Waters Abstract This work focuses on the extraction and determination of contaminants of environmental concern belonging to the classes of benzotriazoles and benzothiazoles from tap and raw river water samples. The sorbent, recently proposed by this research group, prepared by pyrolysis of humic acids (HAs) onto silica microparticles (HA-C@silica), was tested for fixed-bed SPE of benzotriazole and benzothiazole compounds by modulating its sorption affinity through the carbon loading. This was successfully increased from 10 to 20 wt% HAs and the obtained material, characterized by different techniques, provided quantitative adsorption at the sample native pH (7.5–8), for 50–250 mL samples spiked with each compound at the micrograms per litre levels. After extraction, the analytes were simultaneously desorbed by 4 mL methanol, even more reducible to small volume before HPLC–HESI-MS/MS analysis. Recovery was satisfactory for all compounds, ranging from 70 to 114%, with RSD values ≤ 16% (n = 3). The developed procedure allows quantitation of benzotriazoles at concentrations far below the environmental trigger limits. HA-C@silica turned out to be appealing in comparison with the commercial sorbents in terms of cost, recovery and pre-concentration for determination of such pollutants in actual surface waters. Good reproducibility was observed on independent HA-C@silica preparations.

Metal–Organic Frameworks in Solid-Phase Extraction Procedures for Environmental and Food Analyses Abstract Environmental and food analysis usually require the use of sample preparation steps, with significant utilization of solid-phase extraction techniques. This review article covers recent trends in the use of metal–organic frameworks (MOFs) as novel sorbents, with particular emphasize on miniaturized methods to follow green analytical chemistry principles. Thus, the use of MOFs in miniaturized solid-phase extraction (µSPE), performed in static off-line and on-line modes, and solid-phase microextraction (SPME), including the on-line procedures of in-tube and on-disk approaches, will be described with particular emphasis on the specific applications.

Recent Developments in Selective Materials for Solid Phase Extraction Abstract The success of any analytical method depends largely on the sample preparation technique which is usually employed for the extraction and pre-concentration of the target analyte from a sample matrix. In this context, solid-phase extraction has been greatly explored by various researchers in many scientific fields including environmental analysis of pollutants, as well as analysis of food and biological samples. One of the solid-phase extraction drawbacks observed over the years is its inability to selectively extract the target analytes from the sample matrix, which could have a consequence of prolonging the analysis times and have negative effect on the analytical data. In this paper, recent trends starting from the work published in 2014–2018 in selective solid-phase extraction are critically reviewed while interesting studies prior to 2014 are mentioned. Solid-phase extraction sorbents that have been revealed in greater extent in literature to offer better selectivity are molecularly imprinted polymers and nano sorbents. Other sorbents reviewed in this work include composite materials which are sometimes designed for improving the adsorption capacity as well as selectivity. Mixed-mode ion-exchange polymers categorized as class selective sorbents have also been reviewed and recent applications are cited. Moreover, a broad discussion on miniaturization, new inventions and future of selective solid-phase extraction utilizing different sorbents in various sample matrices is outlined. Graphical Abstract

Recent Applications of Magnetic Solid-phase Extraction for Sample Preparation Abstract This minireview is dedicated to the discussion of analytical methods based on magnetic solid-phase extraction for the investigation of different analyte classes in complex matrices. Magnetic solid-phase extraction represents one of the most exploited approaches for sample preparation, which benefits from the development of new materials and from the coupling with other purification and clean-up strategies. New materials are continuously described for the isolation and enrichment of a variety of compounds, from small molecules to biologic macromolecules. Such magnetic materials developed for magnetic solid-phase extraction are discussed in this minireview, spanning across different types of materials, from the more traditional magnetic nanoparticles functionalized with polymers, to molecularly imprinted polymers, but also graphene, carbon nanotubes, graphitized carbon black, metal organic frameworks, covalent organic frameworks, composite materials, biopolymers (polydopamine, chitosan), materials from wastes and natural products and the newly introduced knitting aromatic polymers. The magnetic solid-phase extraction methods are collected from the recent literature and organized in sections based on the target analyte classes, which include drugs, endocrine-disrupting compounds, pesticides, polycyclic aromatic hydrocarbons, metals, toxins, peptides, proteins, metabolites and a final chapter dedicated to applications to other common pollutants, contaminants and multiresidue methods. A selection of recent applications and variations of the traditional magnetic solid-phase extraction protocols is discussed for food, environmental and biologic matrices. Finally, the compliance of magnetic solid-phase extraction with the principles of green analytical chemistry is also briefly discussed, with recent examples, indicating the use of waste or sustainable materials, development of green material preparations and reduction of organic solvents as the main strategies for future development of environmentally friendly magnetic solid-phase extraction methods. Graphical Abstract