Template Molecule Research Articles

Melamine‐imprinted quartz crystal microbalance sensor for its detection in milk

AbstractA unique and selective molecularly imprinted polymer (MIP) was fabricated to detect melamine using a quartz crystal microbalance (QCM) surface. The MIP was synthesized by sol–gel technique utilizing 3‐(trimethoxysilyl) propyl methacrylate (TMSPMA) as the functional monomer bearing the methacrylate head group. To identify the melamine, we applied a coating of the as‐synthesized MIP over the silicon crystal of the quartz crystal microbalance (QCM) detector. High‐affinity adsorption of template molecules from the aqueous solution is the basis of the detection. Adsorption experiments performed in real‐time on MIP surfaces indicate that melamine forms strong bonds with its template molecule. We have evaluated the MIP surface using contact angle, BET, RAMAN and AFM investigations regarding wettability, reactivity, surface area, and smoothness. The real‐time adsorption experiments of template molecules on the MIP substrate reveal enhanced attachments with MIP, whereas the NIP demonstrates no interactions with the template molecules. Melamine detection in tainted milk samples further validated the MIP QCM sensor effectiveness. Melamine at a concentration ranging from 1–20 mg/L is tested. Findings conclude that the polymerization method and the QCM nanosensor for selective melamine detection were adequate substitutes for the technologies currently used for detecting melamine.

A novel molecularly imprinted electrochemical sensor from poly (3, 4-ethylenedioxythiophene)/chitosan for selective and sensitive detection of levofloxacin

The improper usage of levofloxacin (LEV) endangers both environmental safety and human public health. Therefore, trace analysis and detection of LEV have extraordinary significance. In this paper, a novel molecularly imprinted polymer (MIP) electrochemical sensor was developed for the specific determination of LEV by electrochemical polymerization of o-phenylenediamine (o-PD) using poly(3,4-ethylenedioxythiophene)/chitosan (PEDOT/CS) with a porous structure and rich functional groups as a carrier and LEV as a template molecule. The morphology, structure and properties of the modified materials were analyzed and studied. The result showed that the electron transfer rate and the electroactive strength of the electrode surface are greatly improved by the interconnection of PEDOT and CS. Meanwhile, PEDOT/CS was assembled by imprinting with o-PD through non-covalent bonding, which offered more specific recognition sites and a larger surface area for the detection of LEV and effectively attracted LEV through intermolecular association. Under the optimized conditions, MIP/PEDOT/CS/GCE showed good detection performance for LEV in a wide linear range of 0.0019– 1000 μM, with a limit of detection (LOD, S/N = 3) of 0.4 nM. Furthermore, the sensor has good stability and selectivity, and exhibits excellent capabilities in the microanalysis of various real samples.

Electrochemical Sensor for Levetiracetam Therapeutic Monitoring in Biological Fluid Utilizing Molecular Imprinted Polymer Electrografted onto Pencil Graphite Electrode

A newly-developed, molecularly imprinted copolymer (MIP) has been constructed and effectively employed as a highly-selective recognition element for anti-epileptic drug; levetiracetam (LEV) in low concentrations. The MIP sensor for LEV was fabricated via in situ electrochemical co-polymerization of o-phenylenediamine (o-PD) and L-dopa as functional monomers in the presence of LEV as a template molecule onto pencil graphite electrode. UV-Spectrophotometric technique was carried out to inspect and assess the template-monomer binding interactions. The molecularly imprinted copolymer’s structure and morphology were examined through X-ray photoelectron spectroscopy and scanning electron microscopy. Multiple experimental parameters have been investigated and optimized in order to improve the sensor’s responsiveness towards LEV. Utilizing differential pulse voltammetry, quantitative measurements of MIP-based LEV detection were achieved indirectly by measuring the decrease in response of redox probe upon binding of LEV to the 3D cavities of MIP in phosphate buffer saline pH 7.40. The method’s validation was performed in accordance with ICH guidelines. The fabricated sensor showed a linear voltammetric response with a linearity range of (1.5 × 10–12–1.0 × 10–10 M). The sensor was able to effectively detect LEV in spiked artificial human saliva.

Alkane molecularly imprinted nanofiber membranes used to enhance the diesel degradation process

AbstractCombining molecular imprinting technology with electrostatic spinning technology, a molecularly imprinted nanofiber membrane material with memory and recognition of specific imprinted molecules is thus produced. It has the advantages of high efficiency, reusability, easy amplification, and simple operation. In this study, alkane molecularly imprinted nanofibrous membranes are prepared as a carrier for immobilize Bacillus cereus LY‐1 for the degradation of diesel in oil–water system. The adsorption capacity of the molecularly imprinted material for diesel oil with n‐decyl alcohol as the template molecule reach 120.25 mg g−1, the adsorption capacity of alkane molecularly imprint nanofiber membrane prepared using polyvinyl alcohol (PVA) as the membrane substrate material is 41.37 mg g−1. After 4 days, the immobilized LY‐1 cells eliminate roughly 80.7% of the diesel at a starting concentration of 3 g L−1. The results show that imprinted structures in MINM enhance degradation by loaded microorganisms.

Abstract 949: A single stranded DNA library preparation workflow used for hybridization capture based WES assay showed superior uniformity

Abstract Introduction: In many instances in Precision Oncology Medicine fragmented DNA from formalin-fixed paraffin-embedded (FFPE) samples is the only option. The majority of such degradedsamples need to be sequenced using next generation sequencing (NGS) [1]. Standardizedguidelines highlight that a minimum of 500 × coverage depth is required for tissue analyses [2].However, coverage isn’t the only metric required for a successful NGS analysis. Highly uniformDNA libraries allow clinical labs to generate more hits from their screens, saving both time andmoney across the course of diagnosis therefore ultimately benefits patient care. The commerciallyavailable single stranded DNA library prep kit tested in this study renders all input moleculessingle-stranded before ligation therefore it recovers template molecules containing DNA nicks andlabile lesions thus maximizing library complexity. Method: 10 solid tumor FFPE derived DNA samples went through three different NGS workflows:100ng of DNA input in an amplicon-based assay 325 gene panel (Assay A), 60ng input for a 500gene mechanical sheared-based double strand DNA library preparation with hybridization captureassay (~500 gene panel, Assay B), 50ng and 10ng input for a enzymatic shear-based singlestranded DNA library preparation with hybridization capture assay (WES with 1000+ enhancedgene content, Assay C). Data from assays A and C was processed with in-house bioinformaticpipeline, while Assay B’s data was processed with a commercially available bioinformatic pipelinethat was bundled with the assay. NGS QC metrics were compared across the three datasets. Results: This novel single stranded DNA library preparation with hybridization capture workflowshowed superior QC metrics compared to the other two workflows, especially on coverageuniformity and percent target above 100X, with as low as 10ng input. Conclusion: Employing a novel commercially available DNA library preparation workflow in anNGS assay, NeoGenomics was able to rescue poor quality samples that had previously failed tomeet our internal uniformity metric on other NGS assays and generate robust and reportableresults with as low as 10ng DNA input.[1] Nagahashi et al., J Surg Res. 2017 Dec; 220: 125-132.[2] Cappello et al., J Pers Med. 2022 May; 12(5): 750. Citation Format: Jieying Chu, Rachel Schell, Faqiang Wu, Michal Krawczyk, Daniel Whang, Segun Jung, Hyunjun Nam, Kenneth B. Thomas, Fernando J. Lopez-Diaz, Vincent Funari, Julie A. Mayer, Shashi Kulkarni, Jiannan Guo, Steven P. Lau-Rivera. A single stranded DNA library preparation workflow used for hybridization capture based WES assay showed superior uniformity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 949.

Abstract 5014: Analytical validation of a complete system for detection and characterization of genomic aberrations in circulating tumor DNA

Abstract Cell-free DNA (cfDNA) fragments are readily detected at a low concentration in the human blood stream. In healthy patients cfDNA is primarily derived from apoptosis of hematopoietic cells. In cancer patients circulating DNA derived from tumor cells (ctDNA) undergoing apoptosis, shedding, and necrosis contribute to total cfDNA. Next generation sequencing (NGS) of cfDNA isolated from patient plasma can be used to fully characterize cancer driven changes in the tumor DNA including the relative contribution of cfDNA, single nucleotide variants (SNVs), small insertions and deletions (Indels), larger deletions, regions of amplified DNA, and structural rearrangements. Frontage has developed a complete lab system for analysis of circulating cfDNA including automated sample extraction, preparation and sequencing of libraries targeting exon sequences of 293 oncology-related genes, and a bioinformatic reporting system. The Frontage sample extraction process uses a post-extraction size selection step to remove high molecular weight DNA derived from lysed blood cells in the plasma sample to increase the sensitivity of detection of ctDNA. The NGS platform couples hybridization-based selection of genomic DNA fragments derived from protein-coding exons with deep sequencing to ~4,000X gross coverage on the NextSeq 2000. The bioinformatic pipeline integrates unique molecular barcode-based generation of consensus reads for each template molecule, somatic variant calling with GATK Mutect2 and FreeBayes, and removal of false positive variants by comparison to a 60 samples healthy patient data set. Analytical validation was performed for each component of the system. For verification of the sample extraction process, cfDNA was extracted in duplicate from four lots of pooled K2 EDTA plasma of healthy patients as well as individual K2 EDTA plasma of colorectal cancer (CRC) patients in four independent extraction runs. The mean yields of cfDNA from healthy samples ranged from 2.3 - 4.2 nanograms per ml plasma and all 32 of the isolated cfDNA aliquots from healthy patient plasma showed a prominent peak around 167 nt with minimal contamination from high molecular weight DNA. For validation of the NGS and bioinformatics platform a set of 8 different reference cfDNAs were processed through four independent runs of library preparation, sequencing, and analysis. For each of the validation runs, greater than 97% of 208 SNVs and Indels with expected allele frequencies (AF) between 2-3% were detected by the platform with higher levels of accuracy for variants at above 3% AF. Two or less false positive variants per run were detected out of 278,000 nucleotides of verified non-mutated sequence that overlapped with the 293 gene panel. Four known DNA amplification events were detected in each of the validation runs. Data from characterization of CRC and other clinical samples with the system will be presented. Citation Format: Ericca Stamper, Weiming Shen, Aman Pruthi, Casey Nagel, Marcin Piechota, Katarzyna Tomala, Qi Wei, David Willoughby. Analytical validation of a complete system for detection and characterization of genomic aberrations in circulating tumor DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5014.

Electrochemical-assisted synthesis of molecularly imprinted graphene oxide/magnetite for highly selective enantiomer separation

Enantiomeric compounds have been reported to exhibit different biological and pharmacological activities. MIP-GO/Fe3O4 has been synthesized with L-glutamic acid (L-Glu) as template molecules and developed to separate amino acids enantiomeric compounds (AAs) especially for DL-glutamic acid (DL-Glu). The MIP-GO/Fe3O4 adsorbent material was synthesized in several stages, namely electrochemically synthesizing GO, co-precipitation for GO/Fe3O4, and surface imprinting polymerization to obtain MIP-GO/Fe3O4. The characterization results of MIP-GO/Fe3O4 show that the composite system has been successfully created with saturation magnetization (Ms) values of 49.37 emu/g. Adsorption tests are carried out on the racemic mixture of DL-Glu and show that the material worked effectively and selectively to separate D- and L-Glu with a %ee value of 97.86 % and an adsorption capacity for L of 9.9 mg g−1 on optimum conditions. In addition, the adsorbent developed shows good reusability values with a decreasing performance of no more than 2.0 % after 10-time use cycles and is easily separated in less than 15 s. This research contributes to developing advanced materials with extraordinary selectivity and efficiency, paving the way for advances in enantiomer separation technology.

Determination of pesticide residue in soil samples by molecularly imprinted solid-phase extraction method

Abstract Porous molecularly imprinted polymer (MIP) microspheres were synthesized via iniferter-suspension polymerization method, employing lenacil (LA) as the template molecule and methacrylic acid (MAA) as the functional monomer. The host–guest complexes formed using LA and MAA were characterized by hydrogen nuclear magnetic resonance and ultraviolet–visible absorption spectroscopy. The obtained results showed that the interaction between LA and MAA mainly relied on hydrogen bonding. The surface morphologies and chemical structures of the MIPs were characterized by scanning electron microscopy. MIPs were spherical in shape with a relatively regular sphericity, rough surface structure, and numerous small holes, which significantly reduced the mass transfer resistance of the template molecules and exhibited excellent recognition performance for template molecules. In addition, soil samples were pretreated with solid-phase extraction columns molecularly imprinted with LA, and analyzed by high-performance liquid chromatography. The recoveries of LA, bromacil, and terbacil were up to 89.65%, 53.17%, and 44.63%, respectively. The developed method showed a minimum detection limit of 10–50 µg·mL−1. In view of the continuous increase of public requirements for pesticide residue detection, a versatile pretreatment method was developed that is green, rapid, simple, and can be miniaturized.

Study on the Selectivity of Molecular Imprinting Materials Determined through Hydrogen Bonding on Template Molecular Structures of Flavonoids.

Molecular imprinting technology is widely used for the specific identification of compounds, but the selective recognition mechanisms of the same compounds still need to be further studied. Based on differences in hydrogen bond size and orientation, molecularly imprinted polymers (MIPs) were designed to adsorb flavonols with the same parent core and different hydroxyl groups. A surface-imprinted material was designed with silicon dioxide as the carrier, myricetin as the template molecule, and methacrylic acid (MAA) as the functional monomer. Scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area (BET) analyses, Fourier-transform infrared spectroscopy (FT-IR), and other characterization experiments were carried out. The intrinsic mechanism of the MIPs was also explored. The MIPs showed good adsorption of myricetin and other flavonoids through hydrogen bonding and steric hindrance. The adsorption capacity was 3.12-9.04 mg/g, and the imprinting factor was 1.78-3.37. Flavonoids with different hydroxyl groups in different numbers and directions had different hydrogen bond strengths with functional monomers. R2, R4, and R1 on 2-phenylchromogenone had stronger electronegativity, and the hydroxyl group was also more likely to form and have stronger hydrogen bonds. The hydroxyl negativity and the degree of steric hindrance of flavonoids played a major role in the recognition of molecularly imprinted materials. This study is of great significance for the synthesis of and selection of templates for analogous molecular imprinting materials.

Renin imprinted Poly(methyldopa) for biomarker detection and disease therapy

Conventional molecularly imprinted polymers (MIPs) perform their functions principally depended on their three dimensional (3D) imprinted cavities (recognition sites) of templates. Here, retaining the function of recognition sites resulted from the imprinting of template molecules, the role of functional monomers is explored and expanded. Briefly, a class of dual-functional renin imprinted poly(methyldopa) (RMIP) is prepared, consisting of a drug-type function monomer (methyldopa, clinical high blood pressure drug) and a corresponding disease biomarker (renin, biomarker for high blood pressure disease). To boost target-to-receptor binding ratio and sensitivity, the microstructure of recognition sites is beforehand calculated and designed by Density Functional Theory calculations, and the whole interfacial structure, property and thickness of RMIP film is regulated by adjusting the polymerization techniques. The dual-functional applications of RMIP for biomarker detection and disease therapy in vivo is explored. Such RMIP-based biosensors achieves highly sensitive biomarker detection, where the LODs reaches down to 1.31 × 10−6 and 1.26 × 10−6 ng mL−1 for electrochemical and chemical polymers, respectively, and the application for disease therapy in vivo has been verified where displays the obviously decreased blood pressure values of mice. No acute and long-term toxicity is found from the pathological slices, declaring the promising clinical application potential of such engineered RMIP nanostructure.

Designing Molecularly Imprinted Polymer-Modified Boron-Doped Diamond Electrodes for Highly Selective Electrochemical Drug Sensors.

Drug detection in biological solutions is essential in studying the pharmacokinetics of the body. Electrochemical detection is an accurate and rapid method, but measuring multiple drugs that react at similar potentials is challenging. Herein, we developed an electrochemical sensor using a boron-doped diamond (BDD) electrode modified with a molecularly imprinted polymer (MIP) to provide specificity in drug sensing. The MIP is a polymer material designed to recognize and capture template molecules, enabling the selective detection of target molecules. In this study, we selected the anticancer drug doxorubicin (DOX) as the template molecule. In the electrochemical measurements using an unmodified BDD, the DOX reduction was observed at approximately -0.5 V (vs Ag/AgCl). Other drugs, i.e., mitomycin C or clonazepam (CZP), also underwent a reduction reaction at a similar potential to that of DOX, when using the unmodified BDD, which rendered the accurate quantification of DOX in a mixture challenging. Similar measurements conducted in PBS using the MIP-BDD only resulted in a DOX reduction current, with no reduction reaction observed in the presence of mitomycin C and CZP. These results suggest that the MIP, whose template molecule is DOX, inhibits the reduction of other drugs on the electrode surface. Selective DOX measurement using the MIP-BDD was also possible in human plasma, and the respective limits of detection of DOX in PBS and human plasma were 32.10 and 16.61 nM. The MIP-BDD was durable for use in six repeated measurements, and MIP-BDD may be applicable as an electrochemical sensor for application in therapeutic drug monitoring.

Risk mitigation strategy and mechanism analysis of neonicotinoid pesticides on earthworms

Neonicotinoid insecticides (NNIs) are a new class of widely used insecticides with certain risks to non-target organisms, like earthworms. The gray correlation method was used to calculate the comprehensive risk effect value of acute toxicity (LC50) and bioaccumulation (logKow) of NNIs on earthworms. A comprehensive effects three-dimensional quantitative structure–activity relationship (3D-QSAR) model was constructed, using NNIs molecular structures and the comprehensive effect value as the independent and dependent variables, respectively. One of the representatives guadipyr (GUA) was selected as the template molecule for the molecular design and modification. A total of 63 NNIs alternatives were designed with a reduced comprehensive value higher than 10%, and as high as 42%. After screening, 15 NNIs alternatives were screened with decreased acute toxicity to earthworms, bioaccumulation effects and improved functional property. The calculated primary acute risk quotient of earthworms shows that the designed NNIs alternatives have lower earthworm risks (reduction of 70.48–99.99%). Results also found that the electronic, geometric and topological parameters of NNIs are the key descriptors that affect NNIs alternatives' toxicity. The number of hydrophobic interaction amino acid residues in NNIs molecules also contributes to the acute toxicity and the bioaccumulation of NNIs alternatives on earthworms. This study aims to design and screen functionally improved and environmentally friendly NNIs alternatives that have low risk to earthworms and provide theoretical methods and new ideas for the risk control and development of pesticides represented by NNIs.

Synthesis of multi-template molecularly imprinted polymers (MT-MIPs) for isolating ethyl para-methoxycinnamate and ethyl cinnamate from Kaempferia galanga L., extract with methacrylic acid as functional monomer

Abstract Kaempferia galanga L. extract contains ethyl p-methoxycinnamate (EPMC) and ethyl cinnamate (EC), which have several pharmacological activities. EPMC and EC have been successfully isolated, but the %yield was low. Therefore, developing an isolation method to increase the %yield result of EPMC and EC is essential. The molecularly imprinted polymers have been applied to separate lot of active compounds from natural products with excellent results. MIP synthesis is usually performed using a single template with high selectivity for the target analyte but only detect single chemical compounds. Hence, this study synthesized multi-template molecularly imprinted polymers (MT-MIPs) for isolating EPMC and EC simultaneously using methacrylic acid as a functional monomer and ethylene glycol dimethacrylate or trimethyl propane trimethacrylate (TRIM) as a crosslinker. The study results indicate that MT-MIP produced with TRIM is more effective in separating EPMC and EC simultaneously in K. galanga L. extracts. However, the yields of EPMC and EC were still low. The yields of EPMC and EC in n-hexane extracts were 1.557 and 1.929%, with purity of 66.330 and 61.510%, respectively. Further research is necessary to determine the ideal functional monomer and its ratio to template molecules to obtain the excellent selectivity of the MT-MIPs used for simultaneously isolating EPMC and EC.

A Dimode Scattering Method for Ultratrace Dinitrofuran Detection with Nanopalladium Molecularly Imprinted Polymer Nanocatalytic Probe.

With four nanoparticles as the nanomatrix, dinotefuran (DNF) as the template molecule, N-isopropylacrylamide as the functional monomer, trimethylolpropane and trimethacrylate as the cross-linker, four nanosurface molecularly imprinted polymer (MIP) bifunctional probes were prepared by microwave synthesis. It was found that palladium nanosurface MIP (Pd@MIP) not only recognized DNF but also had the strongest catalytic effect on the new nanogold indicator reaction of acrylic acid-HAuCl4, which was evaluated quickly with the slope procedure developed by us. The generated gold nanoparticles (AuNPs) not only possessed the resonance Rayleigh scattering (RRS) effect but also strong surface-enhanced Raman scattering (SERS) activity. The combination of Pd@MIP with DNF enhanced the catalytic effect by coupling the nanosurface electrons with π-electrons, thus enhancing both scattering signals. A new Pd@MIP nanoprobe catalytic-SERS/RRS dual-mode analytical platform was developed for the specific and sensitive detection of DNF. The linear ranges of the SERS and RRS methods were 0.075-0.75 and 0.1-0.75 nmol/L, and the limits of detection were 0.03 and 0.06 nmol/L, respectively. The standard deviations were 0.54-2.39%, and the recoveries were 93-105%.

Novel approach over template molecule elimination in molecularly imprinted polymers by using heat activated persulfate

This study proposes a new alternative for template removal from molecularly imprinted polymers by heat activated persulfate. It is known that trace amounts of template molecule remains in the polymer network after extraction by current methodologies leading to bleeding and incomplete removal of template which could compromise final determination of target analytes especially in trace analysis. A previously developed molecularly imprinted polymer specially designed for Coenzyme Q10 (CoQ10) extraction was employed as a model to test this template elimination approach. This polymer is based on methacrylic acid and ethylene glycol dimethylacrylate as monomers and Coenzyme Q0 as template. This coenzyme has the same quinone group as the CoQ10. Selectivity was analyzed comparing the recovery of CoQ10 and ubichromenol, a CoQ10 related substance. Chemical degradation using heat-activated persulfate allows the elimination of the template molecule with a high level of efficiency, being a simple and ecological methodology, yielding a polymer that exhibits comparable selectivity and imprinting effect with respect to traditional extraction methods.

Abstract 1127 FANCD2 promotes HR outcomes during DSB repair by stabilizing template and DSB molecules

Abstract 1127 FANCD2 promotes HR outcomes during DSB repair by stabilizing template and DSB molecules

Selective Extraction and Determination of Hydrocortisone and Dexamethasone in Skincare Cosmetics: Analytical Interpretation Using Statistical Physics Formalism

Molecularly imprinted polymers (MIPs), as magnetic extraction adsorbents, are used for the selective, rapid determination and extraction of dexamethasone and hydrocortisone in skincare products. Therefore, in this paper, magnetic molecularly imprinted polymers (MMIPs) and magnetic non-molecularly imprinted polymers (MNIPs) were utilized as adsorbents to describe the adsorption phenomena of dexamethasone and hydrocortisone. This interpretation, based on a statistical physics theory, applies the multilayer model with saturation to comprehend the adsorption of the drugs. Results obtained via numerical simulation revealed that dexamethasone and hydrocortisone adsorption happens via a non-parallel orientation on the surfaces of MMIPs and MNIPs, and they also showed that the adsorption amount of the MMIPs for the template molecule was notably greater than that of the MNIPs at the same initial concentration. The adsorption energy values retrieved from the data analysis ranged between 7.65 and 15.77 kJ/mol, indicating that the extraction and determination of dexamethasone and hydrocortisone is a physisorption process. Moreover, the distribution of a site’s energy was calculated to confirm the physical nature of the interactions between adsorbate/adsorbent and the heterogeneity of the surfaces of the MMIPs and MNIPs. Finally, the thermodynamic interpretation confirmed the exothermicity and spontaneous nature of the adsorption of these drugs on the tested adsorbents.

Synthesis of Molecularly Imprinted Polymers with Magnetite Cores for Ibuprofen Adsorption

Ibuprofen (IBP) is a pollutant that is widely found in aquatic environments due to pharmaceutical waste and the metabolic results of humans who consume the drug. These compounds can cause damage to aquatic ecosystems, genotoxicity, and aquatic toxicity and are harmful to human health. This study aims to selectively adsorb IBP using magnetic molecularly imprinted polymers (MMIPs) synthesized from ibuprofen (IBP) as a template molecule, methacrylic acid (MAA) as a functional monomer, and divinylbenzene (DVB) as a crosslinker with a mole ratio of 1:4:20 in acetonitrile porogen solvent using a bulk polymerization method. Fe3O4 nanoparticles and MMIPs were characterized using X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR), and Scanning Electron Microscope (SEM). IBP adsorption reached optimum conditions at pH 3 with a contact time of 90 minutes and a mass of 25 mg of adsorbent. The adsorption performance of MMIPs for IBP was evaluated by adsorption isotherms and adsorption kinetics. Adsorption of IBP by MMIPs followed the Langmuir adsorption isotherm model with an adsorption capacity of 227.24 mg/g. Kinetic studies showed that the adsorption process followed a pseudo-second-order adsorption kinetic model. MMIPs can adsorb IBP selectively even in the presence of interfering compounds, are easily separated from the solution, and can be used repeatedly with good adsorption ability. Hence, it is efficient and promising for removing IBP from aqueous media.

A sensor based on Fe/B/N codoped hierarchical porous carbon spheres that amplify the aggregation-induced electrochemiluminescence of calcein for florfenicol trace detection

Electrochemiluminescence (ECL) signal amplification is an important method for improving sensor sensitivity. In this study, an ECL sensor was developed for florfenicol detection based on the aggregation-induced electrochemiluminescence of calcein and Fe/B/N codoped hierarchical porous carbon spheres (B-N-Fe-HPCs). First, B-N-Fe-HPCs were prepared by a simple high-temperature synthesis method, attached to the gold electrode surface, and used as a signal amplification element. Then, a molecularly imprinted polymer (MIP) was prepared using florfenicol as a template molecule and phthalylenediamine as a functional monomer and doped with calcein on the B-N-Fe-HPC-modified electrode. After the elution of florfenicol, the sensor retains an imprinted site that specifically recognizes florfenicol can readsorb florfenicol in the sample. Because calcein aggregates in the MIP to generate an ECL signal, B-N-Fe-HPCs effectively amplifies this ECL signal. Thus, because the ECL signal of the sensor can be quenched, a new method for detecting florfenicol was established. The sensor used for florfenicol showed very high sensitivity and good selective performance, with a linear range of 1–8000 × 10−12 mol/L and a detection limit of 4.65 × 10−13 mol/L. The sensor was applied to detect actual samples, such as chicken, and the results were satisfactory, with the recovery rate of the spike from 91.2 % to 105.3 %.

Selective Extraction of Diazepam and Its Metabolites from Urine Samples by a Molecularly Imprinted Solid-Phase Extraction (MISPE) Method.

In this research, a molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using oxazepam (OZ) as a template molecule and was subsequently applied as a selective sorbent for the extraction of diazepam (DZP) and its metabolites in urine samples using an SPE cartridge. OZ, temazepam (TZ), nordiazepam (NZ) and DZP were analyzed in the final extracts by high-performance liquid chromatography with diode array detection (HPLC-DAD). The SPE extraction steps were optimized, and the evaluation of an imprinting factor was carried out. The selectivity of the method for OZ versus structurally related benzodiazepines (BZDs), such as bromazepam (BRZ), tetrazepam (TTZ) and halazepam (HZ), was investigated. Under the optimum conditions, the proposed methodology provided good linearity in the range of 10-1500 ng/mL, with limit of detection values between 13.5 and 21.1 ng/mL and recovery levels for DZP and its metabolites from 89.0 to 93.9% (RSD ≤ 8%) at a concentration level of 1000 ng/mL. The proposed method exhibited good selectivity, precision and accuracy and was applied to the analysis of urine samples from a real case of DZP intake.