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1.
Water Res ; 168: 115164, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31629229

RESUMO

Carbamazepine (CBZ) is a typical pharmaceutical residue commonly found in aqueous environments, but its removal through activated carbon or advanced oxidation processes is often disrupted by co-existing organic matter. An imprinting system which consisted of the target pollutant CBZ (template molecule) and 10 different kinds of functional monomers was constructed via molecular simulation to screen for appropriate monomers, thereby addressing CBZ removal disruptions. An annealing method simulation was used to search for stable, low-energy conformations of the template-monomer interaction system to calculate the binding energy of these different monomers with CBZ. The order of binding affinity calculated was: 4-vinylbenzoic acid > itaconic acid > methacrylic acid, which was consistent with the experimental observations. The adsorption capacity of the molecular imprinted polymer (MIP) prepared using 4-vinylbenzoic acid reached 28.40 mg/g, and the imprinting factor reached 2.72. The simulation and measurement of the ultraviolet spectrum of the imprinting system showed that a new interaction system was formed between the template and monomers, and that multiple binding conformations between them took place when specific recognition occurred. Energy calculation and hydrogen bond analysis revealed that the van der Waals force, including the π-π conjugate and electrostatic forces including hydrogen bonding, played an important role during selective adsorption, which was confirmed by infrared spectroscopy analysis.


Assuntos
Poluentes Ambientais , Impressão Molecular , Preparações Farmacêuticas , Adsorção , Carbamazepina
2.
Bioelectrochemistry ; 130: 107287, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31400567

RESUMO

This work reports the first electrochemical molecularly imprinted polymer (MIP) sensor for Interleukin-1beta (IL-1ß) detection, based on modified commercial screen-printed carbon electrode (SPCE) was successfully demonstrated. For this purpose, the carbon support was modified with a PEDOT/4-aminothiophenol layer prior to the MIP film to enhance sensitivity and signal stability. The MIP layer was constructed on top of this by electropolymerization of Eriochrome black T (EBT) in the presence of IL-1ß. The several steps of the biosensor assembly was followed by Raman spectroscopy and electroanalytical techniques. Using electrochemical impedance spectroscopy (EIS), a linear response in the range of 60 pM to 600 nM, with a LOD of 1.5 pM with (S/N = 3) was obtained in neutral PBS. Selectivity tests of the MIP biosensor made in spiked synthetic serum samples as well as against other structurally related (Myoglobin, of similar shape and size) or competing compounds (Immunoglobulin G, also present in the human serum) confirmed the good selectivity of the biosensor. Overall, the biosensor described herein has the potential to provide a simple and quick way for on-site screening of IL-1ß, with low sample/reagent consumption and enabling direct serum analysis, which constitutes a valuable alternative to other conventional methods.


Assuntos
Técnicas Biossensoriais/métodos , Interleucina-1beta/sangue , Impressão Molecular/métodos , Compostos Azo/química , Técnicas Biossensoriais/instrumentação , Carbono/química , Espectroscopia Dielétrica/instrumentação , Espectroscopia Dielétrica/métodos , Eletrodos , Desenho de Equipamento , Humanos , Interleucina-1beta/análise , Impressão Molecular/instrumentação , Polimerização , Polímeros/química
3.
Planta Med ; 85(13): 1107-1113, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31382302

RESUMO

Pyrrolizidine alkaloids are secondary plant constituents that became a subject of public concern because of their hepatotoxic, pneumotoxic, genotoxic, and cytotoxic effects. Due to disregardful harvesting and/or contamination with pyrrolizidine alkaloid-containing plants, there is a high risk of ingesting these substances with plant extracts or natural products. The limit for the daily intake was set to 0.007 µg/kg body weight. If contained in an extract, cleanup methods may help to minimize the pyrrolizidine alkaloid concentration. For this purpose, a material for depleting pyrrolizidine alkaloids in herbal preparations was developed based on the approach of molecular imprinting using monocrotaline. Molecular imprinted polymers are substances with specific binding characteristics, depending on the template used for imprinting. By means of group imprinting, only one molecule is used for creating selective cavities for many molecular pyrrolizidine alkaloid variations. Design of Experiment was used for the development using a 25 screening plan resulting in 64 polymers (32 MIPs/32 NIPs). Rebinding trials revealed that the developed material can compete with common cation exchangers and is more suitable for depleting pyrrolizidine alkaloids than C18- material. Matrix trials using an extract from Chelidonium majus show that there is sufficient binding capacity for pyrrolizidine alkaloids (80%), but the material is lacking in selectivity towards pyrrolizidine alkaloids in the presence of other alkaloids with similar functional groups such as berberine, chelidonine, and coptisine. Beyond this interaction, the selectivity could be proven for other structurally different compounds on the example of chelidonic acid.


Assuntos
Impressão Molecular/métodos , Extratos Vegetais/isolamento & purificação , Alcaloides de Pirrolizidina/isolamento & purificação , Adsorção , Benzofenantridinas/isolamento & purificação , Berberina/análogos & derivados , Berberina/isolamento & purificação , Chelidonium/química , Echium/química
4.
Mar Pollut Bull ; 146: 591-597, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426197

RESUMO

A molecularly imprinted polymer (MIP) anchored on the surface of CdTe quantum dots (QDs) was fabricated and used as a fluorescent probe for sulfadiazine (SDZ) detection in seawater. CdTe QDs was used as photoluminescent material, SDZ as the template, 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethyl orthosilicate (TEOS) as the cross-linking agent. Characterizations of MIP-QDs were analyzed by Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM) and Scanning electron microscope (SEM). The conditions were optimized for the detection of MIP-QDs to SDZ. The mechanism of fluorescence quenching was studied by UV-Vis absorption spectroscopy and fluorescence spectroscopy. Under optimal conditions, the fluorescence intensity of MIP-QDs decreased linearly between 4- and 20 µM SDZ with a good correlation coefficient of 0.995. The limit of detection is 0.67 µM and the recovery is between 91.8 and 109.4% with RSD lower than 3.9%. These results indicated that MIP-QDs for SDZ detection in seawater was developed successfully.


Assuntos
Compostos de Cádmio/química , Pontos Quânticos/química , Água do Mar/análise , Sulfadiazina/análise , Telúrio/química , Poluentes Químicos da Água/análise , Antibacterianos/análise , Corantes Fluorescentes/química , Limite de Detecção , Microscopia Eletrônica de Transmissão , Impressão Molecular/métodos , Polímeros/síntese química , Polímeros/química , Propilaminas/química , Silanos/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
5.
Food Chem ; 298: 125066, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31261009

RESUMO

A ultrasensitive chemiluminescence (CL) method for the determination of fluoroquinolones (FQs) in milk was proposed based on the enhancement effect of FQs on the CL reaction between cerium(IV) and methoxylated Cypridina luciferin analogs (MCLA). Prior to the CL determination, molecularly imprinted polymers (MIPs) with superior recognition performances were adopted to the clean-up and extraction of the family of FQs. Then the developed CL system coupling with MIPs (MIP-CL) was applied to the selective determination of FQs in milk. Under the optimized conditions, the method was validated with respect to linearity, precision, accuracy, limits of detection and quantification. The relative standard deviation (RSD) on intra-day assay was below 5.1%, and detection limit was as low as 0.10 nmol/L. The consistency of this method and HPLC method was compared and validated by the paired t-test. The results indicated that the proposed method allowed class-specific determination of FQs in complex matrices.


Assuntos
Fluoroquinolonas/análise , Medições Luminescentes/métodos , Impressão Molecular/métodos , Polímeros/química , Animais , Cério/química , Fluoroquinolonas/isolamento & purificação , Limite de Detecção , Leite/química , Extração em Fase Sólida
6.
J Chromatogr A ; 1602: 168-177, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31303311

RESUMO

In this work, we presented the preparation of magnetic carbon nanotubes (MCNTs) functionalized with molecularly imprinted polymers (MIPs) for effective removal of aristolochic acid I (AAI) in traditional Chinese medicine (TCM). MCNTs@AAI-MIPs was obtained via a facile and environmental friendly sol-gel process. Firstly, MCNTs were synthesized by a solvothermal method. Then, the template molecules were self-assembled with the functional monomer phenyltrimethoxysilane (PTMOS) in the presence of ethanol and water. Finally, AAI-MIPs film was coated on the MCNTs to obtain product MCNTs@AAI-MIPs using tetraethyl-orthosilicate (TEOS) as cross-linker. The morphology and structure of prepared MIPs were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen gas adsorption and vibrating sample magnetometer (VSM). The adsorption properties were demonstrated by kinetic, isothermal and selective adsorption experiments. The results showed that the imprinted nanocomposites exhibited fast separation rate (10 s), high adsorption capacity (18.54 µg∙mg-1), short kinetic equilibrium time (15 min), and good selectivity to template molecule with imprinting factor (IF) of 3.17. A regression equation (y=57294x-4734.1) with good linearity was obtained in the concentration range of 0.1-200 µg∙mg-1 for AAI with a correlation coefficient (R2) of 0.9998. The limit of detection (LOD, S/N=3) was 0.034 µg∙mg-1. Moreover, high recoveries ranged from 80% to 110% (RSD=3.27%-8.16%) were received in spiked TCM samples. The results suggested that the proposed MCNTs@AAI-MIPs could efficiently and specifically capture AAI from an actual complex TCM samples.


Assuntos
Ácidos Aristolóquicos/isolamento & purificação , Magnetismo , Impressão Molecular/métodos , Nanotubos de Carbono/química , Polímeros/química , Adsorção , Cinética , Nanotubos de Carbono/ultraestrutura , Nitrogênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Difração de Raios X
7.
Anal Bioanal Chem ; 411(23): 6081-6090, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273411

RESUMO

A nanooptosensor based on the fluorescence quenching of a composite probe was fabricated for the detection of sarafloxacin. The components of the nanocomposite fluorescent probe were a high affinity material of polydopamine polymer (PDA), a selective material of molecularly imprinted polymer (MIP), and optically sensitive quantum dots (QDs). The developed nanocomposite fluorescent probe exhibited excellent selectivity and sensitivity for sarafloxacin. The molecularly imprinted polymer had an imprinting factor (IF) of 8.18 and produced a probe that quenched fluorescence more effectively than a non-imprinted polymer (NIP) probe. The emission intensity of the MIP probe was linearly quenched by sarafloxacin over a range of 0.10 to 15.0 µg L-1 with a determination coefficient (R2) of 0.9966. The developed nanooptosensor had a limit of detection of 0.05 µg L-1. The optosensor detected sarafloxacin in chicken meat samples with recoveries ranging from 82.8 to 99.1% with an RSD below 3%. The found concentrations in spiked samples were compared well with recoveries obtained by HPLC method of detection. This developed nanooptosensor is simple to operate and cost-effective and the analytical procedure is rapid. Graphical abstract.


Assuntos
Antibacterianos/análise , Ciprofloxacino/análogos & derivados , Contaminação de Alimentos/análise , Indóis/química , Carne/análise , Impressão Molecular/métodos , Polímeros/química , Pontos Quânticos/química , Animais , Galinhas/metabolismo , Ciprofloxacino/análise , Corantes Fluorescentes/química , Limite de Detecção , Aves Domésticas/metabolismo , Pontos Quânticos/ultraestrutura
8.
Food Chem ; 298: 125044, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260971

RESUMO

Fumonisin B1 (FB1) is a carcinogenic mycotoxin produced by Fusarium species contaminating maize. At present, fumonisin determination is performed using costly and demanding chromatography techniques or immunoassays. Recently, a molecularly imprinted polymer nanoparticles (nanoMIPs) - based assay (MINA) has been developed for FB1 detection. Herein, we have applied MINA for the determination of FB1 in naturally contaminated maize samples and results were compared with those obtained with ELISA and a reference HPLC method (AOAC No. 2001.04). The nanoMIPs as a recognition element mimicking antibodies used in ELISA were produced by solid phase synthesis and used in MINA for FB1 determination in 53 maize samples. As a result, 18 maize samples were contaminated with FB1 at levels higher than 0.25 mg/kg. Fumonisin concentrations from samples measured by MINA were well correlated with those using ELISA and HPLC. Therefore, MINA could be used as an alternative technique for FB1 determination in maize.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Fumonisinas/análise , Impressão Molecular , Nanopartículas/química , Polímeros/química , Zea mays/química , Cromatografia Líquida de Alta Pressão , Zea mays/metabolismo
9.
Chem Commun (Camb) ; 55(67): 9927-9930, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31334708

RESUMO

Tyrosine phosphorylation regulates the upstream signaling pathway but accounts for less than 0.1% of total phosphorylation in human cells. Herein, molecularly imprinted mesoporous materials were first synthesized to recognize the phosphorylated tyrosine residue from other phosphorylated residues.


Assuntos
Epitopos , Impressão Molecular , Nanopartículas/química , Compostos Organofosforados/química , Dióxido de Silício/química , Tirosina/metabolismo , Adsorção , Cinética , Fosfopeptídeos/química , Fosforilação , Porosidade , Titânio/química
10.
Anal Chim Acta ; 1077: 255-265, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307717

RESUMO

Herein, we propose a highly sensitive and selective three-dimensional electrochemical paper-based analytical device (3D-ePAD) to determine serotonin (Ser). It uses a graphite-paste electrode modified with nanoparticles coated with molecularly imprinted polymer (MIP). Fe3O4@Au nanoparticles were encapsulated with silica to create novel nano-sized MIP. Morphology and structural characterization reveal that silica imprinted sites (Fe3O4@Au@SiO2) synthesized via sol-gel methods provide excellent features for Ser detection, including high porosity, and greatly improve analyte diffusion and adsorption to provide a faster response by the MIP sensor. The template molecule was effectively removed by solvent extraction to provide a greater number of specific cavities that enhance analyte capacity and sensitivity. The 3D-ePAD was fabricated by alkyl ketene dimer (AKD)-inkjet printing of a circular hydrophobic detection zone on filter paper for application of aqueous samples, coupled with screen-printed electrodes on the paper, which was folded underneath the hydrophobic zone. The sensor was constructed by drop coating of Fe3O4@Au@SiO2-MIP nanocomposites on the graphite electrode (GPE) surface. The MIP sensor (Fe3O4@Au@SiO2-MIP/GPE) was used in the detection of Ser by linear-sweep voltammetry (LSV) in 0.1 M phosphate buffer at pH 8.0. The device exhibits high sensitivity toward Ser, which we attribute to synergistic effects between catalytic properties, electrical conductivity of Fe3O4@Au@SiO2, and significantly increased numbers of imprinted sites. Ser oxidation was observed at +0.39 V. Anodic peak currents for Ser show linearity from 0.01 to 1000 µM (y = 0.0075 ± 0.0049 x + 0.4071 ± 0.0052, r2 = 0.993), with a detection limit of 0.002 µM (3S/N). The device provides good repeatability (%relative standard deviations; RSD) = 4.23%, calculated from the current responses of ten different MIP sensors). The device also exhibits high selectivity and reproducibility (%RSD = 8.35%, obtained from five calibration plots). The analytical performance of the device is suitable for the determination of Ser in pharmaceutical capsules and urine samples.


Assuntos
Ouro/química , Nanopartículas de Magnetita/química , Povidona/química , Serotonina/análise , Dióxido de Silício/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/química , Limite de Detecção , Impressão Molecular , Papel
11.
Talanta ; 202: 111-122, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171159

RESUMO

A new dual-modality immunosensor based on molecularly imprinted polymer (MIP) and a nanostructured biosensing layer has fabricated for the simultaneous detection of two important markers including prostate-specific antigen (PSA) and myoglobin (Myo) in human serum and urine samples. In the first step, 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) (DSP) was self-assembled on a gold screen printed electrode (SPE). Then, the target proteins were attached covalently to the DSP-SPE. The imprinted cocktail polymer ((MIP(PSA, Myo)-SPE)) was synthesized at the SPE surface using acrylamide as monomer, N,N'-methylenebisacrylamide as a crosslinker, and PSA and Myo as the templates, respectively. The MIP-SPE was specific for the impedimetric sensing of PSA and Myo. After that, a nanocomposite (NCP) was synthesized based on the decorated magnetite nanoparticles with multi-walled carbon nanotube, graphene oxide and specific antibody for PSA (Ab). Then, NCP incubated with (MIP(PSA, Myo)-SPE. The modified electrodes and synthesized nanoparticles were characterized using electrochemical impedance spectroscopy, dynamic light scattering, surface plasmon resonance and scanning electron microscopy. The limits of detections were found to be 5.4 pg mL-1 and 0.83 ng mL-1 with the linear dynamic ranges of 0.01-100 and 1-20000 ng mL-1 for PSA and Myo, respectively. The ability of proposed biosensor to detect PSA and Myo simultaneously with high sensitivity and specificity offers a powerful opportunity for the new generation of biosensors. This dual-analyte specific receptors-based device is highly desired for the integration with lab-on-chip kits to measure a wide panel of biomarkers present at ultralow levels during early stages of diseases progress.


Assuntos
Biomarcadores Tumorais/análise , Técnicas Biossensoriais , Técnicas Eletroquímicas , Mioglobina/análise , Polímeros/química , Antígeno Prostático Específico/análise , Neoplasias da Próstata/diagnóstico , Anticorpos/imunologia , Reações Antígeno-Anticorpo , Biomarcadores Tumorais/imunologia , Eletrodos , Humanos , Masculino , Impressão Molecular , Mioglobina/imunologia , Nanopartículas/química , Antígeno Prostático Específico/imunologia , Neoplasias da Próstata/imunologia
12.
Talanta ; 202: 21-26, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171172

RESUMO

A magnetic surface molecularly imprinted-resonance light scattering sensor was developed for rapid and highly sensitive detection of Japanese encephalitis virus (JEV). To prepare the surface imprinted polymer, Fe3O4 microspheres were selected as imprinting substrates which coated by silicon. Aminopropyl-triethoxysilane (APTES) as functional monomers for fixing template molecules JEV through a polymerization process of tetraethyl-orthosilicate (TEOS). The target virus JEV could be captured by the imprinted particles fastly and selectively, resulting in an increase of the RLS intensity. The results of RLS analysis proved that the obtained imprinted nanoparticles exhibited excellent specific recognition ability and high selectivity for the template virus (JEV). Furthermore, the response time of the sensor is within 20 min, which is much shorter than the previous works. The sensor with convenient separation and the limit of detection was 1.3 pM. These experimental results show that the proposed strategy is expected to achieve rapid and sensitive detection of JEV in practical applications.


Assuntos
Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Luz , Impressão Molecular , Polímeros/química , Campos Magnéticos , Tamanho da Partícula , Espalhamento de Radiação , Propriedades de Superfície
13.
Talanta ; 202: 392-401, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171200

RESUMO

A novel restricted access molecularly imprinted polymers (RAMIPs) fiber was developed for solid-phase microextraction (SPME) of hesperetin and its metabolites in livers of live rats in vivo. Hesperetin as the template, N-isopropylacrylamide as the functional monomer, ethylene glycol dimethyl acrylate as the crosslinker, 2,2-azobisisobutyonnitrile as initiator and bovine serum albumin as the restricted access material were applied in the preparation process. Scanning electron microscopy and Fourier transform infrared spectroscopy were applied to characterize the polymers. The adsorption experiments indicated that RAMIPs-SPME fibers performed high selective recognition property to hesperetin. The selectivity experiment indicated that the adsorption capacity and selectivity of RAMIPs-SPME fibers to hesperetin was higher than that of quercetin, luteolin and baicalein. Macromolecules elimination test showed RAMIPs-SPME fibers could eliminate 94.80%-98.96% of macromolecules, which indicated that RAMIPs-SPME fibers can be used to extract analytes directly from complex biological samples. Furthermore, RAMIPs-SPME sampling combined to ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was applied to capture and identify hesperetin and its metabolites in rat livers in vivo. Finally, hesperetin-7-O-glucuronide, hesperetin-3'-O-glucuronide, eriodictyol and homoeriodictyol were identified as the metabolites of hesperetin. In comparison with the MIPs fibers, commercial PDMS and DVB fibers, RAMIPs-SPME fibers possessed better exclusion effect to macromolecules and higher selectivity to hesperetin and its metabolites. The results demonstrated that the prepared RAMIPs-SPME fiber were proven to be effective tool for the selective adsorption and enrichment of hesperetin and its metabolites from the complex biological fluids.


Assuntos
Hesperidina/análise , Impressão Molecular , Polímeros/química , Microextração em Fase Sólida , Hesperidina/metabolismo
14.
Talanta ; 202: 460-468, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171208

RESUMO

A new on-line solid phase preconcentration method using an ion-imprinted polymer with restrict access material based on copper-imprinted poly(allylthiourea) modified with 2-hydroxyethyl methacrylate and bovine serum (IIP-HEMA-BSA) to preconcentrate Cu2+ ions and exclude protein from milk samples via FIA-FAAS was developed. The samples were on-line preconcentrated at pH 4.5 through a mini-column packed with 50.0 mg of IIP-HEMA-BSA at a flow rate of 7.6 mL min-1 followed by a counter-current elution with 1.00 mol L-1 HCl towards the FAAS detector. The interference of ions commonly found in milk samples and the presence of BSA were investigated in the Cu2+ ions preconcentration. The method provided an analytical curve ranging from 3.6 to 100.0 µg L-1, preconcentration factor of 24-fold, limit of detection of 1.1 µg L-1 and sample throughput of 20 h-1. The accuracy of the method was attested by Cu2+ ions addition/recovery tests as well as by using GFAAS of samples microwave-assisted digested. The proposed method was successfully applied to the copper determination in milk samples, requiring only pH adjustment followed by preconcentration step as sample pretreatment. Copper content in bovine milk sample was 0.635 ±â€¯0.042 mg kg-1, while to soybean milk samples were between 0.048 ±â€¯0.008 and 0.094 ±â€¯0.005 mg kg-1. To the best of our knowledge, the potential of IIP-HEMA-BSA for Cu2+ ions extraction from biological samples and simultaneous removal of macromolecules employing minimal sample pretreatment was demonstrated for the first time. The proposed extraction method stands out by being simple, fast and a low-cost analytical strategy when compared to the conventional microwave-assisted acid digestion.


Assuntos
Cobre/análise , Grafite/química , Leite/química , Impressão Molecular , Polímeros/química , Tioureia/análogos & derivados , Animais , Espectrofotometria Atômica , Tioureia/química
15.
J Chromatogr A ; 1602: 124-134, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31230879

RESUMO

A highly selective and effective method was successfully developed using magnetic molecular imprinted polymers (MMIPs) as solid-phase extraction (SPE) coupled with high performance liquid chromatography-ultraviolet detector (HPLC-UV) to rapidly determine cephalexin (CFX) in complex animal-derived food. MMIPs were creatively synthesized via suspension polymerization using Fe3O4 magnetic nanoparticles as supporter, CFX as template, acrylamide (AM) as functional monomer, and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The MMIPs were characterized using X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The binding process fitted well with pseudo-second-order model with good selectivity. Scatchard plot analysis suggested that MMIPs have two types of binding sites with the Qmax of 24.18 mg g-1 and 40.25 mg g-1, respectively. And Langmuir model proved that the recognition sites were uniformly distributed in a monolayer on the surface of MMIPs. The methodological assessment showed good applicability of MMIPs with excellent recovery (85.5%-94.0%), precision (1.2%-2.4%), and stability (intra-day 1.3%-3.6%; inter-day 2.6%-4.3%) in determining CFX content. In addition, the linearity of the calibration curve was good in the range of 0.02-5.00 mg L-1, with a sensitive detection limit of 5.00 µg kg-1. The results above suggest that the obtained MMIPs exert good performance for separation of CFX in animal-derived food, and the proposed method is suitable for the reliable determination of CFX in complex samples.


Assuntos
Cefalexina/isolamento & purificação , Magnetismo , Leite/química , Impressão Molecular/métodos , Polímeros/química , Carne Vermelha/análise , Adsorção , Animais , Antibacterianos/isolamento & purificação , Cinética , Limite de Detecção , Metacrilatos/química , Nanopartículas/química , Padrões de Referência , Espectroscopia de Infravermelho com Transformada de Fourier , Suínos , Temperatura Ambiente , Difração de Raios X
16.
J Chromatogr A ; 1602: 48-55, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31147154

RESUMO

One of the major drawbacks of conventional molecularly imprinted polymers (MIPs) is the requirements of volatility porogenic solvent during polymerization. To overcome the default, MIP based on deep eutectic solvent (DES, a new type of green designer solvents) has been synthesized successfully. To improve the affinity of the MIP based on DES, in this work, a strategy of metallic pivot was suggested in the first time to prepare a highly selective MIP monolithic column. A cetirizine-imprinted polymer was prepared in a DES-based porogen system composed of choline chloride/ ethylene glycol (ChCl-EG) in the presence of Co(Ac)2 as metallic pivot. The resulting DES- Co2+-MIP monolith had 23.5 times higher imprinting factor than the Co2+-free MIP monolith. The characterization of polymers indicated that DES was one of the primary factor influencing the MIP morphology and pore structure. Compared with previous metal-mediated and ionic liquid-based imprinted polymers, the introduction of DES as a porogen in polymerization led to higher imprinting factor (approximately 2.9 - 17.1 times). In addition, the resulting DES-Co2+-MIP can be used as an adsorbent for extraction of cetirizine from ethanol solution with the recoveries of 97.8%. As a conclusion, the metallic pivot is a rather valuable strategy for the synthesis of DES-based MIP monolith with high selectivity.


Assuntos
Técnicas de Química Analítica/métodos , Metais/química , Impressão Molecular , Polímeros/síntese química , Solventes/química , Cetirizina/química , Cetirizina/isolamento & purificação , Etanol/química , Etilenoglicol , Polimerização , Polímeros/química
17.
J Chromatogr A ; 1602: 11-18, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31160093

RESUMO

Surface molecularly imprinted polymers (MIL-101@MIPs) were prepared using MIL-101 as supporting core, imprinted polymers as selective shell synthesized with coumarin-3-carboxylic acid as dummy template of Zearalenone (ZEN), methacrylic acid as functional monomer, and ethylene glycol dimethacrylate hydroxyethyl methacrylate as cross-linker. The polymers were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and particle-size distribution analyses. MIL-101@MIPs were used as the sorbent to compose the self-made cartridge. The cartridge was used to purify and enrich ZEN from real samples. Under optimized SPE conditions, a self-made cartridge can be reused for at least seven cycles. Elution was monitored with a high-performance liquid chromatography-fluorescence detection system. The linearity of the method ranged within 6.25-250 ng kg-1. The limits of detection ranged within 2.09 - 4.16 ng kg-1, and the limits of quantification ranged within 6.25 -12.50 ng kg-1, respectively. The matrix effects of four real samples were discussed. The spiking recoveries of ZEN ranged within 81.70%-90.10% with relative standard deviations lower than 5.56%. The performance of the self-made cartridge and immunoaffinity column was compared by chromatography.


Assuntos
Grão Comestível/química , Polímeros/síntese química , Extração em Fase Sólida/métodos , Zearalenona/isolamento & purificação , Adsorção , Cromatografia Líquida de Alta Pressão , Cumarínicos/química , Limite de Detecção , Estruturas Metalorgânicas/química , Metacrilatos/química , Impressão Molecular , Oryza/química , Polímeros/química , Triticum/química , Zea mays/química , Zearalenona/análise
18.
J Chromatogr A ; 1602: 30-40, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31164227

RESUMO

Herein we describe a methodology to synthesis polyurethane foam molecularly imprinted polymer (PUF-MIP) by using functional monomer for selective extraction of alprazolam. For this purpose, the various percentages of functional monomer are used to synthesis PUF-MIP of alprazolam. To evaluate the selectivity of synthesized PUF-MIP HPLC analysis is applied by introducing caffeine and methadone as an interference. To optimize the proposed technique, effective parameters in the SPE procedure including pH, flow, and salt present is investigated by experimental design. Finally, this method is evaluated in urine sample to monitor alprazolam dosage. In the optimized condition, the synthesized polymer indicates high selectivity value about 71% for alprazolam and 96.8% recovery for MIPUF compared with non-imprinted polyurethane foam (NIPUF). The linear dynamic range (LDR) of 0.03-60 mg L-1, the limit of detection of 8-10 µg L-1, the relative standard deviation (RSD, n = 3) of 2.88-3.65 % and quantification of 25-30 µg L-1 is obtained for HPLC analysis based on PUF-MIP extraction.


Assuntos
Alprazolam/isolamento & purificação , Monitoramento de Medicamentos/métodos , Poliuretanos/química , Alprazolam/química , Alprazolam/urina , Cafeína/química , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Metadona/química , Impressão Molecular , Polímeros/química , Sais/química , Extração em Fase Sólida
19.
Anal Chim Acta ; 1076: 64-72, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31203965

RESUMO

A new and facile method for selective measurement of profenofos (PFF) using a simple flow-injection system with a molecularly-imprinted-polymer-coated carbon nanotube (3D-CNTs@MIP) amperometric sensor is proposed. The 3D-CNTs@MIP was synthesized by successively coating the surface of carboxylated CNTs with SiO2 and vinyl end groups, then terminating with molecularly imprinted polymer (MIP) shells. MIP was grafted to the CNT cores using methacrylic acid (MAA) monomer, ethylene glycol dimethacrylate (EGDMA) as cross linker, and 2,2'-azobisisobutyronitrile (AIBN) as initiator. We constructed the PFF sensor by coating the surface of a glassy carbon electrode (GCE) with 3D-CNTs@MIP and removed the imprinting template by solvent extraction. Morphological and structural characterization reveal that blending of the MIP on the CNT surface significantly increases the selective surface area, leading to greater numbers of imprinting sites for improved sensitivity and electron transfer. The 3D-CNTs@MIP sensor exhibits a fast response with good recognition when applied to PFF detection by cyclic voltammetry and amperometry. The PFF oxidation current signal appears at +0.7 V vs Ag/AgCl using 0.1 M phosphate buffer (pH 7.0) as the carrier solution. The designed 3D-imprinted sensor provides a linear response over the range 0.01-200 µM (r2 = 0.995) with a low detection limit of 0.002 µM (3σ). The sensor was successfully applied to detection of PFF in vegetable samples.


Assuntos
Contaminação de Alimentos/análise , Inseticidas/análise , Nanotubos de Carbono/química , Organotiofosfatos/análise , Resíduos de Praguicidas/análise , Polímeros/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Limite de Detecção , Impressão Molecular , Nanocompostos/química , Dióxido de Silício/química , Verduras/química
20.
J Chromatogr A ; 1603: 23-32, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31230878

RESUMO

The analyses of drugs and metabolites in complex matrices have been widely studied in recent years. However, due to high levels endogenous compounds and matrix complexity, these analyses require a sample pre-treatment step. To this aim, two lab-made extractive phases were integrated to probe electrospray ionization mass spectrometry (PESI-MS) technique for direct analysis of illicit drugs in biological fluids and phorbol esters in Jatropha curcas extract. The polypyrrole (PPy) phase was electropolymerized onto a platinum wire surface by cyclic voltammetry. The molecularly imprinted polymer (MIP) was synthesized and adhered onto a stainless-steel needle with epoxy resin. The PPy-PESI-MS method showed to be linear in a concentration range from 1 to 500 µg L-1, with accuracy values between -2.1 and 14%, and precision values between 0.8 and 10.8%. The MIP-PESI-MS method showed to be linear in a concentration range from 0.9 to 30 mg L-1, with accuracy values between -1.6 and -15.3%, and precision values between 4.1 and 13.5%.


Assuntos
Impressão Molecular/métodos , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/isolamento & purificação , Polímeros/química , Pirróis/química , Microextração em Fase Sólida/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Cocaína/análise , Cocaína/isolamento & purificação , Voluntários Saudáveis , Humanos , Jatropha/química , Dietilamida do Ácido Lisérgico/análise , Dietilamida do Ácido Lisérgico/isolamento & purificação , Metanfetamina/análise , Metanfetamina/isolamento & purificação , N-Metil-3,4-Metilenodioxianfetamina/análise , N-Metil-3,4-Metilenodioxianfetamina/isolamento & purificação , Ésteres de Forbol/análise , Ésteres de Forbol/isolamento & purificação , Extratos Vegetais/análise , Extratos Vegetais/isolamento & purificação , Saliva/metabolismo , Aço Inoxidável/química , Urinálise
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