Recent Advances in Microextraction Technology for Analytical Sample Preparation

A special issue of Separations (ISSN 2297-8739). This special issue belongs to the section "Purification Technology".

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 4526

Special Issue Editors

Department of Agriculture, Environmental and Food Sciences, University of Molise, Campobasso via De Sanctis, I-86100 Campobasso, Italy
Interests: separation sciences; GC-MS; SPE; microextraction; analytical chemistry
Department of Agricultural, Environmental and Food Sciences (DiAAA), University of Molise, Via F. De Sanctis, I-86100 Campobasso, Italy
Interests: phthalates; bisphenol-A; plasticizers; microplastics; environment; human health; endocrine disruptors
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Special Issue Information

Dear Colleagues,

“Microextraction is defined as an extraction technique where the volume of the extracting phase is very small in relation to the volume of the sample, and extraction of analytes is not exhaustive”: this definition was coined by Lord and Pawliszyn in 2000. Twenty years later, this definition is still valid, and extraction techniques play a fundamental role in the development of an analytical method. Today, extraction procedures range from classic procedures involving liquid-liquid extraction to new methodologies involving molecularly imprinted polymers. This Special Issue aims to showcase the state of the art of classic microextractions and give an overview of new advances in microextraction technology. Contributions ranging from theory to instrumentation and applications in different fields (e.g., food, environment, forensic, pharmaceutical, clinic) are welcome.

Prof. Dr. Mario Vincenzo Russo
Prof. Dr. Pasquale Avino
Guest Editors

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Keywords

  • theory
  • extraction
  • solvent microextraction
  • solid-phase extraction / solid-phase microextraction (SPE / SPME)
  • drop-to-drop microextraction / dispersive liquid-liquid microextraction (DDME / DLLME)
  • microextraction in a packed syringe (MEPS)
  • single-drop microextraction (SDME)
  • coupling
  • nanomaterials
  • green analytical chemistry

Published Papers (3 papers)

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Research

10 pages, 1871 KiB  
Article
Determination of Ethylene Glycol Dinitrate in Environmental and Forensic Water Samples Using Microextraction by Packed Sorbent Followed by Gas Chromatography
by Svetlana Hrouzková, Tamara Pócsová, Tímea Lelkesová and Pavol Ulbrich
Separations 2023, 10(4), 227; https://doi.org/10.3390/separations10040227 - 25 Mar 2023
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Abstract
Ethylene glycol dinitrate (EGDN) is a liquid nitrate ester, a secondary explosive. In the past, it was used as an explosive ingredient in dynamite along with nitroglycerine. Due to its various applications, the reliable detection of EGDN in the environment is a key [...] Read more.
Ethylene glycol dinitrate (EGDN) is a liquid nitrate ester, a secondary explosive. In the past, it was used as an explosive ingredient in dynamite along with nitroglycerine. Due to its various applications, the reliable detection of EGDN in the environment is a key issue for both forensic and environmental applications. In these areas, sensitive and reliable methods for determining the concentration of nitro compounds are needed. Microextraction by packed sorbent (MEPS) is an innovative approach to green technology in the sample preparation field. Compared to conventional solid-phase extraction (SPE), MEPS uses a smaller sample volume and can be easily combined with various chromatographic techniques. An important benefit is the reduction of sorbent amount and up to 100-times repeatable use compared to disposable SPE columns, thus reducing the costs of analysis as well as waste production. Optimal extraction parameters for isolating EGDN from water, e.g., 30 µL of toluene as extraction agent, working in one cycle and in draw/discard mode, were selected. Method validation was performed, obtaining a limit of detection and a limit of quantification of 0.45 pg/μL and 1.34 pg/μL, respectively. Accuracy in terms of recovery rates was evaluated over a wide concentration range, obtaining values from 83.7 to 90.0%. The satisfactory linearity expressed by the coefficient of determination was 0.9914. A matrix factor of −9.3% indicates a weak matrix effect. The application to real environmental water samples and a forensic post-blast wash water sample was realized. EGDN detection in the post-blast samples provides valuable information for forensic technicians. Full article
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15 pages, 5263 KiB  
Article
Preparation of Fe3O4-Reduced Graphene-Activated Carbon from Wastepaper in the Dispersive Solid-Phase Extraction and UHPLC-PDA Determination of Antibiotics in Human Plasma
by Pantaleone Bruni, Pasquale Avino, Vincenzo Ferrone, Serena Pilato, Nadia Barbacane, Valentino Canale, Giuseppe Carlucci and Stefania Ferrari
Separations 2023, 10(2), 115; https://doi.org/10.3390/separations10020115 - 07 Feb 2023
Cited by 2 | Viewed by 1301
Abstract
In this work, a sorbent was prepared from wastepaper samples enriched with iron oxide particles and graphene oxide and used in the solid phase extraction of antibiotics. The precursor underwent a carbothermal reduction to promote the formation of paramagnetic phases useful for the [...] Read more.
In this work, a sorbent was prepared from wastepaper samples enriched with iron oxide particles and graphene oxide and used in the solid phase extraction of antibiotics. The precursor underwent a carbothermal reduction to promote the formation of paramagnetic phases useful for the recovery of the sorbent during the analysis, and to disperse and fix graphene and the iron oxide in a durable way throughout the cellulose structure. Characterizations were carried out to evaluate the composition (Raman, XRD and EDX) and the morphological structure (SEM) of the material. A UHPLC-PDA method was developed for the simultaneous determination of antibiotics from different drug families (carbapenems, fluoroquinolones, β-lactams) using a 120 SB-C 18 poroshell column (50 × 2.1 mm I.D., 2.7 um particle size) and a mobile phase consisting of 10 mM acetate buffer at pH 5 (Line A) and acetonitrile (Line B) both containing 0.1% of triethylamine. A gradient elution was used for the separation of the analytes, while for the quantitative analysis each analyte was determined at its maximum wavelength. Several experiments were carried out to evaluate the influence of different parameters involving the dispersive magnetic solid phase extraction of these analytes. Samples were extracted using 25 mg of sorbent at pH 5 and desorbed in 5 min using methanol. We report herein on some of the outstanding advantages of using carbon-based sorbent, such as lower toxicity, scalability, improved absorption capacity, target selectivity and stability in acidic medium. Moreover, from the results obtained it is evident that, despite the use of some recycled materials, the performances obtained were comparable or even superior to the methods reported in the literature. Full article
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14 pages, 1677 KiB  
Article
Multiple Heart-Cutting Two-Dimensional HPLC-UV Achiral–Chiral Analysis of Branched-Chain Amino Acids in Food Supplements under Environmentally Friendly Conditions
by Ina Varfaj, Simone Moretti, Federica Ianni, Carolina Barola, Ghaid W. A. Abualzulof, Andrea Carotti, Lina Cossignani, Roberta Galarini and Roccaldo Sardella
Separations 2023, 10(1), 45; https://doi.org/10.3390/separations10010045 - 11 Jan 2023
Cited by 4 | Viewed by 1961
Abstract
A multiple heart-cutting (mLC-LC) two-dimensional HPLC-UV achiral–chiral method for the direct analysis of branched-chain amino acids (BCAAs) in food supplements under environmentally friendly conditions was developed to cope with the very well-known limited chemoselectivity of chromatographic media for enantioselective analysis. Both achiral and [...] Read more.
A multiple heart-cutting (mLC-LC) two-dimensional HPLC-UV achiral–chiral method for the direct analysis of branched-chain amino acids (BCAAs) in food supplements under environmentally friendly conditions was developed to cope with the very well-known limited chemoselectivity of chromatographic media for enantioselective analysis. Both achiral and chiral methods were developed in compliance with the main principles of green chromatography. The achiral analysis was performed isocratically with an optimized ion-pair reversed-phase (IP-RP) method based on a water/EtOH (95:5, v/v) mobile phase containing heptafluorobutyric acid (7 mM) as the IP agent. The achiral method was characterized by a very appreciable performance and was validated before the analysis of the real sample. High recovery values for all compounds (from 97% to 101%) were found in the interday evaluation. Additionally, low RSD% values in the long-term period were measured, in the range between 1.1% and 4.8%. Still, an LOQ value of 0.06 mg/mL was established for all compounds. The quantitative analysis of a commercial food supplement revealed that BCAAs were present in amounts very close to those declared by the producer. The enantioselective analysis was carried out through the application of the chiral ligand-exchange chromatography (CLEC) approach, using O-benzyl-(S)-serine ((S)-OBS, 0.5 mM) as the chiral selector and Cu(II) nitrate (0.25 mM) as the metal source in the eluent. Resolution and separation factor values up to 2.31 and 1.43, respectively, were obtained. The two chromatographic systems were connected through a six-port switching valve, and the developed two-dimensional mLC-LC method confirmed the absence of D-enantiomers of BCAAs in the food supplement, as reported in the manufacturer’s label. Full article
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