Pseudo-template molecularly imprinted polymer for selective screening of trace β-lactam antibiotics in river and tap water

Selective extraction and determination of chlorpyrifos residues from aqueous samples using biochar-functionalized molecularly imprinted polymer combined with high-performance liquid chromatography

The concentration of chlorpyrifos (CPF) in aqueous samples was determined using a novel molecularly imprinted dispersive solid-phase extraction (MISPE) approach that was presented in this research. Using a non-covalent molecular imprinting technique, a biochar (BC)-functionalized molecularly imprinted polymers (MIPs) (BC-MIPs) was created. These MIPs were used in dispersive solid-phase extraction (DSPE) in conjunction with high-performance liquid chromatography with photodiode array detection (HPLC-PDA) to detect CPF in aqueous samples with high sensitivity. Using methacrylic acid (MAA) as the monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker, BC-MIPs were created using CPF as a template. By using the suggested dispersive solid-phase extraction (DSPE) approach, the efficiency of the synthesized BC-MIPs granules was evaluated. Analytical performance of the devised DSPE-HPLC-PDA technique was assessed under optimal settings. The optimized parameters included extraction time, aqueous sample pH, desorption time and desorption reagents. Compared with the traditional method, the established method has better selective adsorption capacity, reusability and sensitivity for CPF. The suggested method presented that limit of detection and limit of quantification were 1.0 ng/mL and 4.0 ng/mL, along with excellent linear range (4.0-1500 ng/mL) with coefficients of determination (R2=0.9982). The established method was successfully used to determination CPF in aqueous samples from the Baisha River in Qingdao, with the advantages of accuracy (recoveries: 81.2 %-103.6 %, RSDs≤9.2 %), speed (CPF-BC-MIPs-DSPE time: 75 min; HPLC-PDA time: 12 min), selectivity (imprinting factor: 4.24), and economy (50 mg of adsorbent synthesized using cheap straw and 1 mL of solvents), which partially conform to the current advanced principle of "3S+2A" in analytical chemistry. The BC-MIPs granules shown potential for CPF preconcentration in complicated samples and were effective carriers for the selective adsorption of CPF.

Covalent-Organic Frameworks for Selective and Sensitive Detection of Antibiotics from Water

As the consumption of antibiotics rises, they have generated some negative impacts on organisms and the environment because they are often unable to be effectively degraded, and seeking effective detection methods is currently a challenge. Covalent-organic frameworks (COFs) are new types of crystalline porous crystals created based on the strong covalent interactions between blocked monomers, and COFs demonstrate great potential in the detection of antibiotics from aqueous solutions because of their large surface area, adjustable porosity, recyclability, and predictable structure. This review aims to present state-of-the-art insights into COFs (properties, classification, synthesis methods, and functionalization). The key mechanisms for the detection of antibiotics and the application performance of COFs in the detection of antibiotics from water are also discussed, followed by the challenges and opportunities for COFs in future research.

Nanoscale zero-valent iron alleviate antibiotic resistance risk during managed aquifer recharge (MAR) by regulating denitrifying bacterial network

The frequent occurrence of antibiotics in reclaimed water is concerning, in the case of managed aquifer recharge (MAR), it inevitably hinders further water purification and accelerates the evolutionary resistance in indigenous bacteria. In this study, we constructed two column reactors and nanoscale zero-valent iron (nZVI) amendment was applied for its effects on water quality variation, microbial community succession, and antibiotic resistance genes (ARGs) dissemination, deciphered the underlying mechanism of resistance risk reduction. Results showed that nZVI was oxidized to iron oxides in the sediment column, and total effluent iron concentration was within permissible limits. nZVI enhanced NO3--N removal by 15.5% through enriching denitrifying bacteria and genes, whereas made no effects on oxacillin (OXA) removal. In addition, nZVI exhibited a pivotal impact on ARGs and plasmids decreasing. Network analysis elucidated that the diversity and richness of ARG host declined with nZVI amendment. Denitrifying bacteria play a key role in suppressing horizontal gene transfer (HGT). The underlying mechanisms of inhibited HGT included the downregulated SOS response, the inhibited Type-Ⅳ secretion system and the weakened driving force. This study afforded vital insights into ARG spread control, providing a reference for future applications of nZVI in MAR.

Metal-Chelated Polymeric Nanomaterials for the Removal of Penicillin G Contamination

We developed selective and relatively low-cost metal-chelated nanoparticle systems for the removal of the penicillin G (Pen G) antibiotic, presented for the first time in the literature. In the nanosystem, poly(glycidyl methacrylate) nanoparticles were synthesized by a surfactant-free emulsion polymerization method and covalently bound with a tridentate-chelating ligand, iminodiacetic acid, based on the immobilized metal chelate affinity technique. It was modified with Cu²⁺, a chelating metal, to make Pen G specific. Metal-chelated nanoparticles were characterized by Fourier-transform infrared spectroscopy, energy dispersive spectrometry, zeta dimensional analysis, and scanning electron microscopy technology. Optimization studies of the Pen G removal were conducted. As a result of this study, Pen G removal with the p(GMA)-IDA-Cu²⁺ nanoparticle reached its maximum adsorption capacity of 633.92 mg/g in the short time of 15 min. The Pen G adsorption of p(GMA)-IDA-Cu²⁺ was three times more than that of the p(GMA) nanoparticles and two times more than that of the ampicillin adsorption. In addition, there was no significant decrease in the adsorption capacity of Pen G resulting from the repeated adsorption-desorption process of metal-chelated nanoparticles over five cycles. The metal-chelated nanoparticle had an 84.5% ability to regain its ability to regenerate the product with its regeneration capability, making the widespread use of the system very convenient in terms of reducing cost, an important factor in removal processes.

Template-assisted synthesis of molecularly imprinted polymers for the removal of methyl red from aqueous media

This study entails the synthesis of molecularly imprinted polymers (MIPs) with good selectivity coefficients for azo dye as a potential sorbent material to extract azo dye from polluted aqueous media. A series of MIPs for methyl red (MR) as a template, were synthesized by changing the molar ratio of functional monomers, via precipitation polymerization format of non-covalent approach. Water-soluble functional monomer; acrylic acid (AA) was used to weave the frame work of polymers while ethylene glycol dimethacrylate (EGDMA) was utilized as crosslinking monomer. The impact of different experimental parameters, such as mole ratio of monomer (functional) to crosslinking monomer on the molecular recognition was investigated. The highly efficient and selective MR-MIP was used for the removal of spiked MR dye from different water samples. The selected imprinted polymer, MR1-MIP was able to selectively remove the MR molecules from aqueous media. A significant amount of dye was removed by MR1-MIP from the river water samples with a high degree of removal efficiency i.e. 92.25%. The imprinting factor of 3.75 for MR1-MIP indicated that the high selectivity in terms of adsorption for MR. A minimum loss of only ~ 3.35% in the removal efficiency within ten sequential cycles of adsorption-desorption study evidenced that MR-MIPs could be used as the most cost effective and best sorbent for the removal of MR from polluted water. Furthermore, the structural properties of MR-MIPs were characterized by FTIR and EDX, whereas TGA, SEM and BET were used to describe the thermal, morphological and surface structures of the particles, respectively.

Synthesis of molecularly-imprinted polymers towards a group of amphetamine-type stimulants by reflux precipitation polymerization with a pseudo template

Determination of amphetamine-type drugs (ATSs) in urine and wastewater is a simplified approach for the widespread monitoring of ATSs abuse. To improve the sensitivity of the analytical methods, molecularly imprinted polymers (MIPs) based solid-phase extraction (SPE) pretreatment attracted great attention in this field. Generally, smaller particle sizes and more uniform morphology of the MIPs could provide higher detection sensitivity. Our previous works showed reflux precipitation polymerization (RPP) is a method for synthesizing monodispersed MIPs with small particle size. However, synthesis of uniform spherical MIPs towards a group of targets has never been reported. Therefore, in the present work, MIPs towards a group of ATSs were synthesized via RPP with a pseudo template for the first time. After screening potential pseudo-templates, N-methylphenylethylamine (MPEA) was selected as the optimal pseudo-template. MPEA-MIPs were characterized by scanning electron microscope (SEM), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS) spectra. Adsorption isotherms, adsorption kinetics and selectivity were evaluated, and the experimental results indicated that the MPEA-MIPs possessed good selectivity and adsorption property towards ATSs. After optimization of the MIP-SPE procedure, the MIP-SPE cartridges were then coupled with liquid chromatography and tandem mass spectrometry (LC-MS/MS) for determination of ATSs. The evaluation results showed that MIP-SPE-LC-MS/MS displayed good linearity (R² >0.991) in the linear range (1.0-50.0 µg/L for urine and 0.5-50.0 µg/L for wastewater), and low matrix effect (85-112%). The limit of detection (LOD) was 0.05 -0.29 µg/L, and the accuracy (85-115%) and repeatability (RSD ≤ 15%) were satisfactory at low, medium and high concentrations. To the best of our knowledge, this is the first time that dummy MIPs towards a group of ATSs were synthesized by RPP polymerization, which showed great potential for the detection of ATSs in urine and wastewater.

Dummy Template-Based Molecularly Imprinted Membrane Coating for Rapid Analysis of Malachite Green and Its Metabolic Intermediates in Shrimp and Fish

A novel malachite green molecularly imprinted membrane (MG-MIM) with specific selectivity for malachite green (MG) and leucomalachite green (LMG) was prepared using a hydrophobic glass fiber membrane as the polymer substrate, methyl violet as a template analog, 4-vinyl benzoic acid as the functional monomer, and ethyleneglycol dimethacrylate as the crosslinking agent. MG-MIM and non-imprinted membrane (NIM) were structurally characterized using scanning electron microscopy, surface area analyzer, Fourier-transform infrared spectrometer and synchronous thermal analyzer. The results showed that MG-MIM possessed a fluffier surface, porous and looser structure, and had good thermal stability. Adsorption properties of MG-MIM were investigated under optimal conditions, and adsorption equilibrium was reached in 20 min. The saturated adsorption capacities for MG and LMG were 24.25 ng·cm^-2 and 13.40 ng·cm^-2, and the maximum imprinting factors were 2.41 and 3.20, respectively. Issues such as "template leakage" and "embedding" were resolved. The specific recognition ability for the targets was good and the adsorption capacity was stable even after five cycles. The proposed method was successfully applied for the detection of MG and LMG in real samples, and it showed good linear correlation in the range of 0 to 10.0 μg·L^-1 (R² = 0.9991 and 0.9982), and high detection sensitivity (detection limits of MG and LMG of 0.005 μg/kg and 0.02 μg·kg^-1 in shrimp, and 0.005 μg/kg and 0.02 μg/kg in fish sample). The recoveries and relative standard deviations were in the range of 76.31-93.26% and 0.73-3.72%, respectively. The proposed method provides a simple, efficient and promising alternative for monitoring MG and LMG in aquatic products.

Sensitive 'two-steps' competitive assay for gonadotropin-releasing hormone detection via SPR biosensing and polynorepinephrine-based molecularly imprinted polymer

The work reports an innovative bioassay for the detection of gonadorelin in urine, a gonadotropin-releasing hormone agonist widely used in fertility medicine and to treat hormonal dysfunctions. Gonadorelin is also a synthetic hormone listed by the World Anti-Doping Agency (WADA) and of interest in anti-doping controls. The main novelty relies on the development of a biocompatible, stable, and low-cost biomimetic receptor alternative to classic antibodies. Starting from norepinephrine monomer, a highly selective and sensitive molecularly imprinted polymer (MIP) was developed and optimized for optical real-time and label-free SPR biosensing. The selectivity has been addressed by testing a series of peptides, from high to low similarity, both in terms of molecular weight and primary sequence. Due to the very low molecular weight of gonadorelin (1182 Da), a 'two-steps' competitive assay was developed. Particular attention has been paid to the design of the competitor and its binding affinity constant towards the MIP, being a key step for the success of the competitive strategy. The SPR assay was first optimized in standard conditions and finally applied to untreated urine samples, achieving the sensitivity required by WADA guidelines. The MIP, tested in parallel with a monoclonal antibody, gave comparable results in terms of affinity constants and selectivity towards possible interfering analytes. However, the biomimetic receptor appears clearly superior in terms of sensitivity and reproducibility. This, together with its preparation simplicity, the extremely low-cost of the monomer and its reusability for hundreds of measurements, make polynorepinephrine-based MIPs powerful rivals to immune-based approaches in the near future for similar applications.

Simultaneous elimination of amoxicillin and antibiotic resistance genes in activated sludge process: Contributions of easy-to-biodegrade food

Antibiotics are continuously released into aquatic environments and ecosystems where they accumulate, which increases risks from the transmission of antibiotic resistance genes (ARGs). However, it is difficult to completely remove antibiotics by conventional biological methods, and during such treatment, ARGs may spread via the activated sludge process. Easy-to-biodegrade food have been reported to improve the removal of toxic pollutants, and therefore, this study investigated whether such co-substrates may also decrease the abundance of ARGs and their transferal. This study investigated amoxicillin (AMO) degradation using 0-100 mg/L acetate sodium as co-substrate in a sequencing biological reactor. Proteobacteria, Bacteroidetes, and Actinobacteria were identified as dominant phyla for AMO removal and mineralization. Furthermore, acetate addition increased the abundances of adeF and mdsC as efflux resistance genes, which improved microbial resistance, the coping ability of AMO toxicity, and the repair of the damage from AMO. As a result, acetate addition contributed to almost 100% AMO removal and stabilized the chemical oxygen demand (~20 mg/L) in effluents when the influent AMO fluctuated from 20 to 100 mg/L. Moreover, the total abundance of ARGs decreased by approximately ~30%, and the proportion of the most dominant antibiotic resistance bacteria Proteobacteria decreased by ~9%. The total abundance of plasmids that encode ARGs decreased by as much as ~30%, implying that the ARG spreading risks were alleviated. In summary, easy-to-biodegrade food contributed to the simultaneous elimination of antibiotics and ARGs in an activated sludge process.

Co-substrate addition accelerated amoxicillin degradation and detoxification by up-regulating degradation related enzymes and promoting cell resistance

β-Lactam antibiotics are the most commonly used antibiotics, and are difficult to remove by conventional biological treatments because of their persistent and toxic nature. The addition of co-substrates has been successfully employed to improve the removal of refractory pollutants. So, we hypothesized that the co-substrate strategy would increase antibiotic degradation and benefit microbial survival. In this work, we reported that co-substrate (acetate) addition up-regulated key degrading enzymes and resistance related genes in a model bacteria strain (L. aquatilis) when being treated with 0.055 mM amoxicillin (AMO). β-Lactamase, amidases, transaminase, and amide C-N hydrolase showed increased activation. As a result, AMO removal reached ∼95 %, a ∼60 % increase over the control. Furthermore, the addition of acetate drove the down-stream TCA cycle, which accelerated the detoxification of the intermediates and reduced the microbial inhibition by the antibiotic products to as low as ∼15 %. Besides, the expression levels of genes encoding the efflux pump, penicillin binding proteins, and β-Lactamase were up-regulated, and the inhibition of peptidoglycan biosynthesis was down-regulated. The cell density was enhanced by ∼170 % and showed improved DNA replication. In conclusion, the addition of the co-substrate accelerated AMO degradation and detoxification by up-regulating degrading enzymes and promoting cell resistance.

A model study by using polymeric molecular imprinting nanomaterials for removal of penicillin G

We aimed to develop a molecularly imprinted polymeric systems with using penicillin G as a template molecule for removal of the antibiotic residues from environmental samples. Firstly, Pen-G-imprinted poly (2-hydroxyethyl methacrylate-N-methacryloyl-L-alanine) [p(HEMA-MAAL)] nanopolymers were synthesized by surfactant-free emulsion polymerization method. Then, template molecule (Pen-G) was extracted from nanopolymers. Synthesized nanopolymers were characterized by different methods such as Fourier-transform infrared spectroscopy (FTIR), elemental and zeta-size analysis, scanning electron microscope (SEM), and surface area calculations. Nanopolymers have 60.38 nm average size and 1034.22 m²/g specific surface area. System parameters on Pen-G adsorption onto Pen-G imprint nanopolymers were investigated at different conditions. The specific adsorption value (Q_max) of molecularly impirinted p(HEMA-MAAL) nanopolymers was found 71.91 g/g for Pen-G in 5 mg/mL Pen-G initial concentration. Pen-G adsorption of molecularly imprinted nanopolymers was 15 times more than non-imprinted polymer. It is shown that obtained p(HEMA-MAAL) nanopolymer was a reuseable product which protected its adsorption capacity of 98.9% after 5th adsorption-desorption cycle. In conclusion, we suggest a method to develop a nanostructure, selective, low-cost molecularly imprinted polymeric systems with using penicillin G as a template molecule for removal of the antibiotic residues.

Electrochemical remediation of amoxicillin: detoxification and reduction of antimicrobial activity

Amoxicillin (AMX) is one of the most commonly prescribed antibiotics around the world to treat and prevent several diseases in both human and veterinary medicine. Incomplete removal of AMX during wastewater treatment contributes to its presence in water bodies and drinking water. AMX is an emerging contaminant since its impact on the environment and human health remains uncertain. This contribution was aimed to evaluate the electrochemical oxidation (EO) of AMX using different anodes in tap water, NaCl or Na₂SO₄ solutions and to evaluate the potential toxicity of remaining AMX and its by-products on zebrafish early-life stages. Chemical intermediates generated after EO were determined by mass spectrometry and their resulting antimicrobial activity was evaluated. AMX did not induce significant mortality in zebrafish during extended exposure but affected zebrafish development (increased body length) from 6.25 mg/L to 25 mg/L and inhibited enzymatic biomarkers. Carbon modified with titanium oxide (TiO₂@C) anode achieved complete AMX removal in just a few minutes and efficiency of the supported electrolytes occurred in the following order: 0.1 M NaCl > 0.1 M Na₂SO₄ > 0.01 M NaCl > tap water. The order of potential toxicity to zebrafish early life-stages related to lethal and sublethal effects was as follows: 0.1 M Na₂SO₄ > 0.1 M NaCl >0.01 M NaCl = tap water. Additionally, the EO of AMX using TiO₂@C electrode with 0.01 M NaCl was able to inhibit the antimicrobial activity of AMX, reducing the possibility of developing bacterial resistance.

Hybrid molecularly imprinted polymer for amoxicillin detection

The potential adverse effects of the environmental presence of antibiotics on the ecosystem demands the development of new methods suitable for accurate detection of these micropollutants in various aquatic media. An analytical method exploiting the synergistic effect of a label-free sensing platform combined with a molecularly imprinted polymer (MIP) as robust recognition element could represent an efficient tool for the real-time monitoring of antibiotics. In this work, a hybrid organic-inorganic MIP film (AMO-MIP) selective towards amoxicillin (AMO) was synthesized and integrated with a surface plasmon resonance (SPR) sensor. The film was prepared by sol-gel using methacrylamide (MAAM) as organic functional monomer, tetraethoxysilane (TEOS) as inorganic precursor, and vinyltrimethoxysilane (VTMOS) as coupling agent. The AMO-MIP film characterized with the SPR system demonstrated about 16 times higher binding capacity to AMO than corresponding reference non-imprinted polymer (NIP). AMO-MIP-modified SPR sensors could detect AMO with LoD down to 73 pM and discriminate AMO among structurally similar molecules both in buffer and in tap water. Good reproducibility was achieved for several rebinding-regeneration cycles. The sensor could be stored at room temperature for up to 6 months without losing stability.

Surface restructuring of red mud to produce FeO x (OH) y sites and mesopores for the efficient complexation/adsorption of β-lactam antibiotics

In this work, iron oxide in the red mud (RM) waste was restructured to produce mesopores with surface [FeO _x (OH) _y ] sites for the efficient complexation/adsorption of β-lactam antibiotics. Red mud composed mainly by hematite was restructured by an acid/base process followed by a thermal treatment at 150-450 °C (MRM150, MRM200, MRM300, and MRM450) and fully characterized by Mössbauer, XRD, FTIR, BET, SEM, CHN, and thermogravimetric analyses. The characterization data showed a highly dispersed Fe³⁺ oxyhydroxy phase, which was thermally dehydrated to a mesoporous α-Fe₂O₃ with surface areas in the range of 141-206 m² g^-1. These materials showed high efficiencies (21-29 mg g^-1) for the adsorption of β-lactam antibiotics, amoxicillin, cephalexin, and ceftriaxone, and the data was better fitted by the Langmuir model isotherm (R ² = 0.9993) with monolayer adsorption capacity of ca. 39 mg g^-1 for amoxicillin. Experiments such as competitive adsorption in the presence of phosphate and H₂O₂ decomposition suggested that the β-lactamic antibiotics might be interacting with surface [FeO _x (OH) _y ] species by a complexation process. Moreover, the OH/Fe ratio, BET surface area and porosity indicated that this complexation is occurring especially on [FeO _x (OH) _y ]_surf sites contained in the mesopore space.

A novel surface molecularly imprinted polymer as the solid-phase extraction adsorbent for the selective determination of ampicillin sodium in milk and blood samples

Surface molecularly imprinted polymers (SMIPs) for selective adsorption of ampicillin sodium were synthesized using surface molecular imprinting technique with silica gel as a support. The physical and morphological characteristics of the polymers were investigated by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), elemental analysis and nitrogen adsorption–desorption test. The obtained results showed that the SMIPs displayed great adsorption capacity (13.5 μg/mg), high recognition ability (the imprinted factor is 3.2) and good binding kinetics for ampicillin sodium. Finally, as solid phase extraction adsorbents, the SMIPs coupled with HPLC method were validated and applied for the enrichment, purification and determination of ampicillin sodium in real milk and blood samples. The averages of spiked accuracy ranged from 92.1% to 107.6%. The relative standard deviations of intra- and inter-day precisions were less than 4.6%. This study provides a new and promising method for enriching, extracting and determining ampicillin sodium in complex biological samples.

Preparation of core–shell ion imprinted nanoparticles via photoinitiated polymerization at ambient temperature for dynamic removal of cobalt in aqueous solution

In this work, novel core–shell ion imprinted polymers were firstly synthesized by photoinitiated polymerization (P-IIPs) for the selective separation of Co(ii) in aqueous solution.

Fast HPLC-MS/MS Method for Determining Penicillin Antibiotics in Infant Formulas Using Molecularly Imprinted Solid-Phase Extraction

The dairy cattle may suffer from different infections relatively often, but the inflammation of the mammary gland is very important to the farmer. These infections are frequently treated with penicillin antimicrobial drugs. However, their use may result in the presence of residues in animal products, such as milk powder and/or infant formulas, and it represents a potential risk for consumers. To monitor this, the EU has defined safe maximum residue limits (MRLs) through Commission Regulation (EU) number 37/2010. Although LC-MS is a trustful option for confirmation and quantification of antibiotics, the analysis of real samples with complex matrices frequently implies previous clean-up steps. In this work, precipitation polymerization has been used and different molecularly imprinted polymer (MIP) sorbents were tested and optimized for the fast and simultaneous solid-phase extraction (MISPE) of eight common penicillins (ampicillin, amoxicillin, oxacillin, penicillin G, penicillin V, cloxacillin, dicloxacillin, and nafcillin). The extracts were analyzed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and the applicability of these polymers as sorbents for the extraction of penicillins at MRL levels in milk powder (infant formulas) was proved. The limits of detection and quantification were below the legal tolerances, except for LOQ for oxacillin and cloxacillin.

Preparation of molecularly imprinted polymers based on magnetic carbon nanotubes for determination of sulfamethoxazole in food samples

An efficient approach was developed to synthesize the imprinted magnetic carbon nanotubes nanocomposite and apply for sulfamethoxazole enrichment from milk and honey samples.

Application of molecularly imprinted polymers in wastewater treatment: a review

Molecularly imprinted polymers are synthetic polymers possessing specific cavities designed for target molecules. They are prepared by copolymerization of a cross-linking agent with the complex formed from a template and monomers that have functional groups specifically interacting with the template through covalent or noncovalent bonds. Subsequent removal of the imprint template leaves specific cavities whose shape, size, and functional groups are complementary to the template molecule. Because of their predetermined selectivity, molecularly imprinted polymers (MIPs) can be used as ideal materials in wastewater treatment. Especially, MIP-based composites offer a wide range of potentialities in wastewater treatment. This paper reviews the latest applications of MIPs in wastewater treatment, highlights the development of MIP-based composites in wastewater, and offers suggestions for future success in the field of MIPs.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Systematic screening of common wastewater-marking pharmaceuticals in urban aquatic environments: implications for environmental risk control

In this report, we refer to pharmaceuticals that are widespread in the urban aquatic environment and that mainly originate from wastewater treatment plants or non-point source sewage as "wastewater-marking pharmaceuticals" (WWMPs). To some extent, they reflect the condition or trend of water contamination and also contribute to aquatic environmental risk assessment. The method reported here for screening typical WWMPs was proposed based on academic concerns about them and their concentrations present in the urban aquatic environment, as well as their properties of accumulation, persistence, eco-toxicity and related environmental risks caused by them. The screening system consisted of an initial screening system and a further screening system. In the former, pharmaceuticals were categorised into different evaluation levels, and in the latter, each pharmaceutical was given a normalised final evaluation score, which was the sum of every score for its properties of accumulation, persistence, eco-toxicity and environmental risk in the aquatic environment. The system was applied to 126 pharmaceuticals frequently detected in the aquatic environment. In the initial screening procedure, five pharmaceuticals were classified into the "high" category, 16 pharmaceuticals into the "medium" category, 15 pharmaceuticals into the "low" category and 90 pharmaceuticals into the "very low" category. Subsequently, further screening were conducted on 36 pharmaceuticals considered as being of "high", "medium" and "low" categories in the former system. We identified 7 pharmaceuticals with final evaluation scores of 1-10, 10 pharmaceuticals with scores of 11-15, 15 pharmaceuticals with scores from 16 to 20 and 4 pharmaceuticals with scores above 21. The results showed that this screening system could contribute to the effective selection of target WWMPs, which would be important for spatial-temporal dynamics, transference and pollution control of pharmaceuticals in the urban aquatic environment. However, there remains a number of pharmaceutical parameters with measured data gaps, such as organic carbon adsorption coefficients and bioconcentration factors, which, if filled, would improve the accuracy of the screening system.

Application of molecularly imprinted polymers in food analysis: clean-up and chromatographic improvements

Several natural and synthetic substances have been monitored in analytical laboratories worldwide to ensure food safety. Multiple residue detection (i.e., detection of multiple analytes in a single sample or matrix) is a main weakness of existing analytical methods, when fast and reliable results are required. Multianalyte approaches may save time and money in the food industry, and more importantly, they allow the quick release of food products into the marketplace. In addition, multianalyte approaches notably decrease the time required between sampling and analysis to meet legal requirements. However, to achieve analytical success, it is necessary to develop thorough clean-up procedures to extract analytes from the matrix. In addition, good chromatographic separation methods are also necessary to distinguish closely related analytes. Molecular imprinting technology (MIT) is an emerging, powerful tool for sample extraction and chromatography. First used for solid-phase extraction, molecularly imprinted polymers (MIPs) are also effective chromatographic phases for the separation of isomers and structurally related molecules. In recent years, a number of analytical methods utilising MIT have been applied for the analysis of residues in food, and existing methodologies have been improved. This review article describes the latest applications of MIT in the development of methodologies to monitor the presence of residues of veterinary products in foodstuff.

The opposite impacts of Cu and Mg cations on dissolved organic matter-ofloxacin interaction

Dialysis equilibrium system was applied to investigate the roles of Cu(II) and Mg(II) on DOM-ofloxacin (OFL) interaction. The binding behavior of both cations and OFL were studied. The introduction of Cu(II) increased DOM-OFL interaction, while Mg(II) decreased DOM-OFL binding. Cu(II) binding to DOM was also increased by OFL, while Mg(II) binding was decreased by OFL. The change in OFL binding amount in the absence and presence of cations (ΔC(b)) was calculated and compared with cation binding (C(b)(m)). ΔC(b)/C(b)(m) was in the range of 1-3 for Cu(II) depending on the applied Cu concentration. Two ternary complexes of DOM-OFL-Cu and DOM-Cu-OFL were proposed. For Mg(II), ΔC(b)/C(b)(m) was around -1 at Mg(II) concentrations lower than 1 mM, but decreased up to -5 with increasing Mg(II) concentration. The competitive effect of Mg(II) to OFL was thus proposed. FTIR spectra were collected for mechanistic discussion.

Removal of water-soluble acid dyes from water environment using a novel magnetic molecularly imprinted polymer

Novel magnetic and hydrophilic molecularly imprinted polymers (mag-MIPs) were prepared by an inverse emulsion-suspension polymerization to remove water-soluble acid dyes from contaminated water with 1-(α-methyl acrylate)-3-methylimidazolium bromide (1-MA-3MI-Br) being utilized as a new functional monomer. The thermal stability, chemical structure and magnetic property of the 1-MA-3MI-Br-mag-MIPs were characterized by the thermal-gravimetric analyzer (TGA), Fourier transform infrared spectrometer (FT-IR) and vibrating sample magnetometer (VSM), respectively. Moreover, effect of concentration and pH value of water-soluble acid dye solutions was optimized. Compared with the methyl acrylic acid and 4-vinylpyridine modified mag-MIPs, the 1-MA-3MI-Br-mag-MIPs showed enhanced removal efficiency. Kinetic studies depicted that the adsorption process on 1-MA-3MI-Br-mag-MIPs followed pseudo-second-order rate mechanism. Investigation results of 5 times removal-regeneration cycles by employing the 1-MA-3MI-Br-mag-MIPs showed that the resulting material was with high stability.

Identification of new minor metabolites of penicillin G in human serum by multiple-stage tandem mass spectrometry

Liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) were applied to characterize drug metabolites. Although these two methods have overcome the identification and structural characterization of metabolites analysis, they remain time-consuming processes. In this study, a novel multiple-stage tandem mass spectrometric method (MS(n) ) was evaluated for identification and characterization of new minor metabolism profiling of penicillin G, one of the β-lactam antibiotics, in human serum. Seven minor metabolites including five phase I metabolites and two phase II metabolites of penicillin G were identified by using data-dependent LC/MS(n) screening in one chromatographic run. The accuracy masses of seven identified metabolites of penicillin G were also confirmed by mass spectral calibration software (MassWorks™). The proposed data-dependent LC/MS(n) method is a powerful tool to provide large amounts of the necessary structural information to characterize minor metabolite in metabolism profiling.

Dummy molecularly imprinted polymer for selective screening of trace bisphenols in river

Bisphenols (BPs) are potential endocrine-disrupting chemicals that may adversely affect human health and wildlife. The complexity of matrix encountered in real-world samples renders screening of trace BPs a formidable challenge. The present study highlighted the potential of molecularly imprinted solid-phase extraction (MISPE) for selective detection of trace bisphenols and their halogenated analogues in surface water. The template bleeding was observed at parts-per-billion levels, deteriorating the accuracy and precision of BPs quantification. To surmount this problem, a dummy MISPE strategy was proposed, in which bisphenol E (BPE) was selected as a dummy template for molecularly imprinted polymer (MIP) synthesis. Coupling this MISPE strategy with chromatographic analysis, a dummy MISPE-HPLC method was established. The linearity, precision, limit of detection (LOD) and recovery were then validated. The linearity of the calibration curve for each BP was observed over the range of 20-2000 ng L-1 (r > 0.998). LOD for each bisphenol was measured as low as 2.5-5.0 ng L-1. This technique was applied to simultaneous screening of BPs in the Qinghe River, and five bisphenols were found within the concentration range of 0-224 ng L-1 in river samples. The designed dummy MIP was superior to the commercial sorbents with regard to the selectivity, cross-reactivity, matrix removal efficiency and reusability. These merits enabled the applications of dummy MISPE for selective extraction and sensitive screening of BPs in environmental water samples. This method also provided a promising tool for monitoring the occurrence, distribution and fate of BPs in surface water.