RESUMEN
A functional material was developed with specific recognition properties for aflatoxins for pre-processing enrichment and separation in the detection of aflatoxins in Chinese herbal medicines. In the experiment, ethyl coumarin-3-carboxylate, which has a highly similar structure to the oxonaphthalene o-ketone of aflatoxin, was selected as a pseudo-template, zinc acrylate, neutral red derivative, and methacrylic acid, which have complementary functions, were selected as co-monomers to prepare a pseudo-template multifunctional monomer molecularly imprinted polymer (MIP). The MIP obtained under the optimal preparation conditions has a maximum adsorption capacity of 0.036 mg/mg and an imprinting factor of 3.67. The physical property evaluation of the polymers by Fourier infrared spectrometer, scanning electron microscopy, pore size analyzer, thermogravimetric analyzer, and diffuse reflectance spectroscopy showed that the MIP were successfully prepared and porous spherical-like particles were obtained. The synthesized polymer was used as a solid-phase extraction agent for the separation of aflatoxins from the extract of spina date seed. The linear range of the developed method was 10-1000 ng/mL, the limit of detection was 0.36 ng/mL, the limit of quantification was 1.19 ng/mL, and the recoveries of the extracts at the concentration level of 0.2 µg/mL were in the range 88.0-93.4%, with relative standard deviations (RSDs) of 1.97% (n). The results showed that the preparation of MIPs using ethyl coumarin-3-carboxylate as a template was simple, economical, and convenient. It is expected to become a promising functional material for the enrichment and separation aflatoxins from complex matrices.
Asunto(s)
Aflatoxinas , Polímeros Impresos Molecularmente , Extracción en Fase Sólida , Aflatoxinas/análisis , Polímeros Impresos Molecularmente/química , Extracción en Fase Sólida/métodos , Adsorción , Impresión Molecular , Límite de Detección , Acrilatos/química , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/análisis , Metacrilatos/química , Polímeros/químicaRESUMEN
Development of selective enrichment materials for the accurate analysis of ochratoxin a (OTA) in environmental and food samples is an effective way to protect human health. Here, a molecularly imprinted polymer (MIP) known as plastic antibody was synthesized onto the magnetic inverse opal photonic crystal microsphere (MIPCM) using a low-cost dummy template imprinting strategy targeting OTA. The MIP@MIPCM exhibited ultrahigh selectivity with an imprinting factor of 130, high specificity with cross-reactivity factors of 3.3-10.5, and large adsorption capacity of 60.5 µg/mg. Such MIP@MIPCM was used for selective capture of OTA in real samples which was quantified in combination with high-performance liquid chromatography, giving a wide linear detection range of 5-20,000 ng/mL, a detection limit of 0.675 ng/mL, and good recovery rates of 84-116%. Moreover, the MIP@MIPCM can be produced simply and rapidly and is very stable under different environmental conditions and easy to store and transport, so it is an ideal substitute of biological antibody modified materials for the selective enrichment of OTA in real samples.
Asunto(s)
Impresión Molecular , Polímeros Impresos Molecularmente , Humanos , Impresión Molecular/métodos , Microesferas , Polímeros/química , Cromatografía Líquida de Alta Presión , Adsorción , Fenómenos MagnéticosRESUMEN
Determination of amphetamine-type drugs (ATSs) in urine and wastewater is a simplified approach for the widespread monitoring of ATSs abuse. To improve the sensitivity of the analytical methods, molecularly imprinted polymers (MIPs) based solid-phase extraction (SPE) pretreatment attracted great attention in this field. Generally, smaller particle sizes and more uniform morphology of the MIPs could provide higher detection sensitivity. Our previous works showed reflux precipitation polymerization (RPP) is a method for synthesizing monodispersed MIPs with small particle size. However, synthesis of uniform spherical MIPs towards a group of targets has never been reported. Therefore, in the present work, MIPs towards a group of ATSs were synthesized via RPP with a pseudo template for the first time. After screening potential pseudo-templates, N-methylphenylethylamine (MPEA) was selected as the optimal pseudo-template. MPEA-MIPs were characterized by scanning electron microscope (SEM), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS) spectra. Adsorption isotherms, adsorption kinetics and selectivity were evaluated, and the experimental results indicated that the MPEA-MIPs possessed good selectivity and adsorption property towards ATSs. After optimization of the MIP-SPE procedure, the MIP-SPE cartridges were then coupled with liquid chromatography and tandem mass spectrometry (LC-MS/MS) for determination of ATSs. The evaluation results showed that MIP-SPE-LC-MS/MS displayed good linearity (R2 >0.991) in the linear range (1.0-50.0 µg/L for urine and 0.5-50.0 µg/L for wastewater), and low matrix effect (85-112%). The limit of detection (LOD) was 0.05 -0.29 µg/L, and the accuracy (85-115%) and repeatability (RSD ≤ 15%) were satisfactory at low, medium and high concentrations. To the best of our knowledge, this is the first time that dummy MIPs towards a group of ATSs were synthesized by RPP polymerization, which showed great potential for the detection of ATSs in urine and wastewater.
Asunto(s)
Estimulantes del Sistema Nervioso Central , Impresión Molecular , Anfetamina , Cromatografía Liquida , Polímeros Impresos Molecularmente , Aguas Residuales , Polimerizacion , Espectroscopía Infrarroja por Transformada de Fourier , Polímeros/química , Espectrometría de Masas en Tándem/métodos , Extracción en Fase Sólida/métodos , Impresión Molecular/métodos , Adsorción , Cromatografía Líquida de Alta Presión/métodosRESUMEN
2,4,6-trihalorophenol disinfection by-products (DBPs) have strong toxicity to be needed for monitoring. In this study, two kind of molecularly imprinted polymeric fibers were prepared using 2,4,6-trichlorophenol as template and tricuronic phloroglucinol (MOP) as pseudo-template, respectively. The two fibers were assembled as solid phase microextraction (SPME) fiber to extract 2,4,6-trihalophenol DBPs from water and detect them by gas chromatography coupled to electron capture detector (GC-ECD). The results of F-test and t-test stated that there are significant difference in the analytical results of 2,4,6-trichlorophenol between using the fiber based on 2, 4, 6-trichlorophenol as template and MOP as pseudo-template. It was found that the carry-over of template (2,4,6-trichlorophenol) leaked from the fiber in GC thermal desorption, resulting in the wrong quantitative analytical result for 2,4,6-trichlorophenol in water. Hence, molecularly imprinted polymeric fibers based on MOP as pseudo-template was applied for the determination of 2,4,6-trihalophenol DBPs in water combined with GC-ECD. The selectivity of the fiber for 2,4,6-trihalophenol DBPs was investigated and demonstrated. Under the optimized condition, the method has much lower limit of detection (0.5-1.1 pg mL-1) than most reported methods. The method was applied for the determination of 2,4,6-trihalophenol DBPs in environmental water and the relative recoveries were found to be in the range from 77.1% to 105.6% and the relative standard deviation was 0.5-9.4%. 2,4,6-tribromophenol was found at concentration of 0.054 ng mL-1 in a swimming pool.
Asunto(s)
Impresión Molecular , Microextracción en Fase Sólida , Cromatografía de Gases/métodos , Desinfección , Impresión Molecular/métodos , Polímeros/química , Microextracción en Fase Sólida/métodos , AguaRESUMEN
Zearalenone (ZEA) is a fungal contaminant widely found in grains. In cereal samples, trace zearalenone was extracted and enriched using magnetic-surfaced pseudo molecularly imprinted polymers (SPMIPs) and detected. SPMIPs were prepared with Fe3O4 as the magnetic core, modified halloysites nanotubes as supporting materials, and selective imprinted polymers as shells. Vinyl was modified on the surface of halloysites nanotube. SPMIPs were synthesized with pseudo templates. SPMIPs as the adsorbent of dispersed-solid phase extraction (µ-SPE) were used to purify and enrich ZEA from maize samples. After optimized, the pretreatment method was evaluated. The linearity of the method was ranged within 10-200â¯ngâ¯mL-1. LOD and LOQ were 2.5â¯ngâ¯mL-1 and 8â¯ngâ¯mL-1 respectively. The ZEA spiking recoveries in maize samples ranged within 74.95-88.41% were with good RSDs lower than 4.25%. The developed method was successful applied in maize, oat, and wheat sample treatments and compared.
Asunto(s)
Avena/química , Grano Comestible/química , Impresión Molecular/métodos , Polímeros/química , Triticum/química , Zea mays/química , Zearalenona/química , Adsorción , Cromatografía Líquida de Alta Presión , Magnetismo , Extracción en Fase Sólida/métodosRESUMEN
A core consisting of nanoporous carbon (MNPC) and magnetized with Co3O4 was coated with a molecularly imprinted polymer (MIP) by atom transfer radical precipitation polymerization. Ethyl 3-coumarincarboxylate was used as a pseudo-template to give a MIP that has a fairly specific recognition capability for aflatoxins. Batch rebinding studies were carried out to determine the specific adsorption equilibrium and specific recognition. Extraction is achieved in a single step by mixing and vortexing the sample extract with the Co-MNPC@MIP. The loaded nanosorbent was then magnetically separated and eluted with acetonitrile/water (6/4, v/v). The aflatoxins were then quantified by HPLC. Under optimal conditions, the detection limits for aflatoxins typically are 0.05-0.07 ng mL-1, recoveries from spiked corn are found to be 75.1 to 99.4%, and relative standard deviations range from 1.7 to 5.1 (n = 6). Graphical abstract Poly(methacrylic acid) was imprinted with the pseudo-template ethyl 3-coumarincarboxylate by atom transfer radical precipitation polymerization on the surface of cobalt-derived magnetic nanoporous carbon (Co-MNPC). This nanosorbent was used for the magnetic solid phase extraction of aflatoxins, followed by HPLC analysis.
Asunto(s)
Aflatoxinas/aislamiento & purificación , Carbono/química , Imanes/química , Impresión Molecular , Nanoporos , Polímeros/síntesis química , Extracción en Fase Sólida/métodos , Aflatoxinas/análisis , Aflatoxinas/química , Cobalto/química , Límite de Detección , Óxidos/química , Polimerizacion , Polímeros/químicaRESUMEN
A polymer-based adsorption medium with molecular recognition ability for homologs of pyrethroids was prepared by atom transfer radical polymer iration using a fragment imprinting technique. Phenyl ether-biphenyl eutectic was utilized as a pseudo-template molecule, and the adsorption medium prepared was evaluated by solid-phase extraction and gas chromatography. Selectivity of the medium for pyrethroids was evaluated using it as solid phase extraction packing by Gas Chromatography. The results demonstrated that the absorption amount of bifenthrin, fenpropathrin, permethrin, cypermethrin, fenvalerate, Dursban and pentachloronitrobenzene for molecularly imprinted polymers were 2.32, 2.12, 2.18, 2.20, 2.30, 1.30 and 1.40mgg-1, respectively, while the non-imprinted polymers were 1.20, 1.13, 1.25, 1.05, 1.20, 1.23 and 1.32mgg-1, respectively. The rebinding test based on the molecularly imprinted solid phase extraction column technique showed the recoveries of honey sample spiked with seven insecticides within 88.5-106.2%, with relative standard deviations of 2.38-5.63%. Finally, the method was successfully applied to the analysis of pyrethroids in a honey sample.
Asunto(s)
Impresión Molecular , Polimerizacion , Polímeros/síntesis química , Piretrinas/aislamiento & purificación , Extracción en Fase Sólida , Absorción Fisicoquímica , Miel/análisis , Piretrinas/químicaRESUMEN
A pseudo template molecularly imprinted polymer (MIP) for selective extraction of ß-agonists was prepared using 4-hydroxyphenethyl alcohol as pseudo template molecule, methyl acrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker. Selectivity and adsorption capacity of prepared MIP were studied in detail. MIP selectively adsorbed 14 types of ß-agonists. Advantages of the prepared polymer include non-template leakage in purification of target analytes and cheap cost. MIP was used to purify ß-agonists in urine samples. The developed method was combined with ultra-performance liquid chromatography-tandem mass spectrometry. In optimum conditions, recoveries of the developed method ranged from 84.2% to 109.8% with low coefficients of variation at below 15%. Limits of detection and quantification for 14 target ß-agonists in urine samples reached below 0.05ng/mL and 0.1ng/mL, respectively. The developed method based on MIP enrichment and purification were successfully applied to analysis of target analytes in 50 actual urine samples.
Asunto(s)
Agonistas Adrenérgicos beta/orina , Cromatografía Líquida de Alta Presión , Impresión Molecular , Polímeros/química , Espectrometría de Masas en Tándem , Urinálisis/métodos , Agonistas Adrenérgicos beta/análisis , Animales , Límite de Detección , Urinálisis/instrumentaciónRESUMEN
Through precipitation polymerization, three monodisperse molecularly imprinted polymers (MIPs) containing imprints of 2,4-diamino-6-methyl-1,3,5-triazine (DM), cyromazine (CY) or trimethoprim (TM), were synthesized using methacrylic acid as functional monomer, divinylbenzene as cross-linker, and a mixture of acetonitrile-toluene (90/10, v/v) as porogen. The morphology and selectivity of the MIPs were characterized and compared systematically. The MIPs had the best specific binding in pure acetonitrile, and the data of adsorption experiment were fitted well with Langmuir and Freundlich model. In addition, DM-MIPs showed the excellent binding and multi-recognition capability for CY, melamine (ME), triamterene (TA) and TM, and the binding capacity were 7.18, 7.56, 5.66 and 5.45µmol/g, respectively. Due to the pseudo template and the ability of multi-recognition, DM-MIPs as sorbent material could avoid the effect of template leakage on quantitative analysis. Therefore, DM-MIPs were used as a solid-phase extraction material to enrich ME, CY, TA and TM from different bio-matrix samples for high performance liquid chromatography analysis. Under the optimized conditions, the recoveries of three spiked levels in different bio-matrix samples were ranged from 80.9% to 91.5% with RSD≤4.2 (n=3).