Synthesis and application of a carbamazepine-imprinted polymer for solid-phase extraction from urine and wastewater

Evaluation of Antibiotics Residues in Milk and Meat Using Different Analytical Methods

Veterinary drugs are pharmacologically and biologically active chemical agents. At present, veterinary drugs are extensively used to prevent and treat animal diseases, to promote animal growth, and to improve the conversion rate of feed. However, the use of veterinary drugs in food-producing animals may leave residues of the parent compounds and/or their metabolites in food products resulting in harmful effects on humans. To ensure food safety, sensitive and effective analytical methods have been developing rapidly. This review describes sample extraction and cleanup methods, and different analytical techniques are used for the determination of veterinary drug residues in milk and meat. Sample extraction methods, such as solvent extraction, liquid-liquid extraction, and cleanup methods such as dispersive solid-phase extraction and immunoaffinity chromatography, were summarized. Different types of analytical methods such as microbial, immunological, biosensor, thin layer chromatography, high-performance liquid chromatography, and liquid chromatography-tandem mass spectrometry were discussed for the analysis of veterinary drug residues in animal-derived foods. Liquid chromatography-tandem mass spectrometry is the most widely used analytical technique for the determination of antibiotic drug residues. This is due to the powerful separation of LC and accurate identification of MS, and LC-MS/MS is more popular in the analysis of veterinary drug residues.

Rapid determination of metanil yellow in turmeric using a molecularly imprinted polymer dispersive solid-phase extraction and visible light spectrophotometry

The present study aimed to develop a sensitive and available method for determining metanil yellow (MY) as an adulterating agent in food samples. Solid-phase extraction was chosen for pre-concentrating metanil yellow prior to its determination using a validated UV-spectrophotometric method. The precipitation polymerization method was applied to synthesize a range of molecularly imprinted polymers (MIPs) for selective extraction of MY. Polymers were characterized by SEM and FTIR and investigated for MY extraction through batch rebinding experiments. The extraction process was optimized in the term of pH, time, capacity, and the desorbing solvent. Results of this study showed the critical role of template/functional monomer ratio in the preparation of the MIPs. The developed MIP solid-phase extraction/UV-spectrophotometric method was employed for determining MY in spiked samples and showed 88.10-92.76% recovery for turmeric samples containing 0.1-10 mg/kg MY. The developed method was shown selective for MY in the presence of another azo dye.

Formation, Analytical Methods, Change Tendency, and Control Strategies of Biogenic Amines in Canned Aquatic Products: A Systematic Review

ABSTRACT

Biogenic amines (BAs) are organic compounds with low molecular weight and can be used as indicators of the quality and safety of canned aquatic products during processing and storage. However, excess of these amines can cause foodborne poisoning. Therefore, the determination, analysis, and prevention of BAs are of great importance. This article focuses on the sources, formation, and pretreatment methods, as well as analytical techniques, change tendency, and control techniques of BAs, with the aim of promoting more appropriate analysis of canned aquatic products to provide a reference for the food industries.

HIGHLIGHTS

Growing Trends in the Efficient and Selective Extraction of Compounds in Complex Matrices Using Molecularly Imprinted Polymers and Their Relevance to Toxicological Analysis

In the world of forensic and clinical toxicology, proper sample preparation is one of the key steps in identification and quantification of drugs of abuse. Traditional extraction methods such as solid-phase extraction and liquid-liquid extraction are often laborious and nonselective for the target analytes being measured. Molecularly imprinted polymers (MIPs) can be synthesized for sample extraction and their versatility allows the polymer to be employed in off-line, benchtop extractions or on/in-line instrument extractions, offering a faster and more selective sample preparation without the risk of interfering matrix effects. This review details the synthesis and applications of MIP materials for the extraction of drug compounds from biological matrices in publications from 1994 to today.

Non-antimicrobial pharmaceuticals can affect the development of antibiotic resistance in hospital wastewater

Within this study, we were interested in the effects of wastewater on the development of antimicrobial resistance. Microorganisms can relatively promptly adapt to evolutionary pressures of the environment, including antibiotics. Therefore, we tested how the adaptability of the model microorganism Salmonella enterica is affected by wastewater full of pharmaceuticals, illicit drugs, and other micropollutants. Wastewater samples had been taken from effluent of hospitals and from wastewater treatment plant (WWTP) Petržalka influent and effluent. In these samples, presence of 38 substances was monitored. The highest concentration was observed in case of tramadol, citalopram, venlafaxine, cotinine, atenolol, valsartan, carbamazepine, azithromycin, and ciprofloxacin. According to this data, we focused also on individual pharmaceutical compounds presented in wastewater samples in elevated concentrations. Effect on resistance development of two pain relief medications (carbamazepine, tramadol), hypotensive medications (atenolol, valsartan), and the nicotine metabolite (cotinine) was also investigated. For this study, we employed concentrations presented in wastewater as well as in urine of patients and/or users. To determine the frequency of mutations leading to ciprofloxacin resistance, we applied the modified Ames test employing the strain Salmonella Typhimurium. Resistance index increased in the case of all wastewater samples from conventional hospitals where we observed a 1.22-1.69-fold increase of mutations leading to ciprofloxacin resistance. Tested compounds caused rise of resistance index in lower concentrations found in wastewater. The most significant increase of resistance index was detected after carbamazepine treatment.

Preparation and evaluation of a porous molecularly imprinted polymer for selective recognition of the antiepileptic drug carbamazepine

A novel and porous molecularly imprinted polymer (PMIP) was synthesized and used as a solid-phase extraction adsorbent for preconcentration of carbamazepine (CBZ) prior to its quantitation by high-performance liquid chromatography (HPLC) in various sample forms (e.g., drinking water, river water, hospital wastewater, and pharmaceuticals). PMIP-CBZ was applied to a polymerization process in which polystyrene spheres were coated with a silica layer. Removal of polystyrene spheres and formation of porous silica facilitated the recovery of CBZ (99.4%) during the extraction process. Site accessibility to the surface of PMIP-CBZ increased the density of high-recognition sites. PMIP-CBZ was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. The key variables influencing the extraction efficiency of PMIP (e.g., adsorbent loading, eluent type, eluent volume, reusability of the adsorbent, and cross-reactivity) were optimized. The optimized protocol was successfully employed to quantify CBZ with limit of detection and limit of quantification as 0.082 and 0.270 ng/mL, respectively (linear detection range: 0.5-250 ng/mL and a relative standard deviation:  < 5%). Use of the PMIP adsorbent resulted in a sensitive and stable method for efficiently quantitation of CBZ from various real sample matrices.

Efficiency comparison of nylon-6-based solid-phase and stir bar sorptive extractors for carbamazepine extraction

Aim: Two approaches based on molecularly imprinted polymers-stir bar sorptive extraction (MIP-SBSE) and -magnetic solid-phase extraction (MIP-MSPE) have been used for extraction of carbamazepine (CBZ) from serum samples. Methodology: In MSPE and SBSE, development was achieved by employing a polycaprolactam coating. The Cecil® chromatographic system equipped with a UV-Vis detector was used for analytical determination of CBZ. Results: The linearity of calibration curves was in the concentration ranges of 0.2–12 and 0.05–12 μg ml-1 for MIP-SBSE and MIP-MSPE, respectively. Conclusion: MIP-MSPE was selected in preference to MIP-SBSE since lower limits of detection were achievable using MIP-MSPE method. The CBZ-MIP-MSPE-HPLC-UV method was successfully applied to CBZ determination in real serum samples of patients receiving CBZ.

Comparative study of substituted poly(4-vinylbenzyl chloride/ethylene glycol dimethacrylate) sorbents for enrichment of selected pharmaceuticals and estrogens from aqueous samples

This study reports the syntheses of four polymeric sorbents based on nucleophilic substitution of Poly(4-vinylbenzylchloride/ethylene glycol dimethacrylate). Polymerization was executed by a simple thermal initiated bulk polymerization procedure. Ground polymer particles were functionalized through reaction with the nucleophiles triethylamine, imidazole, piperidine and pyrrolidine. Mixed-mode phases were characterized by infrared spectroscopy, nitrogen sorption porosimetry and potentiometric titration for determination of chloride content. Furthermore, materials were tested and evaluated for enrichment of seven pharmaceutical and endocrine-disrupting compounds at low ng mL^-1 levels. Results demonstrate that the imidazole modified sorbent led to high and constant recovery rates for nearly all tested compounds. Therefore, this polymer was further tested for applicability with two environmental samples. Spiked tap and river water showed similar results as in evaluation experiments. Moreover, the developed method was validated regarding linearity, repeatability, instrumental limits and stability of analytes according to international guidelines.

Determination of carbamazepine in urine and water samples using amino-functionalized metal-organic framework as sorbent

A stable and porous amino-functionalized zirconium-based metal organic framework (Zr-MOF-NH₂) containing missing linker defects was prepared and fully characterized by FTIR, scanning electron microscopy, powder X-ray diffraction, and BET surface area measurement. The Zr-MOF-NH₂ was then applied as an adsorbent in pipette-tip solid phase extraction (PT-SPE) of carbamazepine. Important parameters affecting extraction efficiency such as pH, sample volume, type and volume of eluent, amount of adsorbent, and number of aspirating/dispensing cycles for sample solution and eluent solvent were investigated and optimized. The best extraction efficiency was obtained when pH of 100 µL of sample solution was adjusted to 7.5 and 5 mg of the sorbent was used. Eluent solvent was 10 µL methanol. Linear dynamic range was found to be between 0.1 and 50 µg L⁻¹ and limit of detection for 10 measurement of blank solution was 0.05 µg L⁻¹. This extraction method was coupled to HPLC and was successfully employed for the determination of carbamazepine in urine and water samples. The strategy combined the advantages of fast and easy operation of PT-SPE with robustness and large adsorption capacity of Zr-MOF-NH₂.

Synthesis and application of selective adsorbent for pirimicarb pesticides in aqueous media using allyl-β-cyclodextrin based binary functional monomers

BACKGROUND

Binary functional monomers, allyl-β-cyclodextrin (allyl-β-CD) and methacrylic acid (MAA) or allyl-β-CD and acrylonitrile (AN), were exploited in a fabrication of molecularly imprinted polymers (MIPs) for selective recognition and large enrichment of pirimicarb from aqueous media.

RESULTS

Special attention was paid to the computational simulation of the imprinting molecular and functional monomers. The morphological characteristics of MIPs made of allyl-β-CD and MAA (M-MAA) were characterised by scanning electron microscopy. The effect of binding capacity of MAA-linked allyl-β-CD MIPs (M-MAA) demonstrated higher efficiency than that of AN-linked allyl-β-CD MIPs (M-AN) when tested in binding specificity. Finally, M-MAA was chosen to run through molecularly imprinted solid-phase extraction (MISPE) to analyse the spiked fresh leafy vegetables of pirimicarb.

CONCLUSION

The present proposed technique is a promising tool for the preparation of the receptors which could recognise pirimicarb pesticide in aqueous media. © 2017 Society of Chemical Industry.

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.

Preparation and study of tramadol imprinted micro-and nanoparticles by precipitation polymerization: microwave irradiation and conventional heating method

In the present work a series of tramadole imprinted micro- and nanoparticles were prepared and study their recognition properties. Methacrylic acid (MAA), as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker and different solvents (chloroform, toluene and acetonitrile (ACN)) were used for the preparation of molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs). Several factors such as template/monomer molar ratio, volume of polymerization solvent, total monomers/solvent volume ratio, polymerization condition (heating or microwave irradiation) were also investigated. Particle size of the polymers, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), rebinding, selectivity tests and release study were applied for evaluation of the polymers. The optimized polymers with smaller particle size and superior binding properties were obtained in acetonitrile under heating method. MIPA4 with a size of 42.6 nm and a binding factor (BF) of 6.79 was selected for selectivity and release tests. The polymerization was not successful in acetonitrile and toluene under microwave irradiation. The MIPA4 could selectively adsorb tramadol, compared to imipramine, naltrexone and gabapentin. The data showed that tramadol release from MIPA4 was significantly slower than that of its non-imprinted polymer. Therefore, MIP nanoparticles with high selectivity, binding capacity and ability to control tramadol release could be obtained in precipitation polymerization with optimized condition.

Study of a molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography for simultaneous determination of trace trichlorfon and monocrotophos residues in vegetables

BACKGROUND

Organophosphate pesticide residues are harmful to human health because of their potential mutagenic and carcinogenic properties. Therefore, it is of great importance to development an accurate and reliable analytical method to prevent their uncontrolled effects on environmental pollution and human health.

RESULTS

This study reports a new method of molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography (MISPE-HPLC) for simultaneous determination of two organophosphate pesticides residues. Two types of molecularly imprinted polymers (MIPs) were prepared using the trichlorfon and monocrotophos as the template molecule, respectively, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The recognition ability and adsorption-desorption dynamic of each imprinted polymer toward the trichlorfon or monocrotophos were characterised. Using the mixture of trichlorfon-MIP and monocrotophos-MIP (20:80, wt/wt) as solid-phase extraction sorbent, the factors affecting the pre-concentration on the analytes and the sensitivity of the MISPE-HPLC method were optimised. Under optimal condition, the linear range was 0.005-1.0 mg L⁻¹. The limit of detection was 4.2 µg g⁻¹ for trichlorfon, and 1.2 ng g⁻¹ for monocrotophos. The peak area precision [Relative standard deviation (RSD)] for three replicates was 2.9-4.5%. The blank rape and cauliflower samples spiked with trichlorfon and monocrotophos at 0.05 and 0.005 µg g⁻¹ levels were extracted and determined by this method with recoveries ranging from 88.5% to 94.2%. Moreover, this method was successfully applied to the quantitative detection of the trichlorfon and monocrotophos residues in leek samples.

CONCLUSION

With good properties of high sensitivity, simple pre-treatment and low cost, this MISPE-HPLC method could provide a new tool for the rapid determination of multi-pesticide residues in the complicated food samples.

Removal of carbamazepine and clofibric acid from water using double templates-molecularly imprinted polymers

A novel double templates-molecularly imprinted polymer (MIP) was prepared by precipitation polymerization using carbamazepine (CBZ) and clofibric acid (CA) as the double templates molecular and 2-vinylpyridine as functional monomer. The equilibrium data of MIP was well described by the Freundlich isotherm model. Two kinetic models were adopted to describe the experimental data, and the pseudo second-order model well-described adsorption of CBZ and CA on the MIP. Adsorption experimental results showed that the MIP had good selectivity and adsorption capacity for CBZ and CA in the presence of competitive compounds compared with non-imprinted polymer, commercial powdered activated carbon, and C18 adsorbents. The feasibility of removing CBZ and CA from water by the MIP was demonstrated using tap water, lake water, and river water.

Application of molecularly imprinted hydrogel for the preparation of lactose-free milk

BACKGROUND

A variety of lactose imprinted hydrogels were prepared and their binding properties were studied in comparison with blank non-imprinted hydrogel. Methacrylamide and ethylene glycol dimethacrylate were used as functional monomer and cross-linker, respectively. Dimethylsulfoxide was also applied as polymerisation solvent.

RESULTS

Different template/monomer ratios were studied and the optimised imprinted hydrogel (MIP₂), with a lactose/methacrylamide ratio of 1:8, was selected in a rebinding test. In Scatchard analysis of MIP₂-lactose interactions, the dissociation constant and maximum binding sites were 0.33 mmol L⁻¹ and 67.76 µmol g⁻¹ hydrogel, respectively. The selectivity of MIP₂ for lactose in aqueous media was also evaluated in comparison with different mono- and disaccharides. The data showed that the affinity of MIP₂ for lactose is significantly higher than other saccharides. The imprinted hydrogel was finally used as a sorbent for separation of lactose from milk.

CONCLUSIONS

The results indicated that MIP₂, as an optimised imprinted hydrogel, can effectively bind lactose and decrease its concentration in milk.

Synthesis of molecularly imprinted polymer as a sorbent for solid phase extraction of citalopram from human serum and urine

This paper describes a new method for the determination of citalopram in biological fluids using molecularly imprinted solid-phase extraction as the sample cleanup technique combined with high performance liquid chromatography. The molecularly imprinted polymers were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinker, chloroform as porogen and citalopram hydrobromide as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of citalopram from human serum and urine. Effective parameters on citalopram retention were studied. The optimal conditions for molecularly imprinted solid-phase extraction consisted of conditioning with 1 mL methanol and 1 mL of deionized water at neutral pH, loading of citalopram sample (50 μg L(-1)) at pH 9.0, washing using 1 mL acetone and elution with 3 × 1 mL of 10 % (v/v) acetic acid in methanol. The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of citalopram. Results from the HPLC analyses showed that the calibration curve of citalopram using MIP from human serum and urine is linear in the ranges of 1-100 and 2-120 μg L(-1) with good precisions (2.5 and 1.5 % for 10.0 μg L(-1)), and recoveries (between 82-86 and 83-85 %), respectively.

Molecularly imprinted nanoparticles prepared by miniemulsion polymerization as selective receptors and new carriers for the sustained release of carbamazepine

Water-compatible imprinted nanoparticles were prepared for carbamazepine as a template and used for the selective extraction and controlled release of carbamazepine. Assay materials and drug delivery carriers were typically used in aqueous environments, so it is generally preferable to prepare solvent-free molecularly imprinted nanoparticles in water using the miniemulsion polymerization method. The present work investigates a bio-analytical strategy generically applicable to imprinted materials for molecular recognition studies, including equilibrium and non-equilibrium binding, and release experiments, increasing the knowledge of the molecular interactions between the template molecules and imprinted nanoparticles. The results showed that the imprinted nanoparticles exhibited a higher binding level and slower release rate than non-imprinted nanoparticles. The selectivity of imprinted nanoparticles for carbamazepine studied in comparison with an analogue compound, oxcarbazepine, the main metabolite of carbamazepine. The recovery and selectivity of carbamazepine in human serum was determined to be 100%, 1.7 times that of oxcarbazepine. The results indicated that carbamazepine-imprinted nanoparticles are appropriate for serum level determination of the drug in therapeutic range. The template to functional monomer ratio as a key factor controlling the recognition and release kinetic mechanism of imprinted nanoparticles is discussed. The imprinted nanoparticles prepared at the appropriate template to functional monomer mole ratio (2:8) exhibited the best drug affinity (5.1 times higher) and a slower drug release rate due to the interaction of carbamazepine with the imprinted cavities within the nanoparticles. Loaded imprinted nanoparticles as drug reservoirs were able to prolong carbamazepine release, in 1% wt sodium dodecyl sulfate aqueous solution, for more than 8 days.

Fabrication of an electrochemical sensor based on computationally designed molecularly imprinted polymers for determination of cyanazine in food samples

A computational approach was used for screening functional monomers and polymerization solvent in the rational design of molecularly imprinted polymers (MIPs). It was based on the comparison of the binding energy of the complexes between the template and functional monomers. On the basis of computational results, acrylamide (AAM) and toluene were selected as functional monomer and polymerization solvent, respectively. The MIP, embedded in the carbon paste electrode, functioned as a selective recognition element and pre-concentrator agent for cyanazine determination by using cathodic stripping voltammetric method. The MIP-CP electrode showed very high recognition ability in comparison with NIP-CPE. Some parameters affecting the sensor response were optimized, and then the calibration curve was plotted. A dynamic linear range of 5.0-1000 nM was obtained. The detection limit of the sensor was calculated as 3.2 nM. This sensor was successfully used for cyanazine determination in food samples.