Determination of non-steroidal anti-inflammatory drugs in water samples by solid-phase microextraction based sol–gel technique using poly(ethylene glycol) grafted multi-walled carbon nanotubes coated fiber

Green and efficient magnetic micro-solid phase extraction utilizing tea waste impregnated with magnetic nanoparticles for the analysis of ibuprofen in water samples by using UV-vis spectrophotometry

A green method based on magnetic micro-solid phase extraction (MNP-TW-μ-SPE) of tea waste impregnated with magnetic nanoparticles (MNP-TW) was developed for the extraction of ibuprofen (IBP) in water samples prior to UV-Vis spectrophotometric analysis. Experimenting parameters that affect the extraction efficiency of IBP, such as pH of the sample solution, sorbent dosage, extraction time, ionic strength, volume of the sample, type of desorption solvent, desorption time, and desorption volume, were studied and optimized in detail. The characterization studies for the MNP-TW were carried out by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectrometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, a vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Under the optimum conditions, the linearity ranges from 30 to 700 μg L-1 for IBP, with determination coefficients (R2) of 0.9983. The limit of detection (LOD) and limit of quantification (LOQ) were 9.40 μg L-1 and 28.50 μg L-1, respectively. The method also demonstrated good precision in reproducibility (RSD ≤ 1.53%), repeatability (RSD ≤ 1.48%), and recovery (86-115%). This method represents the advantages of low solvent consumption, flexibility, and better sensitivity compared to other studies employing spectrophotometric analysis. The usage of tea waste in the extraction process presents many advantages, as it is biodegradable, versatile, and contributes to an intelligent and sustainable economic strategy projected toward a circular economy approach.

Polymeric ionic liquid sorbent coatings in thin film microextraction: Insight into sorbent selectivity for pesticides and cannabinoids

Polymeric ionic liquid (PIL) sorbent coatings consisting of polymerizable cations and anions were employed as sorbent coatings in thin film microextraction (TFME) for the extraction of pesticides and cannabinoids. The blades consisted of a thin film of PIL sorbents chemically bonded to vinyltrimethoxysilane-functionalized nitinol sheets. The imidazolium- or ammonium-based PIL sorbents contained aromatic benzyl moieties as well as polar hydroxyl groups or aliphatic functional groups within the chemical structure of the IL monomer. The chemical structure of the IL crosslinkers of the PILs were kept constant across each sorbent, except for the anion, which consisted of either bis[(trifluoromethyl)sulfonyl]imide ([NTf2-]), p-styrenesulfonate ([SS-]), or 3-sulfopropyl acrylate ([SPA-]). Temperature, salt content, and methanol content were optimized as extraction conditions to maximize pesticide-cannabinoid selectivity using Doehlert design of experiments (DOE). Effects of these three factors on selectivity and extraction efficiency are discussed. The optimal extraction conditions consisting of sample temperature (31°C), sodium chloride (30% w/v), and methanol content (0.25% v/v) are compared to initial sorbent screening conditions at a sample temperature of 40°C, 15% (w/v) sodium chloride, and 2.5% (v/v) methanol content. PIL sorbent swelling behavior at different salt and methanol content conditions and its effect on extraction efficiency are hypothesized. Selectivity factors for the sorbents indicated that aromatic moieties within the IL monomer may enhance pesticide-cannabinoid selectivity under optimized conditions, but the extraction efficiency of pesticides that are known to coelute with cannabinoids in the chromatographic separation may be enhanced by employing sorbent coatings with [SPA-] anions.

Photocatalysis-PMS oxidation system based on CQDs-doped carbon nitride nanosheets for degradation of residual drugs in water

Graphite-like carbon nitride (g-C3N4) is favored for its excellent physicochemical properties. However, the high complexation rate of photogenerated carriers greatly limits its practical applications. Based on this, a novel CQDs-doped carbon nitride nanosheets composite (CNS/CQDs) was prepared and applied to the visible light-induced activation of peroxymonosulfate (PMS) for meloxicam (Mel) and tetracycline (TC) degradation. The photocatalytic degradation of Mel and TC were remarkably promoted in the CNS/CQDs+PMS+vis system. Mel photodegradation of 99.90% was achieved over 30 min with 20 mg CNS/CQDs and 20 mg PMS at pH11. And TC photodegradation of 95.97% was achieved over 45 min with 20 mg CNS/CQDs and 20 mg PMS at nature pH6.5. The TOC mineralization rates of Mel and TC were 75.49% and 52.00%, respectively. The transient photocurrent response and electrochemical impedance measurements (EIS) results indicated that the doping of CQDs could improve the charge transfer efficiency of pure g-C3N4, and CNS/CQDs had a low charge transfer resistance. Capture experiments and EPR tests explored the effective actives in the CNS/CQDs+PMS+vis system. Possible degradation pathways of Mel were also analyzed. This study provides valid residual drugs degradation under the dual conditions of visible light catalytic oxidation and persulfate oxidation, which will be a novel perspective for advanced oxidation technology to effectively remove organic pollutants from water.

Keggin type phosphotungstic acid intercalated copper-chromium-layered double hydroxide reinforced porous hollow fiber as a sorbent for hollow fiber solid phase microextraction of selected chlorophenols besides their quantification via high performance liquid chromatography

Herein, a copper-chromium-layered double hydroxide (Cu/Cr-LDH) was synthesized by the co-precipitation method. The Cu/Cr-LDH was intercalated to the Keggin-type polyoxometalate (H₃PW₁₂O₄₀). The modified LDH accommodated in the pores of hollow fiber (HF), to prepare the extracting device for the HF-solid phase microextraction method (HF-SPME). The method was used for the extraction of 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6- trichlorophenol from tap water, river water, and tea sample. The extracted target analytes were quantified via high-performance liquid chromatography-UV detection. The figures of merit of the method such as, linear dynamic ranges (LDRs), limit of detections (LODs) and, limit of quantifications (LOQs), were determined based on the obtained optimum condition. Based on the results, the LDR was between 1 and 500 μg L ^- 1 and r² higher than 0.9960. The LODs and LOQs were obtained in the ranges of 0.28-0.36 µg L ^- 1 and 0.92-1.1 µg L ^- 1, respectively. The relative standard deviations ((RSDs% for inter-and intra-day) of the method for the extraction of target analytes were calculated in two different concentrations of (2 and 10 μg L ^- 1) and (5 and 10 μg L ^- 1) between 3.70% - 5.30% and 3.50% - 5.70%-respectively. The enrichment factors were obtained between 57 and 61. In order to investigate the accuracy of the method, also the relative recovery was obtained, between 93 and 105%. Finally, the proposed method was used for the extraction of the selected analytes in different water and tea samples.

Magnetic Solid-Phase Extraction Based on Magnetite-Multiwalled Carbon Nanotubes of Non-Steroidal Anti-Inflammatories from Water Followed by LC-ESI-MS/MS

An analytical method based on liquid chromatography-electrospray ionization-tandem mass spectrometry detection (LC-ESI-MS/MS) has been developed for the determination of pharmaceutical compounds in water samples. Five non-steroidal anti-inflammatory drugs (NSAIDs) namely Naproxen, Ketoprofen, Piroxicam, Diflunisal and Celecoxib were investigated. Magnetic solid phase extraction (MSPE) was used for sample pre concentration of water samples and magnetic carbon nanotubes (Fe3O4-MWCNTs) were considered as solid phase extraction sorbent. Important parameters influencing the extraction efficiency such as nature and volume of eluent, sample pH and adsorbent mass were optimized. The developed MSPE method involved 75 mg of Fe3O4-MWCNTs sorbent, 5 mL of water sample at pH = 4 and 5 mL of 10% ammonia in methanol in the elution step. Under the optimized extraction conditions, linearity, detection and quantification limits and reproducibility were evaluated. The proposed method was successfully applied to the analysis of NSAIDs in surface waters, and mean recoveries of all the NSAIDs were above 90% with relative standard deviations < 17%. The detection and quantification limits were comprised between 0.05-3.6 ng.mL-1 and 0.2-11.9 ng.mL-1, respectively.

Solventless Microextration Techniques for Pharmaceutical Analysis: The Greener Solution

Extensive efforts have been made in the last decades to simplify the holistic sample preparation process. The idea of maximizing the extraction efficiency along with the reduction of extraction time, minimization/elimination of hazardous solvents, and miniaturization of the extraction device, eliminating sample pre- and posttreatment steps and reducing the sample volume requirement is always the goal for an analyst as it ensures the method’s congruency with the green analytical chemistry (GAC) principles and steps toward sustainability. In this context, the microextraction techniques such as solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), microextraction by packed sorbent (MEPS), fabric phase sorptive extraction (FPSE), in-tube extraction dynamic headspace (ITEX-DHS), and PAL SPME Arrow are being very active areas of research. To help transition into wider applications, the new solventless microextraction techniques have to be commercialized, automated, and validated, and their operating principles to be anchored to theory. In this work, the benefits and drawbacks of the advanced microextraction techniques will be discussed and compared, together with their applicability to the analysis of pharmaceuticals in different matrices.

Solid-phase extraction of non-steroidal anti-inflammatory drugs in human plasma and water samples using sol-gel-based metal-organic framework coating

In this research, the Cu-based metal-organic framework (MOF-199) was fabricated and coated on the stainless steel mesh as substrates through sol-gel procedure. Then the coated substrates were placed in a small column known as solid-phase extraction cartridge. The SPE based coated stainless steel mesh coupled with high-performance liquid chromatography-UV detector (HPLC-UV) was used for the fast extraction, and quantification of non-steroidal anti-inflammatory drugs (NSAIDs) from human plasma and water samples. To find optimum extraction conditions, the impacts of effective parameters on analytical performance like sample pH, sample volume, type, and volume of desorption solvent were optimized. At the optimized conditions, calibration graphs of analytes were linear in the concentration range of 0.03-300 ng mL^-1 for water samples, and 0.1-200 ng mL^-1 for plasma samples. The correlation coefficients were in the range of 0.9938 to 0.9989. Also, the limits of detection (LODs) were from 0.01 to 0.02 ng mL^-1 for water samples and 0.03 to 0.1 ng mL^-1 for plasma samples. The cartridge repeatability was studied at different values, and the relative standard deviations (RSDs%) were achieved between 3.5 and 5.1%. Consequently, this procedure was successfully used in the extraction and detection of NSAIDs in real water and plasma samples with relative recoveries ranged from 93.6 to 99.6%.

Microstructured optical fibers sensor modified by deep eutectic solvent: Liquid-phase microextraction and detection in one analytical device

A sensitive optical sensor based on hollow core microstructure optical fibers modified with deep eutectic solvent was produced for the first time. An easy procedure for the modification of hollow-core microstructure optical fibers with deep eutectic solvent was developed. Deep eutectic solvents based on natural monoterpenoids and fatty acids were investigated for glass surface modification. The sensor was used for the determination of non-steroidal anti-inflammatory drugs (mefenamic acid, diclofenac, flurbiprofen and ketoprofen) in human urine samples. The mechanism of the sensor response was investigated and discussed. Liquid-phase microextraction of non-steroidal anti-inflammatory drugs was implemented in deep eutectic solvent phase supported in the inner surface of hollow-core microstructure optical fibers followed by transmission spectra measurement in one analytical device. The preconcentration step performed directly in the analytical device allowed to obtain high sensitivity and selectivity. The limits of detection calculated from the calibration plots based on 3σ were 3 μg L^-1 for all target analytes.

Overview of Sample Preparation and Chromatographic Methods to Analysis Pharmaceutical Active Compounds in Waters Matrices

In the environment, pharmaceutical residues are a field of particular interest due to the adverse effects to either human health or aquatic and soil environment. Because of the diversity of these compounds, at least 3000 substances were identified and categorized into 49 different therapeutic classes, and several actions are urgently required at multiple steps, the main ones: (i) occurrence studies of pharmaceutical active compounds (PhACs) in the water cycle; (ii) the analysis of the potential impact of their introduction into the aquatic environment; (iii) the removal/degradation of the pharmaceutical compounds; and, (iv) the development of more sensible and selective analytical methods to their monitorization. This review aims to present the current state-of-the-art sample preparation methods and chromatographic analysis applied to the study of PhACs in water matrices by pinpointing their advantages and drawbacks. Because it is almost impossible to be comprehensive in all PhACs, instruments, extraction techniques, and applications, this overview focuses on works that were published in the last ten years, mainly those applicable to water matrices.

Molecularly imprinted polymer-based electrochemical sensors for environmental analysis

The ever-increasing presence of contaminants in environmental waters is an alarming issue, not only because of their harmful effects in the environment but also because of their risk to human health. Pharmaceuticals and pesticides, among other compounds of daily use, such as personal care products or plasticisers, are being released into water bodies. This release mainly occurs through wastewater since the treatments applied in many wastewater treatment plants are not able to completely remove these substances. Therefore, the analysis of these contaminants is essential but this is difficult due to the great variety of contaminating substances. Facing this analytical challenge, electrochemical sensing based on molecularly imprinted polymers (MIPs) has become an interesting field for environmental monitoring. Benefiting from their superior chemical and physical stability, low-cost production, high selectivity and rapid response, MIPs combined with miniaturized electrochemical transducers offer the possibility to detect target analytes in-situ. In most reports, the construction of these sensors include nanomaterials to improve their analytical characteristics, especially their sensitivity. Moreover, these sensors have been successfully applied in real water samples without the need of laborious pre-treatment steps. This review provides a general overview of electrochemical MIP-based sensors that have been reported for the detection of pharmaceuticals, pesticides, heavy metals and other contaminants in water samples in the past decade. Special attention is given to the construction of the sensors, including different functional monomers, sensing platforms and materials employed to achieve the best sensitivity. Additionally, several parameters, such as the limit of detection, the linear concentration range and the type of water samples that were analysed are compiled.

Magnetic Solid-Phase Extraction Based on Poly 4-Vinyl Pyridine for HPLC-FLD Analysis of Naproxen in Urine Samples

A magnetic solid phase extraction technique followed by liquid chromatography with a fluorescence detector for naproxen analysis in human urine samples was developed. The method includes the extraction of naproxen with a magnetic solid synthetized with magnetite and poly 4-vinylpriridine, followed by the magnetic separation of the solid phase and desorption of the analyte with methanol. Under optimal conditions, the linear range of the calibration curve was 0.05–0.60 μg L⁻¹, with a limit of detection of 0.02 μg L⁻¹. In all cases values of repeatability were lower than 5.0% with recoveries of 99.4 ± 1.3%. Precision and accuracy values are adequate for naproxen (Npx) analysis in urine samples.

Applications of Graphene and Its Derivatives in Chemical Analysis

In this review, the applications of graphene and its derivatives in the chemical analysis have been described. The properties of graphene materials which are essential for their use in chemical and biochemical analysis are characterized. The materials are used in sensors and biosensors, in electrochemistry, in chromatography and in the sample preparation techniques. Chemical and electrochemical sensors containing graphene materials are useful devices for detecting some chemical and biochemical compounds. Chromatographic columns for HPLC with graphene containing stationary phases may be used for separation of polar and nonpolar components of some specific mixtures. Graphene materials could be successfully employed during sample preparation for analysis with SPE, magnetic SPE, and SPME techniques. HighlightsThe review of the applications of graphene (G) and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), in chemical and biochemical analysis is proposed.The electron donor-acceptor and proton donor-acceptor interactions for the graphene based materials - analytes systems and their impact on the analysis results are discussed, particularly:    i) in electrochemistry,ii) in chromatography,iii) in modern sample preparation techniquesiv) in sensors of different types.The essence of the thermal stability and the nomenclature of the graphene based materials in their different applications in chemical systems of different classes was discussed (and suggested).The benefits of using SPME fibers with immobilized graphene materials have been presented in detail.

Magnetic polyethyleneimine functionalized reduced graphene oxide as a novel magnetic sorbent for the separation of polar non-steroidal anti-inflammatory drugs in waters

A novel magnetic polyethyleneimine modified reduced graphene oxide (Fe₃O₄@PEI-RGO) had been prepared and then was successfully employed to extract three polar non-steroidal anti-inflammatory drugs (NSAIDs) in different water matrices for the first time coupled with high performance liquid chromatography-diode array detector (HPLC-DAD). The magnetic polyethyleneimine (Fe₃O₄@PEI) composite was first synthesized via one-pot hydrothermal approach and then the Fe₃O₄@PEI-RGO composite was fabricated on the basis of a simple self-assemble approach between positive charged Fe₃O₄@PEI and negative charged GO sheets via electrostatic interaction followed by chemical reduction of GO to RGO. The as-prepared Fe₃O₄@PEI-RGO composite was carefully characterized by transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), thermal gravimetric analyzer (TGA), vibrating sample magnetometer (VSM) and zeta potential analysis. As a surface modifier of RGO, PEI not just changed the polarity of RGO to some extent but also offered more adsorption sites to polar NSAIDs. Compared with Fe₃O₄@PEI, Fe₃O₄-RGO and Fe₃O₄@PEI-GO, the as-prepared Fe₃O₄@PEI-RGO composite, which combined the advantage of PEI and RGO, showed higher extraction efficiency for polar NSAIDs. In addition, the adsorption mechanism was also studied. The analytical parameters influencing the extraction efficiency were optimized in detail. A satisfactory performance was obtained under the optimal conditions. The calibration lines were linear over the concentration in the range of 1-800 μg L^-1 for all the analytes with determination coefficients (r²) varying from 0.9972 to 0.9986. The limits of detection (LODs) were 0.2 μg L^-1. The recoveries were between 91.20% and 101.13% with relative standard deviations (RSDs) in the range of 1.09-7.34%. Overall, a fast, convenient, sensitive and eco-friendly method was successfully proposed and became a promising approach for the determination of trace polar NSAIDs in complex matrices.

Solid-phase microextraction based on an agarose-chitosan-multiwalled carbon nanotube composite film combined with HPLC-UV for the determination of nonsteroidal anti-inflammatory drugs in aqueous samples

We describe the preparation, characterization, and application of a composite film adsorbent based on blended agarose-chitosan-multiwalled carbon nanotubes for the preconcentration of selected nonsteroidal anti-inflammatory drugs in aqueous samples before determination by high performance liquid chromatography with ultraviolet detection. The composite film showed a high surface area (4.0258 m² /g) and strong hydrogen bonding between the multiwalled carbon nanotubes and agarose/chitosan matrix, which prevent adsorbent deactivation and ensure long-term stability. Several parameters, such as sample pH, addition of salt, extraction time, desorption solvent, and concentration of multiwalled carbon nanotubes in the composite film were optimized using a one-factor-at-time approach. The optimum extraction conditions obtained were as follows: isopropanol as conditioning solvent, 10 mL of sample solution at pH 2, extraction time of 30 min, stirring speed of 600 rpm, 100 μL of isopropanol as desorption solvent, desorption time of 5 min under ultrasonication, and 0.4% w/v of composite film. Under the optimized conditions, the calibration curve showed good linearity in the range of 1-500 ng/mL (r²  = 0.997-0.999), and good limits of detection (0.89-8.05 ng/mL) were obtained with good relative standard deviations of < 4.59% (n = 3) for the determination of naproxen, diclofenac sodium salt, and mefenamic acid drugs.

Determination of acidic non-steroidal anti-inflammatory drugs in aquatic samples by liquid chromatography-triple quadrupole mass spectrometry combined with carbon nanotubes-based solid-phase extraction

A solid-phase extraction (SPE) method based on multi-walled carbon nanotubes (CNT) was developed for the determination of 12 acidic non-steroidal anti-inflammatory drugs (NSAIDs) in surface waters and tap water. Pristine and functionalised CNTs were evaluated as sorbent materials. Batch experiments were used to optimise sorption and desorption conditions (sorbent type and amount, adsorption time, pH). The adsorption equilibrium was reached after 8 to 48 h duration, which increased with the pH of solution. Non-agglomerated pristine CNTs (20 mg) showed the most optimal adsorption (94 to 100%) for all of the analytes after a 30-min contact period in acidified water solutions (100 mL). The compounds retained at those conditions were recovered by 40 to 95% by using 5% ammonium hydroxide in methanol as the desorbing solution at ambient conditions. A comprehensive liquid chromatography coupled to triple quadrupole mass spectrometry (LC-QqQ-MS/MS) was used for the analysis of real water samples. The method showed sufficient recovery (65-125%) and good precision (2-14% relative standard deviation (RSD)). The limits of detection and quantification ranged between 0.01 and 1.3 ng L^-1 and 0.04 and 3.9 ng L^-1. Only diclofenac and ibuprofen were found in the analysed surface water samples from Latvia (n = 10) and Norway (n = 14). Diclofenac was found at 1.7-8.4 ng L^-1 concentration in two samples of surface waters, whereas the concentrations of ibuprofen ranged between 1.0 and 9.2 ng L^-1 in seven samples collected in Norway and 3.9-17 ng L^-1 in three samples from Latvia.

A Poly(ethylenglycol) Functionalized ZIF-8 Membrane Prepared by Coordination-Based Post-Synthetic Strategy for the Enhanced Adsorption of Phenolic Endocrine Disruptors from Water

Metal–organic framework (MOF) membranes have received increasing attention as adsorbents, yet single phase MOF membranes have certain limitations, which frustrate their capacity performance. In this work a MOF composite membrane was successfully prepared by a facile and green strategy through reasonable design. At first, a defect-free ZIF-8 membrane was fabricated on an ionic liquid modified pencil bar by a solvothermal method. Then, a novel poly(ethylenglycol) functionalized ZIF-8 composite membrane (ZIF-8/PEG-NH₂) was prepared through a flexible coordination-based post-synthetic modification strategy. We found that reaction time and temperature were two crucial factors for successfully fabricating well-defined ZIF-8/PEG-NH₂ membrane. Besides, the adsorption of phenolic endocrine disruptors (e.g., 4-nonylphenol) on original ZIF-8 membrane and ZIF-8/PEG-NH₂ membrane was investigated, and the good adsorption selectivity of ZIF-8/PEG-NH₂ membrane towards 4-nonylphenol was demonstrated, with high adsorption capacity and fast adsorption dynamics. Excitingly, such ZIF-8/PEG-NH₂ membrane was successfully employed for the selective detection of 4-nonylphenol from environmental water samples, demonstrating its great application potential in environmental monitoring.

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE “acetonitrile stacking” preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L⁻¹ and 2.91 and 3.86 µg∙L⁻¹, respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers.

Applications of molecularly imprinted polymers for solid-phase extraction of non-steroidal anti-inflammatory drugs and analgesics from environmental waters and biological samples

The occurrence of pharmaceuticals used as non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics in the aquatic environment is a threat to humans and aquatic species at large. The primary route of these pharmaceuticals to aquatic environment is through human waste such as urine and faeces. The application of molecularly imprinted polymers (MIPs) in the solid-phase extraction (SPE) of such pollutants from environmental and biological samples is important for the pre-concentration of compounds and selectivity of the analytical methods. To date, there are still limited commercial suppliers of MIPs. However, it is easy to synthesize such polymers via non-covalent imprinting approach using easily available and affordable reagents. Therefore, the applications of MIPs in the SPE of NSAIDs and analgesics from environmental and biological samples are reviewed. This is very important because despite the fact that review articles on applications of MIPs for organic compounds have been reported, very little has focussed on NSAIDs and analgesics which are the major studied pharmaceuticals in the environment and biological samples. The review also brings out important aspects of common reagents used including the template molecules during MIP synthesis. Application and future trends are also discussed. Gaps such as little use of environmental friendly reagents such as ionic liquids have been identified. Also, the lack of MIP applications to some compounds such as fenoprofen has been observed which is likely to be developed in the near future.

Development of molecularly imprinted polymers (MIPs) as a solid phase extraction (SPE) sorbent for the determination of ibuprofen in water

Ibuprofen-templated molecularly imprinted polymers (MIPs) demonstrated high selectivity to ibuprofen in the presence of closely related compounds, naproxen and ketoprofen.

Application of nanocomposite-based sorbents in microextraction techniques: a review

This review provides a general overview of the recent trends for the preparation of nanocomposites and their applications in microextraction techniques.

A Simple Approach to Enhance the Water Stability of a Metal-Organic Framework

A facile method to improve the feasibility of water-unstable metal-organic frameworks in an aqueous environment has been developed that involves imbedding in a polymer monolith. The effect of compartment type during polymerization plays a significant role in maintaining the crystalline structure and thermal stability of the MOFs, which was confirmed by powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA), respectively. The MOF-polymer composite prepared in a narrow compartment (column, ID 0.8 mm) has better thermal and chemical stability than that prepared in a broad compartment (vial, ID 7 mm). The developed MOF-polymer composite was applied as an adsorbent in solid-phase microextraction of nine non-steroidal anti-inflammatory drugs (NSAIDs) and could be used for extraction more than 30 times, demonstrating that the proposed approach has potential for industrial applications.

Determination of Aromatic Amines Using Solid-Phase Microextraction Based on an Ionic Liquid-Mediated Sol-Gel Technique

A headspace solid-phase microextraction (HS-SPME) method was developed for isolation of monocyclic aromatic amines from water samples followed by gas chromatography-flame ionization detector (GC-FID). In this work, the effect of the presence of ionic liquid (namely, 1-hexyl-3-methyl-imidazolium hexafluorophosphate [C6MIM][PF6]) was investigated in the sol-gel coating solutions on the morphology and extraction behavior of the resulting hybrid organic-inorganic sol-gel sorbents utilized in SPME. Hydroxy-terminated poly(dimethylsiloxane) (PDMS) was used as the sol-gel active organic component for sol-gel hybrid coatings. Two different coated fibers that were prepared are PDMS and PDMS-IL ([C6MIM][PF6]) fibers. Under the optimal conditions, the method detection limits (S/N = 3) with PDMS-IL were in the range of 0.001-0.1 ng/mL and the limits of quantification (S/N = 10) between 0.005 and 0.5 ng/mL. The relative standard deviations for one fiber (n = 5) were obtained from 3.1 up to 8.5% and between fibers or batch to batch (n = 3) in the range of 5.3-10.1%. The developed method was successfully applied to real water and juice fruits samples while the relative recovery percentages obtained for the spiked water samples at 0.1 ng/mL were from 83.3 to 95.0%.