Solid-phase extraction combined with a spectrophotometric method for determination of Bisphenol-A in water samples using magnetic molecularly imprinted polymer

A novel magnetite C18/paracetamol/alginate adsorbent bead for simultaneous extraction of synthetic antioxidants and bisphenol A in water samples

A novel magnetic composite bead was synthesized using carbon 18, paracetamol and alginate (mC18/Pa/Alg). The bead was applied to simultaneously adsorb butylated hydroxytoluene, butylated hydroxyanisole, and bisphenol A from water samples by magnetic solid-phase extraction (MSPE). The adsorbed analytes were determined by gas chromatography-flame ionization detection. The morphology and composition of the bead were examined by field emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction analysis, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface analysis. The best condition of MSPE included an adsorbent bead made with 0.8% sodium alginate, a 0.3 g adsorbent dose, a sample solution pH of 7, and a desorption time of 20 min in methanol. The proposed method exhibited linearity at concentrations between 0.015 and 1.00 μg mL-1 of analytes. Limits of detection ranged from 6.86 to 9.66 ng mL-1. Recoveries from 80.3 to 100.1% were achieved with interday and intraday precisions (RSDs) of 0.4-4.3%.

Innovative approaches to suppress non-specific adsorption in molecularly imprinted polymers for sensing applications

Molecularly imprinted polymers (MIPs) are synthetic antibodies developed to bind selectively with specific molecules. They function through a particular recognition process involving their cavities and functional groups. Nevertheless, functional groups located outside these cavities are the main cause of non-specific molecule binding, thus reducing the effectiveness of MIPs in sensing applications. This work focused on enhancing the selectivity and performance of MIPs through electrostatic modification with surfactants. The study investigates the use of two surfactants, namely sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB), to eliminate non-specific adsorption in MIPs. The binding isotherms of the target molecule sulfamethoxazole (SMX) on MIPs and non-imprinted polymers (NIPs) were analyzed, showing higher adsorption capacity of MIPs due to the specific cavities. The modification with SDS or CTAB effectively eliminated non-specific adsorption in MIPs. The kinetic adsorption behavior further demonstrated the efficacy of MIP+--SDS/CTAB in the selective adsorption of SMX. Calibration curves showcase the methodology's analytical capabilities, achieving low limit of detection for SMX 6 ng mL-1 using MIP +-SDS. The stability study confirmed that the developed MIP +/--SDS/CTAB remains stable even at high temperatures, demonstrating its suitability for on-site applications. The methodology was successfully applied to detect SMX in milk and water samples, achieving promising recoveries. Overall, the electrostatic modification of MIPs with surfactants emerges as a valuable strategy for enhancing selectivity and performance in target molecule recognition and detection.

A new copper nanocluster surface molecular imprinted polymethacrylic acid probe for ultratrace trichlorophenol based on in situ-generated nanogold SPR effects

A new coinage metal nanocluster surface molecularly imprinted polymethacrylic acid nanoprobe (NC@MIP) for the selective determination of 2,4,6-trichlorophenol (TCP) was prepared via microwave synthesis using 2,4,6-trichlorophenol as a template molecule, copper nanoclusters (CuNC) as a nanosubstrate, and methacrylic acid as a polymer monomer. It was found that the copper nanocluster MIP (CuNC@MIP) shows the strongest catalytic performance for the reduction of HAuCl4 by hydrazine hydrate for the on-site generation of gold nanoparticles (AuNPs) with the surface plasmon resonance (SPR) effects of resonance surface-enhanced Raman scattering (SERS) and resonance Rayleigh scattering (RRS) as well as absorption (Abs). When TCP was added, the CuNC@MIP nanoprobe and TCP-formed CuNC@MIP-TCP nanoenzyme with stronger catalytic activity generated more AuNPs, and the trimodal analytical signal was enhanced linearly. Therefore, a new SERS/RRS/Abs trimodal sensing platform for TCP was constructed, which was simple, rapid, sensitive, and selective. For each mode, the linear ranges were 0.0075-0.075, 0.010-0.10, and 0.010-0.10 nmol L-1, and the detection limits were 0.0010, 0.021, and 0.043 nmol L-1, respectively. The relative deviation of TCP in different water quality was 0.47%-2.5% and the recovery rate was 94.6%-108.6%.

Molecularly imprinted photopolymers combined with smartphone-based optical sensing for selective detection of bisphenol A in foods

Bisphenol A (BPA), known for its endocrine-disrupting properties and potential to leach into food products, has led to significant food safety concerns. Therefore, the development of sensitive and selective BPA rapid detection methods is crucial. In this study, molecularly imprinted solid-phase extraction coupled to a colorimetric method was adopted for the smartphone-based determination of BPA. The molecularly imprinted polymer (MIP) was prepared via photopolymerization and used as a selective adsorbent material for SPE columns. The solid-phase extraction (SPE) columns with multiple cycles significantly reduced the extraction time to only 30 min. The developed method demonstrates useful sensitivity for BPA (LOD = 30 ppb). Furthermore, BPA migration from plastic packaging was evaluated under different storage conditions, revealing that microwave treatment for 5 min led to BPA release from polycarbonate packaging in juice and basic solutions. The MIP selective extraction/clean-up and smartphone-based optical sensor were successfully applied to BPA standard solutions and complex food samples (e.g., juice and tap water), resulting in reproducible and selective BPA determination (RSD ≤ 6%, n = 3). This rapid and cost-effective method of producing MIPs for BPA offers a promising solution for fast and low-cost sensing for on-site fresh food analysis.

dl-carnitine-based green hydrophobic deep eutectic solvent for the enrichment of bisphenol A in mineral water based on ultrasound-assisted liquid-phase microextraction

A powerful pretreatment technique, ultrasound-assisted dispersive liquid-phase microextraction (USA-DLPME) based on dl-Carnitine-based deep eutectic solvent (DES), has been developed to efficiently enrichment of bisphenol A from mineral water samples. The DES-based USA-DLPME technique demonstrated superior extraction efficiency for bisphenol A compared to established organic solvent-based liquid-liquid extraction techniques. The conditions for the extraction of bisphenol A were predicted using the response surface methodology. The effects of pH (A: 2-10), NaCl concentration (B: 0.2-1.0%w/v), DES volume (C: 30-150 μL), and sonication time (D: 1-5 min) were examined using an experimental design. The extraction recovery of Bisphenol A under optimum conditions was achieved at 99.897% (A = 8, B = 0.4%w/v, C = 120 μL, and D = 5 min). Under these conditions, a wide linear range of 1-600 ng mL-1, an enrichment factor of 81.52, a low detection limit of 0.26 ng mL-1 and a limit of quantification of 0.87 ng mL-1 were obtained. Lastly, the proposed technique was used to accurately and reliably identify bisphenol A in various mineral water samples, yielding relative recoveries in the 92-96% range with RSD≤3%. These findings imply that DESs can be widely and successfully used to extract chemicals from actual materials. DESs are a class of innovative green solvents with the potential to replace organic solvents.

Synthesis and characterization of pH-responsive deep eutectic solvent followed by HPLC for trace determination of bisphenol A in water samples

A microextraction based on pH-responsive deep eutectic solvent combined with high-performance liquid chromatography was developed for the separation, preconcentration, and determination of bisphenol A in water samples. Five deep eutectic solvents were prepared using thymol (hydrogen bond acceptor) and 6-, 8-, 9-, 10-, and 12-carbon carboxylic acids (hydrogen bond donor), and were used as extraction solvent. Herein, by alkalinizing the environment, phase transition takes place, and by adding acid, phase separation and extraction of analytes occur simultaneously. Some important parameters on the extraction such as deep eutectic solvent type, molar ratio of deep eutectic solvent components, deep eutectic solvent volume, potassium hydroxide concentration, hydrochloric acid volume, extraction time, and salt addition were optimized. Under the optimum conditions, intra- and interday precisions of the method based on seven replicate measurements of 10 μg L-1 of bisphenol A in water samples were 2.2% and 4.3%, respectively. The analytical performance of the method showed linearity over the concentration of 0.05-50 μg L-1 with the detection limit of 0.02 μg L-1 . The accuracy of the method was confirmed by spiking different concentrations of bisphenol A in real water samples and obtaining relative recoveries in the range of 92.5%-105.2%.

Magnetic Persimmon Leaf Composite: Preparation and Application in Magnetic Solid-Phase Extraction of Pesticides in Water Samples

In recent years, the utilization of biomass materials for the removal and detection of water pollutants has garnered considerable attention. This study introduces, for the first time, the preparation of Fe3O4/persimmon leaf magnetic biomass composites. The magnetic composites were employed in a magnetic solid-phase extraction method, coupled with gas chromatography-electron capture detection (GC-ECD), for the analysis of four pesticides (trifluralin, triadimefon, permethrin, and fenvalerate) in environmental water samples. The innovative magnetic persimmon leaf composites were synthesized by in situ generation of Fe3O4 nanoparticles through coprecipitation and loaded onto persimmon leaves. These composites exhibit superparamagnetism with a saturation magnetization of 12.8 emu g-1, facilitating rapid phase separation using a magnetic field and reducing the extraction time to 10 min. Desorption can be achieved within 30 s by aspirating 20 times, eliminating the need for time-consuming and labor-intensive experimental steps like filtration and centrifugation. The specific surface area of the magnetic composite adsorbent increased from 1.3279 m2 g-1 for the original persimmon leaf to 5.4688 m2 g-1. The abundant hydroxyl and carboxyl groups on the composites provide ample adsorption sites, resulting in adsorption capacities ranging from 55.056 mg g-1 to 73.095 mg g-1 for the studied pesticides. The composites exhibited extraction recoveries ranging from 80% to 90% for the studied pesticides. Compared to certain previously reported MSPE methods, this approach achieves equivalent or higher extraction recoveries in a shorter operation time, demonstrating enhanced efficiency and convenience. Good linearity of the target analytes was obtained within the range of 0.75-1500 μg L-1, with a determination of coefficient (R2) greater than 0.999. These findings contribute to the use of magnetic persimmon leaf biomass materials as effective and environmentally friendly adsorbents for pollutant determination in water samples.

A green QuEChERS syringe filter based micro-solid phase extraction using hydrophobic natural deep eutectic solvent as immobilized sorbent for simultaneous analysis of five anti-diabetic drugs by HPLC-UV

BACKGROUND

Here, it has been discussed about creating a specific and sustainable analytical technique for monitoring anti-diabetic drugs in order to accurately determine the dosage in patients and reduce side effects, remove them from wastewater (as emerging contaminants), and ultimately abate pharmaceutical pollutants in the environment.

RESULTS

In this research, a green and reproducible Quick Easy Cheap Effective Rugged Safe (QuEChERS) method based on syringe filter based micro-solid phase extraction (SF-μSPE) coupled with HPLC-UV using a green sorbent was developed and optimized for the extraction of five anti-diabetic drugs from wastewater, serum, and plasma real samples. A novel green sorbent composed of a liquid mixture of thymol: menthol ([Thy]:[Men], 1:1) hydrophobic natural deep eutectic solvent (HNADES) and curcumin (Cur) immobilized into the non-toxic and biodegradable polyvinyl alcohol (PVA) electrospun nanofibers' mat was synthesized simply via cheap equipment. Cur was added to enhance the hydrophobicity and functionality of the sorbent. The immobilization process was performed by soaking the mat in the liquid mixture for a specific duration. The correct synthesis and experimental molar ratio of the HNADES components were confirmed by ATR-FTIR and NMR (1H and 13C) spectroscopy. The prepared green sorbent (Cur-HNADES/PVA) was characterized using ATR-FTIR, FE-SEM, EDX/EDX mapping analysis, and water contact angle (WCA) measurement, and it exhibited satisfactory adsorption capacity for the target analytes.

SIGNIFICANCE

Under optimal conditions (pH = 6.0, adsorption cycle = 3, sample volume = 5.0 mL, desorption cycle = 1, type and volume of elution = 80:20 %v/v MeOH/ACN and 500.0 μL), the method was validated in terms of specificity, linear dynamic ranges (LDRs = 0.1-2000.0 μg L-1 and 0.1-1800.0 μg L-1), limits of detection (LODs = 0.03-0.09 μg L-1), and precision (within-day RSDs% = 0.32-1.45% and between-day RSDs% = 0.59-2.03%). Evaluation of the greenness aspects of the proposed method was accomplished using the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) approaches. It is noteworthy that the conducted research represents the first report of the synthesis and application of this novel and green sorbent for the determination of anti-diabetic drugs in the mentioned real samples.

Synthesis of amine-functionalized magnetic porous organic polymers for effective extraction of phenolic endocrine disrupting chemicals

Amine-functionalized porous organic polymers (EDA-POP-PC and EDA-POP-BT) were prepared by post-modification of POP-PC and POP-BT with ethylenediamine (EDA) for the first time. The POP-PC and POP-BT were obtained through Friedel-Crafts acylation reaction of potassium tetraphenylborate with p-phthaloyl chloride (PC) and 1,3,5-benzenetricarbonyl trichloride (BT), respectively. The EDA-POPs exhibited superior adsorption capacity for phenolic endocrine disrupting chemicals (EDCs). After magnetically functionalization, the obtained M-EDA-POP-PC was employed as a magnetic adsorbent for enrichment of phenolic EDCs from real samples prior to high performance liquid chromatography-ultraviolet detection. The current strategy showed low detection limits (S/N = 3) of 0.02-0.07, 0.04-0.08 and 0.04-0.10 ng mL-1 for river water, white peach juice and lychee juice, respectively. The method recoveries were 81.7%-115% with relative standard deviations below 8.6%. The proposed strategy showed good practicality for sensitive determination of phenolic EDCs in real samples.

A new non-enzymatic biosensor for the determination of bisphenol-A

In this study, a new non-enzymatic carbon paste biosensor was developed for the determination of Bisphenol-A (BPA) based on Multiwalled Carbon Nanotube (MWCNT) modified Myoglobin (Mb). The measurement principle of the biosensor was developed based on the inhibition effect of BPA on the heme group of myoglobin in the presence of hydrogen peroxide. With the designed biosensor, measurements were taken in the potential range of (-0.15 V & +0.65 V) using the differential pulse voltammetry (DPV) method in the medium containing K₄[Fe(CN)₆]. The linear range for BPA was determined to be 100-1000 µM. Response time was calculated as 16 s. The limit of detection was set at 89 μM. As a result, it has been proven that MWCNT modified myoglobin based biosensor is an alternative method that can be used for BPA determination, giving very sensitive and fast results.

Development of Magnetic Molecularly Imprinted Polymer Coupled Nanospray Ion Source for Analysis of Cephalosporin Antibiotics in Food Samples

A magnetic molecularly imprinted polymer (MMIP) coupled nanospray ion source was developed for analysis of cephalosporin antibiotics in food samples. MIP coated Fe₃O₄ nanospheres were prepared for magnetic solid-phase extraction (MSPE) of the antibiotics in the extract of samples and then integrated into the nanospray capillary for further desorption and mass spectrometry analysis. The developed device combines the advantages of high extraction efficiency of MSPE, unique selectivity of MIPs, and fast analysis speed of ambient ionization mass spectrometry (AIMS). Five cephalosporin antibiotics in milk, egg, and beef samples were analyzed using the developed methods. High sensitivities with limits of detection (LODs) from 0.3 to 0.5 μg kg^-1 were achieved for cephalosporin antibiotics in milk, egg, and beef samples, respectively. Good linearity, determination coefficient values (R² > 0.992), and precision (RSD < 15%) with recoveries ranging from 72.6% to 115.5% were obtained using the spiked milk, egg, and beef sample matrices.

Smart Portable Device Based on the Utilization of a 2D Disposable Paper Stochastic Sensor for Fast Ultrasensitive Screening of Food Samples for Bisphenols

Since the determination of the high toxicity of bisphenol A, alternative structures for bisphenols have been synthesized, resulting in bisphenols C, E, F, S, and Z. These bisphenols have replaced bisphenol A in plastic bottles, toys, and cans used for preserving food. Later, the toxicity and negative effects of all of these bisphenols on people's health were proven. Therefore, there is a need for a fast ultrasensitive screening method that is able to detect the presence of these bisphenols in any condition directly from food samples. This paper presented a disposable device based on the utilization of a 2D disposable paper stochastic sensor for the fast ultrasensitive screening of food samples for bisphenols A, C, E, F, S, and Z. The 2D disposable sensor was obtained by the deposition of graphene and silver nanolayers on paper using cold plasma. Furthermore, the active side of the sensor was modified using 2,3,7,8,12,13,17,18-octaethyl-21H,23H Mn porphyrin. The limits of quantification of these bisphenols were 1 fmol L^-1 for bisphenols C and E, 10 fmol L^-1 for bisphenols A and F, 10 pmol L^-1 for bisphenol S, and 1 pmol L^-1 for bisphenol Z. The recoveries of these bisphenols in milk, canned fruits, vegetables, and fish were higher than 99.00% with RSD (%) values lower than 1.50%.

Green Synthesis of Molecularly Imprinted Polymers for Dispersive Magnetic Solid-Phase Extraction of Erythrosine B Associated with Smartphone Detection in Food Samples

Monitoring synthetic colorants in foods is important due to their potential toxicity and pathogenicity. We propose here a new and simple method for the extraction and determination of erythrosine B (ERT-B) in food samples. A composite of polydopamine-based molecularly imprinted polymers coating magnetic nanoparticles (Fe₃O₄@PDA@MIP) was synthesized using a green approach and exploited for the magnetic dispersive solid-phase extraction (MDSPE) of ERT-B. Fe₃O₄@PDA@MIP provides a rapid extraction of ERT-B, exhibiting good reusability and preconcentration ability. Moreover, the MIP showed a relatively good imprinting factor (3.0 ± 0.05), demonstrating excellent selectivity against patent blue (an interfering dye) and other food matrix components. The proposed MDSPE was coupled to colorimetric smartphone-based detection that allowed us to obtain similar performances of UV-Vis spectroscopy detection. The smartphone-based optical detection facilitated the determination of ERT-B in the 0.5-10 mg/L range, with a limit of detection of 0.04 mg/L. The developed method was successfully employed to determine ERT-B in food samples (juice, candy, and candied cherries) with good recovery values (82-97%).

Analytical perspective and environmental remediation potentials of magnetic composite nanosorbents

The synthesis and application of magnetic nanosorbents to remove emerging pollutants have been considered the best environmental remediation and sustainability option. Incorporating magnetism shortens the treatment time and allows the sorbent to be recovered quickly using external magnetic with many cycles. The implementation of magnetic solid-phase extraction (MSPE) using magnetic materials of different shapes, sizes, and surface morphology can be a valuable tool in applying materials to prepare analytical samples. In MSPE applications, materials with strong magnetic domain can be used as precursors for constructing magnetic composite as a promising sorbent. This article focuses on the most recent and exceptional applications of magnetic adsorbents for preconcentration and removal purposes. Magnetic adsorbents, such as nanoparticles (NPs), foam, sponges, nanocomposites, hydrogels, and beads with multifunctional attributes have been comprehensively studied in terms of preparation procedures, limitations, advantages, and interactions between pollutants and magnetic composites. The role of magnetic sorbents in sample preparation methods, such as simple solid-phase extraction and microextraction, as well as sorptive extraction using a stir bar, was also examined. The use of magnetic adsorbents with analytical techniques, such as solid-phase extraction and solid-phase microextraction improves the method for preparing samples concerning the influential role of magnetic adsorbents. Towards the end, promising features and future outlook are also directed.

An efficient 3D adsorbent foam based on graphene oxide/AgO nanoparticles for rapid vortex-assisted floating solid phase extraction of bisphenol A in canned food products

In this study, a three-dimensional adsorbent was developed based on graphene oxide/AgO nanoparticles over interconnected nickel foam (GO/AgO@Ni foam) for rapid and efficient vortex assisted floating solid phase extraction of bisphenol A in canned food products prior to high performance liquid chromatography with a fluorescence detector. The analytical techniques scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FT-IR) were used for characterization of the synthetized GO/AgO@Ni foam. The effect of proficiency factors including pH, foam size, vortexing time, salt addition, sample volume, desorption type and volume, and desorption time on the extraction efficiency of bisphenol A were explored through the matrix match method. Under the above experimental conditions, the figures of merit of the method were acquired as LODs (S/N = 3) of 0.18-0.84 μg kg^-1, LOQs of 0.61-2.81 μg kg^-1 (S/N = 10), linear ranges of 0.5-500 μg kg^-1, and enrichment factors of 235.5-244.9. The inter-day precision values (RSD%, n = 7) of 2.5-3.6 and the intra-day precision (%) of (5 days and seven replicates for each day) 2.8-3.8 were achieved for bisphenol A at a concentration of 50 μg kg^-1. The relative recoveries of 94.0% to 99.6% were obtained for the canned food samples.

Imidazole ionic liquid functionalized ZIF-67 molecularly imprinted solid-phase extraction coupled with high performance liquid chromatography for analysis of bisphenol A

An effective method based on an imidazole ionic liquid functionalized ZIF-67 molecularly imprinted solid-phase extractant (ZIF-67@[Bmim][Br]@MIP) coupled with high performance liquid chromatography (HPLC) for the separation/analysis of bisphenol A (BPA) was established. ZIF-67@[Bmim][Br]@MIP was characterized by FTIR, XRD, SEM, TEM and BET. Several important factors, such as pH, amount of extractant, extraction time, and types of eluents were investigated in detail. Under the optimal conditions, the linear range of the method was 0.01-20.00 μg mL^-1, the detection limit was 5.0 ng mL^-1, and the linear correlation was good (R² = 0.9994). The detection of BPA in mineral water bottles, milk cartons and milk tea cups proved that the method was simple and effective, and could be used to separate and analyze BPA in real samples.

Development of a simplified spectrophotometric method for nitrite determination in water samples

A new eco-friendly, rapid, and sensitive spectrophotometric method was developed to determine small quantities of nitrite, based on a diazotization mechanism. In an acidic solution, sulfathiazole was first diazotized with sodium nitrite, followed by adding phosphate buffer to form a yellow-colored compound, which showed maximum absorption at 450 nm, without the need for the addition of coupling agents such as N-(1-naphthyl) ethylenediamine. The effects of reagents amount and the optimal experimental conditions were examined by Central composite design. The simplified method presented a wide linear range of nitrite between 0.091 μg mL^-1 and 1.47 μg mL^-1, a sensitivity of 0.447 Abs mL µg^-1, a determination coefficient of 0.998, and a low limit of detection of 0.053 μg mL^-1. The simplified method was found to be comparable to the Griess method. It was evaluated for the measurements of nitrite using the accuracy profile approach. The validation procedure results established that 80% of the future results would be within the acceptability limit of 10% over the validation domain ranging from 0.174 μg mL^-1 to 1.37 μg mL^-1. The developed method was furtherly applied in the determination of nitrite using a developed paper-based analytical device that detected a nitrite concentration of 3 μg mL^-1 which is considered by the World Health Organization to be the maximal permissible limit of nitrite in drinking water.

A Fluorimetric Method Based On Magnetic Molecularly Imprinted Polymer For Selective Detection Of Chlorferon

In the present work, reusable magnetic molecularly imprinted polymers have been used for the first time as an adsorbent for the determination of chlorferon. Magnetic molecularly imprinted polymers have been used for the selective separation of chlorferon from the solution and sensitive fluorimetric determination has been performed using the native fluorescence of chlorferon. The developed method is rapid and determination of chlorferon was completed in an hour. Limit of detection (LOD) of the method was found to be 0.0027 µM and the linearity of the calibration graph was observed within the range of 0.01-0.36 µM (2.5 - 75 µg L^-1). Adsorption isotherms point out the multilayer adsorption and the heterogeneous distribution of binding sites for imprinted polymer and homogeneous binding site for non-imprinted polymer. The adsorption capacities of imprinted polymer and non-imprinted polymer were calculated as 2.03 μmol g^-1 and 0.96 μmol g^-1, respectively and the imprinting factor was found to be 2.11. The interference effects of some organic compounds and characterization studies were also evaluated. The method has been applied to honey and tap water samples and the recoveries were found to be in the range of 91.3 and 101.1 %.

Application of Molecularly Imprinted Polymers in the Analysis of Waters and Wastewaters

The increase of the global population and shortage of renewable water resources urges the development of possible remedies to improve the quality and reusability of waste and contaminated water supplies. Different water pollutants, such as heavy metals, dyes, pesticides, endocrine disrupting compounds (EDCs), and pharmaceuticals, are produced through continuous technical and industrial developments that are emerging with the increasing population. Molecularly imprinted polymers (MIPs) represent a class of synthetic receptors that can be produced from different types of polymerization reactions between a target template and functional monomer(s), having functional groups specifically interacting with the template; such interactions can be tailored according to the purpose of designing the polymer and based on the nature of the target compounds. The removal of the template using suitable knocking out agents renders a recognition cavity that can specifically rebind to the target template which is the main mechanism of the applicability of MIPs in electrochemical sensors and as solid phase extraction sorbents. MIPs have unique properties in terms of stability, selectivity, and resistance to acids and bases besides being of low cost and simple to prepare; thus, they are excellent materials to be used for water analysis. The current review represents the different applications of MIPs in the past five years for the detection of different classes of water and wastewater contaminants and possible approaches for future applications.

Membrane Emulsification Process as a Method for Obtaining Molecularly Imprinted Polymers

The membrane emulsification process (ME) using a metallic membrane was the first stage for preparing a spherical and monodisperse thermoresponsive molecularly imprinted polymer (TSMIP). In the second step of the preparation, after the ME process, the emulsion of monomers was then polymerized. Additionally, the synthesized TSMIP was fabricated using as a functional monomer N-isopropylacrylamide, which is thermosensitive. This special type of polymer was obtained for the recognition and determination of trace bisphenol A (BPA) in aqueous media. Two types of molecularly imprinted polymers (MIPs) were synthesized using amounts of BPA of 5 wt.% (MIP-2) and 7 wt.% (MIP-1) in the reaction mixtures. Additionally, a non-imprinted polymer (NIP) was also synthesized. Polymer MIP-2 showed thermocontrolled recognition for imprinted molecules and a higher binding capacity than its corresponding non-imprinted polymer and higher than other molecularly imprinted polymer (MIP-1). The best condition for the sorption process was at a temperature of 35 °C, that is, at a temperature close to the phase transition value for poly(N-isopropylacrylamide). Under these conditions, the highest levels of BPA removal from water were achieved and the highest adsorption capacity of MIP-2 was about 0.5 mmol g-1 (about 114.1 mg g-1) and was approximately 20% higher than for MIP-1 and NIP. It was also observed that during the kinetic studies, under these temperature conditions, MIP-2 sorbed BPA faster and with greater efficiency than its non-imprinted analogue.