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A device comprising a zirconium-based metal–organic framework (MOF) mixed-matrix membrane (MMM) framed in a plastic holder has been used to monitor the content of personal care products (PCPs) in cosmetic samples. Seven different devices containing the porous frameworks UiO-66, UiO-66-COOH, UiO-67, DUT-52, DUT-67, MOF-801, and MOF-808 in polyvinylidene fluoride (PVDF) membranes were studied. Optimized membranes reach high adsorption capacities of PCPs, up to 12.5 mg·g–1 benzophenone in a 3.0 mg·L–1 sample. The MMM adsorption kinetics, uptake measurements, and isotherm studies were carried out with aqueous standard solutions of PCPs to ensure complete characterization of the performance. The studies demonstrate the high applicability and selectivity of the composites prepared, highlighting the performance of PVDF/DUT-52 MMM that poses uptakes up to 78% for those PCPs with higher affinity while observing detection limits for the entire method down to 0.03 μg·L–1. The PVDF/DUT-52 device allowed the detection of parabens and benzophenones in the samples, with PCPs found at concentrations of 1.9–24 mg·L–1.

Magnetic ionic liquids (MILs) are materials of special interest in analytical chemistry and, particularly, in analytical microextraction. These solvents possess several of the properties derived from their inherent nature of ionic liquids, combined with their magnetism, that permits their manipulation with an external magnetic field. This feature allows for performing typical steps of the microextraction procedure in a simpler manner with the aid of a strong magnet. Although there are several important reviews summarizing the most innovative advances in this field, there is a gap of information, as they do not provide useful details and tips related to the experimental set up of these procedures. This tutorial review fills this gap by providing a guide for the proper handling of MILs, their manipulation with magnets, and their proper hyphenation with the most used analytical techniques. Attention is paid to dispersive liquid-liquid microextraction, stir-bar dispersive liquid microextraction, aqueous biphasic systems, and single-drop microextraction, for being the analytical microextraction techniques mostly employed with MILs. This review also introduces a classification of the MILs employed in analytical microextraction in three classes (denoted as A, B, and C) as a function of the MIL nature (metal-containing anion, metal-containing cation, and radical-containing ion), and discuss about the prospect and future trends regarding new MIL families in microextraction together with new directions expected in these procedures.

Since the development of liquid-phase microextraction (LPME), different LPME modes depending on the experimental set-up to carry out the extraction have been described. Dispersive liquid-liquid microextraction (DLLME), in which a small amount of the water-insoluble extraction solvent is dispersed in the sample, is the most successful mode in terms of number of applications reported. Advances within DLLME have been mainly shifted to the incorporation of green, smart and tunable materials as extraction solvents to improve the sustainability and efficiency of the method. In this sense, hydrophilic media represent a promising alternative since the water-miscibility of these substances increases the mass transfer of the analytes to the extraction media, leading to higher extraction efficiencies. Considering the variety of hydrophilic media that have been incorporated in LPME approaches resembling DLLME, this review aims to classify these methods in order to clarify the confusing terminology used for some of the strategies. Hydrophilic media covered in this review comprise surfactants, polar organic solvents, deep eutectic solvents, ionic liquids, water-miscible polymers, and switchable solvents. Different physicochemical mechanisms of phase separation are discussed for each LPME method, including the coacervation phenomena and other driving forces, such as pH, temperature, salting-out effect, metathesis reaction and organic solvents. LPME modes are classified (in cloud-point extraction, coacervative extraction, aqueous biphasic systems, and different DLLME modes depending on the extraction medium) according to both the nature of the water-miscible extraction phase and the driving force of the separation. In addition, the main advances and analytical applications of these methods in the last three years are described. published

A new solid-phase microextraction (SPME) fiber coating was prepared by the immobilization of the metal-organic framework (MOF) CIM-80(Al) on nitinol wires by a green in situ growth approach, using an aqueous synthetic approach, and without the need of any additional material to ensure the attachment of the MOF to the nitinol support. The coating was used for the development of headspace (HS) and direct immersion (DI) SPME methods in combination with gas chromatography and mass spectrometry (GC-MS) for the determination of polycyclic aromatic hydrocarbons (PAHs) as model compounds. Both methods were optimized and validated using the MOF-based fiber together with the commercial polydimethylsiloxane (PDMS) fiber. The MOF extraction phase exhibited superior analytical performance for most of the PAHs in HS-SPME mode (and particularly for less volatiles), while the PDMS fiber presented better results in the DI-SPME method. The analytical performance of the MOF sorbent coating in HS- and DI-SPME methods was also evaluated in urine and brewed coffee samples, without requiring any pretreatment step apart from dilution for DI-SPME experiments, thus showing suitability of the novel coatings for the analysis of complex samples. The proposed CIM-80(Al) fiber was efficient and biocompatible (for using a low cytotoxic sorbent and a biocompatible core support), and it also demonstrated stability and robustness, with inter-fiber (and inter-day) relative standard deviation values lower than 19%, and reusability for more than 80 extraction cycles using 280 °C as desorption temperature.

Ionic liquids and derivatives-mainly polymeric ionic liquids and magnetic ionic liquids-have been extensively used in microscale extraction over the past few years. Current trends in analytical sample preparation gear toward linking microextraction approaches with high-throughput sample processing to comply with green analytical chemistry requirements. A variety of high sample throughput strategies that are coupled to both ionic-liquid-based solid-phase microextraction and ionic liquid-based liquid-phase microextraction are herein reported. The review is focused on microscale extraction methods that use (i) custom-made and dedicated extraction devices, (ii) parallel extraction, (iii) magnetic-based separation, and (iv) miniaturized systems employing semi-automatic or fully automatic flow injection methods, related micro/millifluidic devices, and robotic equipment.

Metal-organic frameworks (MOFs) are attractive materials used as sorbents in analytical microextraction applications for contaminants of emerging concern (CECs) from environmental liquid matrices. The demanding specs for a sorbent in the analytical application can be comprehensively studied by considering the interactions of the target analytes with the frameworks by the use of single-crystal X-ray diffraction, computational analysis, and adsorption studies, including the kinetic ones. The current study intends a better understanding of the interactions of target CECs (particularly, propylparaben (PPB) as a model) and three Zn-based layered pillared MOFs: CIM-81 [Zn2(tz)2(bdc)] (Htz = 1,2,4-triazole and H2bdc = 1,4-benzenedicarboxylic acid) and their amino derivatives [Zn2(NH2-tz)2(bdc)] CIM-82 and [Zn2(tz)2(NH2-bdc)] CIM-83 (NH2-Htz = 3-amino-1,2,4-triazole and NH2-H2bdc = 2-amino-1,4-benzenedicarboxylic acid). The crystal structures of the two solvate compounds (dma@CIM-81 (dma = dimethylacetamide) and acetone@CIM-81) were solved by single-crystal X-ray diffraction to determine the points of interaction between the framework and the guest molecules. They also served as a starting point for the computational modeling of the PPB@CIM-81 compound, showing that up to two PPB molecules can be hosted in one of the pores, while only one can be trapped in the second pore type, leading to a maximum theoretical capacity of 291.9 mg g-1. This value is close to the value obtained by the adsorption isotherm experiment for CIM-81 (283 mg g-1). This value is, by far, higher than those previously reported for other materials for the removal of PPB from water, and also higher than the experimental values obtained for CIM-82 (54 mg g-1) and CIM-83 (153 mg g-1). The kinetics of adsorption is not very fast, with uptake of about 40% in 3 h, although a 70% release in methanol is achieved in 1 h. In addition, a further comparison of performance in analytical microextraction (requiring only 10 mg of CIM-81) was carried out together with chromatographic analysis to support all insights attained, with the method being able to monitor CECs as low as μg L-1 levels in complex environmental water samples, thus performing successfully for water monitoring even in multicomponent scenarios.

About 4 years ago, we described the pure endoscopic cervical approach to posterior mediastinum parathyroid adenomas, which we called the "prevertebral cervical approach". At that time, we had operated on three patients and did not have enough quality videos to demonstrate this approach. After broadening our experience, we present our results and show this technique through a video.From June 2015 to January 2021, information on patients undergoing the prevertebral cervical approach was obtained from a specific prospective database, including clinical presentation, biochemistry, preoperative imaging, surgical approach and patient outcomes. The step by step technique is described for both right- and left-sided adenomas, by means of a short video clip.Ten patients were operated on using this technique. Seven adenomas were right-sided and three were left-sided. The mean surgical time was 33 ± 7 min. There were neither intraoperative nor major postoperative complications. Seven patients presented with a slight subcutaneous emphysema, which did not cause complaints. All patients were discharged the day after surgery, except for one patient with a previous open neck removal of four glands due to secondary hyperparathyroidism, which required calcium replacement. Calcium and parathyroid hormone levels were normalised in the other nine patients after surgery. One patient experienced a transient recurrent laryngeal nerve injury which was spontaneously resolved within 1 month. No permanent recurrent laryngeal nerve injury was found. The postoperative cosmetic outcomes were excellent.In our experience, the pure cervical endoscopic approach has shown a high feasibility and short operation time, with excellent postoperative results regarding patient comfort, length of stay and disease cure. This approach also offers a very reasonable procedure cost, and may result in a less aggressive surgical option when compared with thoracic approaches.

Two ILs containing guanidinium cations (butylguanidinium chloride –C4Gu-Cl– and hexylguanidinium chloride –C6Gu-Cl–) were synthesized and characterized. Their cytotoxicity was also assessed, obtaining adequate CC50 values of 680 ± 99 mg·L−1 for C4Gu-Cl and 135 ± 8 mg·L−1 for C6Gu-Cl. Miniaturized aqueous biphasic systems (μ-ABSs) were developed using amounts lower than 1% (w/w) of these synthesized guanidinium-based ILs, K3PO4 as salting-out agent, and ultrapure water. The phases diagrams of both systems were determined, and the C4Gu-Cl-based μ-ABS was selected for the development of a microextraction method in combination with high performance liquid chromatography (HPLC) with fluorescence detection (FD) for the determination of five polycyclic aromatic hydrocarbons (PAHs) as model analytes. A point of the biphasic region of the C4Gu-Cl-based μ-ABS corresponding to a mixture of 0.75% (w/w) of the IL, 37.7% (w/w) of K3PO4 and 61.55% (w/w) of ultrapure water, and 30 min of equilibrium time, were selected as optimum conditions to obtain high enrichment factors and proper analytical microextraction performance. The C4Gu-Cl-based μ-ABS-HPLC-FD method exhibited low limits of detection, between 0.010 ng·L−1 and 2.0 ng·L−1, average relative recoveries of 96.7%, high enrichment factors ranging from 44.1 to 60.4, average extraction efficiencies of 61.7%, and intermediate precision relative standard deviations lower than 17% for a concentration level of 12 ng·L−1. The developed method was applied successfully in the analysis of different tap water samples.

Current trends in incorporating the principles of green chemistry in analytical methods have led to the design and usage of new solvents to replace conventional organic solvents, which characterize by their high volatility, flammability, and toxicity. Among the alternatives that have emerged, amphiphilic solvents, ionic liquids, and deep eutectic solvents are the most explored candidates in this research field. Taking advantage of the solvation properties of these new solvents, together with the synthetic versatility in the case of ionic liquids and deep eutectic solvents, a wide variety of applications of these solvents within green analytical chemistry appear in the recent literature. The aim of this article is to provide a quick summary of the state of the art on the usage of these new green solvents in analytical chemistry, particularly in liquid-phase microextraction methods (within sample preparation) and as additives or pseudostationary phases in liquid chromatography (within analytical separation methods).

Volatile methylsiloxanes (VMSs) constitute a group of compounds used in a great variety of products, particularly personal care products. Due to their massive use, they are continually discharged into wastewater treatment plants and are increasingly being detected in wastewater and in the environment at low concentrations. The aim of this work was to develop and validate a fast and reliable methodology to screen seven VMSs in water samples, by headspace solid-phase microextraction (HS-SPME) followed by gas chromatography with flame ionization detection (GC-FID). The influence of several factors affecting the extraction efficiency was investigated using a design of experiments approach. The main factors were selected (fiber type, sample volume, ionic strength, extraction and desorption time, extraction and desorption temperature) and optimized, employing a central composite design. The optimal conditions were: 65 µm PDMS/Divinylbenzene fiber, 10 mL sample, 19.5% NaCl, 39 min extraction time, 10 min desorption time, and 33 °C and 240 °C as extraction and desorption temperature, respectively. The methodology was successfully validated, showing low detection limits (up to 24 ng/L), good precision (relative standard deviations below 15%), and accuracy ranging from 62% to 104% in wastewater, tap, and river water samples.

A miniaturized extraction/preconcentration method based on an aqueous biphasic system (mu-ABS) was developed with reagents commonly used as food additives: cholinium chloride (ChCl) as main extraction phase, K2HPO4 as salting-out agent, and water as the main component (being the sample for analyses). With the aim of obtaining high enrichment factors, miniaturization, and adequate analytical performance, a point in the biphasic region with the lowest amount of ChCl was selected, corresponding to 1.55% (w/w) of ChCl, 59.5% (w/w) of K2HPO4, and 38.95% (w/w) of water. The green mu-ABS (attending to its main elements and performance mode) was used in combination with high-performance liquid chromatography with diode-array detection (HPLC-DAD) for the determination of 9 personal care products in wastewater samples. The mu-ABS-HPLC-DAD method showed high enrichment factors (up to 100), and quantitative extraction efficiencies for those compounds containing OH groups in their structure, which can undergo hydrogen bonding with ChCl. Thus, limits of quantification down to 0.8 mu g.L-1 and extraction efficiencies between 66.4 and 108% (concentration levels of 1.3 and 13 mu g.L-1) were reached for the group of parabens and the UV-filter benzophenone-3. The method is characterized by the use of non-harmful reagents and the absence of organic solvents in the entire sample preparation procedure, while being simple, low-cost, easily compatible with HPLC, and highly efficient. (C) 2021 The Author(s). Published by Elsevier B.V. Byla vyvinuta miniaturizovaná extrakční/prekoncentrační metoda založená na vodném dvoufázovém systému (mu-ABS) s činidly běžně používanými jako potravinářské přísady: chlorid cholinitý (ChCl) jako hlavní extrakční fáze, K2HPO4 jako solící činidlo a voda jako hlavní složka (vzorek pro analýzy). S cílem získat vysoké faktory obohacení, miniaturizaci a odpovídající analytický výkon byl vybrán bod v bifázické oblasti s nejnižším množstvím ChCl, což odpovídá 1,55 % (w/w) ChCl, 59,5 % (w/w) K2HPO4 a 38,95 % (w/w) vody. Zelený mu-ABS (s ohledem na jeho hlavní prvky a režim výkonu) byl použit v kombinaci s vysokoúčinnou kapalinovou chromatografií s detekcí diodovým polem (HPLC-DAD) pro stanovení 9 produktů osobní hygieny ve vzorcích odpadních vod. Metoda mu-ABS-HPLC-DAD prokázala vysoké faktory obohacení (až 100) a kvantitativní účinnost extrakce pro ty sloučeniny, které ve své struktuře obsahují OH skupiny, jež mohou podléhat vodíkové vazbě s ChCl. Pro skupinu parabenů a benzofenon-3 s UV filtrem tak bylo dosaženo mezí kvantifikace až do 0,8 mu g.l-1 a extrakčních účinností mezi 66,4 a 108 % (koncentrační hladiny 1,3 a 13 mu g.l-1). Metoda se vyznačuje použitím nezávadných činidel a absencí organických rozpouštědel v celém postupu přípravy vzorku, přičemž je jednoduchá, levná, snadno kompatibilní s HPLC a vysoce účinná.

Aqueous solutions of ionic liquids (ILs) with surface active properties were used as extraction solvents, taking advantage of their impressive solvation properties, in a green microwave-assisted solid-liquid extraction method (IL-MA-SLE) for the extraction of flavonoids from passion fruit and mango leaves. The extraction method was combined with high-performance liquid chromatography and photodiode-array detection (HPLC-PDA) and optimized by response surface methodology using the Box-Behnken experimental design. Under optimum conditions, the extraction efficiency of six structurally different IL-based surfactants was evaluated. Thus, imidazolium-, guanidinium- and pyridinium-type ILs with different tailorable characteristics, such as side chain length and multicationic core, were assessed. The decylguanidinium chloride ([C10Gu+][Cl&ndash, ]) IL-based surfactant was selected as key material given its superior performance and its low cytotoxicity, for the determination of flavonoids of several samples of Passiflora sp. and Mangifera sp. leaves from the Canary Islands, and using as target analytes: rutin, quercetin and apigenin. The analysis of 50 mg of plant material only required 525 &micro, L of the low cytotoxic IL-based surfactant solution at 930 mM, 10.5 min of microwave irradiation at 30 &deg, C and 50 W, which involves a simpler, faster, more efficient and greener method in comparison with other strategies reported in the literature for obtaining bioactive compounds profiles from plants.

This review overviews the main developments achieved in analytical sample preparation regarding the use of solid sorbents as extractants in different sorbent-based miniaturized, micro-scale and microextraction methods. Two main groups are proposed for the classification of the current approaches, based on their operational mode: micro-solid-phase extraction (µ-SPE) and solid-phase microextraction (SPME), while describing their respective main sub-modes: static- and dispersive-µ-SPE, and SPME with fibers and in tube SPME. Furthermore, other important sorbent-based microscale approaches (e.g., stir bar sorptive extraction, stir cake sorptive extraction, stir bar sorptive-dispersive microextraction, and thin film microextraction, among others) are also considered., MJT-R thanks Spanish Ministry of Science and Innovation, for her Juan de la Cierva – formación contract and Aragon Regional Government and the European Social Fund (E07_20R). IP-F thanks the Canary Agency of Research and Innovation (ACIISI), co-funded by the European Social Fund, for her FPI PhD fellowship. VP thanks the Spanish Ministry of Economy and Competitiveness (MINECO) for the project MAT2017-89207-R.

This paper proposes a new sustainable and simple strategy for the micro-scale extraction of phenolic compounds from grapevine leaves with analytical purpose. The method is based on a microwave-assisted solid-liquid extraction approach (MA-SLE), using an aqueous solution of an ionic liquid (IL)-based surfactant as extraction phase. The method does not require organic solvents, nor any clean-up step, apart from filtration prior to the injection in the analytical system. Two IL-based surfactants were evaluated, and the method was optimized by using experimental designs, resulting in the use of small amounts of sample (100 mg) and extraction phase (2.25 mL), low concentrations of the selected 1-hexadecyl-3-butyl imidazolium bromide IL (0.1 mM), and 30 min of extraction time. The proposed methodology was applied for the determination of the polyphenolic pattern of six different varieties of Vitis vinifera leaves from the Canary Islands, using high-performance liquid chromatography and photodiode array detection for the quantification of the compounds. The proposed MA-SLE approach was greener, simpler, and more effective than other methods, while the results from the analysis of the leaves samples demonstrate that these by-products can be exploited as a source of natural compounds for many applications.

Ionic liquids (ILs) are a group of salts composed of bulky organic cations and organic or inorganic anions, with melting points below 100°C. They present a unique set of properties, such as low vapor pressure at room temperature, high thermal stability, and synthetic tunability. Due to the possibility of tailoring these solvents by the appropriate selection of cations and anions together with their low toxicity, ILs stand as the most promising alternative to conventional halogenated organic solvents in liquid-phase extraction methods. Thus different methods for the extraction of organic compounds from environmental, food, and biological samples include ILs and their derivatives as extraction solvents in the strategies. Methods such as microwave- and ultrasound-assisted extraction; aqueous biphasic systems; and mainly liquid-phase microextraction methods, including dispersive liquid-liquid microextraction, single-drop microextraction, and hollow-fiber liquid-phase microextraction, have been developed taking advantage of the singular properties of ILs for the analytic determination of organic compounds.

Ionic liquids (ILs) are a group of non-conventional salts with melting points below 100 degrees C. Apart from their negligible vapor pressure at room temperature, high thermal stability, and impressive solvation properties, ILs are characterized by their tunability. Given such nearly infinite combinations of cations and anions, and the easy modification of their structures, ILs with specific properties can be synthesized. These characteristics have attracted attention regarding their use as extraction phases in analytical sample preparation methods, particularly in liquid-phase extraction methods. Given the liquid nature of most common ILs, their incorporation in analytical sample preparation methods using solid sorbents requires the preparation of solid derivatives, such as polymeric ILs, or the combination of ILs with other materials to prepare solid IL-based composites. In this sense, many solid composites based on ILs have been prepared with improved features, including magnetic particles, carbonaceous materials, polymers, silica materials, and metal-organic frameworks, as additional materials forming the composites. This review aims to give an overview on the preparation and applications of IL-based composites in analytical sample preparation in the period 2017-2020, paying attention to the role of the IL material in those composites to understand the effect of the individual components in the sorbent. Iontové kapaliny (IL) jsou skupina nekonvenčních solí s teplotou tání pod 100 °C. Kromě jejich zanedbatelné tenze par při pokojové teplotě, vysoké tepelné stability a příznivých solvatačních vlastností se IL vyznačují svou laditelností. Vzhledem k téměř nekonečné kombinaci kationtů a aniontů a snadné modifikaci jejich struktur lze syntetizovat IL se specifickými vlastnostmi. Tyto vlastnosti přitahovaly pozornost, pokud jde o jejich použití jako extrakčních fází v metodách přípravy analytických vzorků, zejména v metodách extrakce v kapalné fázi. Vzhledem k tekuté povaze nejběžnějších IL jejich začlenění do metod analytického zpracování vzorků s použitím tuhých sorbentů vyžaduje přípravu derivátů, jako jsou polymerní IL, nebo kombinace IL s jinými materiály pro přípravu tuhých kompozitů na bázi IL. V tomto smyslu bylo připraveno mnoho tuhých kompozitů na bázi IL s vylepšenými vlastnostmi, včetně magnetických částic, uhlíkatých materiálů, polymerů, materiálů z oxidu křemičitého a metalo-organických struktur, jako dalších materiálů tvořících kompozity. Cílem této studie je poskytnout přehled o přípravě a aplikacích kompozitů na bázi IL při analytickém zpracování vzorků v období 2017–2020, přičemž je třeba věnovat pozornost úloze materiálu IL v těchto kompozitech, aby bylo možné pochopit účinek jednotlivých složek sorbentu.

Since the introduction of the Green Analytical Chemistry guidelines, there has been an increasing concern on the sustainability of sample preparation approaches, particularly if considering they constitute the most time-consuming step of the analytical method and the main source of laboratory wastes. Among the alternatives explored, it is important to highlight the miniaturization of the extraction methods, which has been accompanied by the seek of greener solvents and sorbents. Biopolymers emerge as potential candidates to be used as sorbents in microextraction schemes given their biodegradability, versatility, and easily functionalization. This review offers an overview on biopolymers (chitosan, cellulose, alginate, and agarose) in sorbent-based microextraction approaches, paying attention to the preparation of the sorbent and the format in which biopolymers are incorporated into the sorbent/device, thus implying a specific microextraction approach, their role in the resulting sorbent material, and the reported analytical applications, covering environmental, food, and bioclinical analysis. Agencia Canaria de Investigación, Innovación y Sociedad de la Información University of Turin Ministerio de Ciencia, Innovación y Universidades Ministerio de Economía, Industria y Competitividad