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1.
Hu Y  Li J  Li G 《Journal of separation science》2011,34(10):1190-1197
The preparation, characteristics and application of a sorptive stir bar coated with molecularly imprinted polymer (MIP) using triadimefon as the template molecule are described here. Raw glass capillary was coated with MIP through chemical bonding. The synthesis method was effective and reproducible with the batch-to-batch RSD within 7.8%. Scanning electron micrographs of the stir bar revealed a highly porous coating with average thickness of 15 μm. The synthesized stir bar was proved to be highly stable in most of the solvent for use. Extraction performance showed the fabricated stir bar has excellent molecular recognition abilities for triadimefon and the structure-related compounds, such as triadimenol, diniconazole, flutriafol, hexaconazole, tebuconazole, paclobutrazol and uniconazole, and thus can be applied for simultaneous determination of these triazole fungicides from complex samples by coupling with high-performance liquid chromatography. The variables that influence extraction were optimized with 10.0 μg/L standard solutions of triazole fungicides, and the analytical method was established for the determination of triazole fungicides in soil. The detection limits were in the range of 0.14-0.34 μg/L, and the recoveries were from 86.7 to 114.6% for spiked soil sample.  相似文献   

2.
Yuling Hu 《Talanta》2010,82(2):464-4294
A novel stir bar coated with molecularly imprinted polymer (MIP) as selective extraction phase for sorptive extraction of triazine herbicides was developed. The stir bar was prepared by chemically bonding the MIP to the glass bar to improve its stability. A homogeneous and porous structure was observed on the stir bar surface. Extraction performance shows that the MIP-coated stir bar has stronger affinity to the template molecule terbuthylazine as compared with that of the reference stir bar without addition of template. Owning to the shape and structural compatibility, the obtained stir bar also demonstrated specific selectivity to the structural related-compounds of nine triazines, and thus can be applied to simultaneous determination of these compounds from complex samples coupled with high performance liquid chromatography. Four complex samples with different matrix, including rice, apple, lettuce and soil were used to evaluate this proposed method. The limits of detection obtained are in the range of 0.04-0.12 μg L−1, and the recoveries for the spiked rice, apple, lettuce and soil samples were 80.8-107.7%, 80.6-107.8%, 72.0-109.8% and 89.0-114.8% with RSD from 1.2 to 7.9%, respectively. Moreover, this MIP-coated stir bar was firm, durable and can be prepared simply and reproducibly. The developed coating method would be useful to prepare a range of selective stir bars in order to extend the applicability of stir bar sorptive extraction (SBSE) in complex sample analysis.  相似文献   

3.
Xu Z  Song C  Hu Y  Li G 《Talanta》2011,85(1):97-103
A novel sulfamethazine molecularly imprinted polymer (MIP)-coated stir bar for sorptive extraction of eight sulfa drugs from biological samples was prepared. The MIP-coating was about 20 μm thickness with the relative standard deviation (RSD) of 6.7% (n = 10). It was characterized by scanning electron microscope, infrared spectrum, thermogravimetric analysis, and solvent-resistant investigation, respectively. The non-imprinted polymer (NIP)-coating was used for comparison. The adsorptive capacity and selectivity of MIP-coating were evaluated in detail. The MIP-coating showed higher adsorption capability and selectivity than the NIP-coating. The saturated adsorption amount of the MIP-coating was 4.6 times over that of the NIP-coating in toluene. Sulfamethazine could be detected after the MIP-coated stir bar sorptive extraction even at a low concentration of 0.2 μg/L. The MIP-coating also exhibited selective adsorption ability to analogues of the template. A method for the determination of eight sulfa drugs in biological samples by MIP coated stir bar sorptive extraction coupled with high performance liquid chromatography (HPLC) was developed. The extraction conditions, including extraction solvent, extraction time, desorption solvent, desorption time and stirring speed, were optimized. The linear ranges were 1.0-100 μg/L and 2.0-100 μg/L for eight sulfonamides, respectively. The detection limits were within the range of 0.20-0.72 μg/L. The method was successfully applied to simultaneous multi-residue analysis of eight sulfonamides in spiked pork, liver and chicken samples with the satisfactory recoveries.  相似文献   

4.
以双酚A为模板,4-乙烯基吡啶为单体,利用整体材料"原位"聚合技术制备分子印迹聚合物为基质的萃取饼,并与利用一次性注射器空管加工而成的萃取器相结合,建立了分子印迹搅拌饼固相萃取(MIP-SCSE)技术。考察了制备条件对MIP-SCSE选择吸附性能的影响。在此基础上,与高效液相色谱-二极管阵列检测器联用,探讨MIP-SCSE对环境水样中双酚A及其它酚类物质的选择萃取性能,考察萃取过程中基底离子强度、pH值以及吸附与解吸时间等萃取条件对萃取性能的影响。结果表明;在最佳萃取条件下,MIP-SCSE对模板分子及其它酚类物质具有一定选择性能和较高的富集能力,对双酚A的线性范围为1.0~200μg/L;检出限LOD(S/N=3)为0.67μg/L;定量限LOQ(S/N=10)为2.24μg/L。在实际水样分析中,模板分子加标回收率为86.2%~112.2%。在MIP-SCSE使用过程中,萃取饼不与容器壁接触,因此具有优良的使用寿命,至少可连续使用600 h。  相似文献   

5.
In this paper, a novel monolithic stir bar based on molecularly imprinted polymer (MIP) was firstly developed by filling modified neodymium magnet (Nd2Fe14B) powders into a glass tube (60 × 4 mm), followed by the imprinted grafting with bisphenol A (BPA) as the template molecule by thermal polymerization. It has been successfully used for the stir bar sorptive extraction (SBSE) and its extraction performance illustrated that the MIP‐encapsulated stir bar had stronger affinity to the template molecule, compared with the stir bar based on the non‐imprinted molecularly polymer (NIP). Under the optimal extraction conditions, a simple method based on the coupling of MIP‐SBSE with high performance liquid chromatography (HPLC) was used for the selective determination of the model mixtures of BPA, 4‐phenylphenol (PP) and phenol (P) in bottled water. The recoveries of BPA, PP and P were in the range of 88.5‐96.1%, 78.2‐89.7%, 81.3‐89.5% at three spiked levels, respectively, demonstrating that higher extraction and the specific absorption occurred between the template molecule and the prepared MIP stir bar.  相似文献   

6.
In this paper we describe the synthesis, characterisation and use of two distinct molecularly imprinted polymers (MIPs) prepared using esters of p-hydroxybenzoic acid (parabens) as templates: one MIP was synthesised by precipitation polymerisation using a semi-covalent molecularly imprinting strategy with methyl paraben as the template/target (MIP 1); the second MIP was prepared in monolithic form through a conventional non-covalent molecular imprinting strategy, with butyl paraben as the template (MIP 2). MIP 1 recognized methyl paraben, showed cross-selectivity for other parabens analytes used in the study and higher affinity towards these compounds than did a non-imprinted control polymer. Similarly, MIP 2 demonstrated higher affinity towards paraben analytes than a non-imprinted control polymer.For the analysis of environmental water samples, a solid-phase extraction (SPE) protocol was developed using MIP 2 as sorbent, and results were compared to a SPE using a commercial sorbent (Oasis HLB). With MIP 2 as sorbent and butyl paraben as target, when percolating 500 mL of river water spiked at 1 μg L−1 through the SPE cartridge, and using 1 mL of isopropanol as cleaning solvent, a higher recovery of butyl 4-hydroxybenzoate (butyl paraben) and a cleaner chromatogram where achievable when using the MIP compared to the commercial sorbent.  相似文献   

7.
农舒予  林福华  黄晓佳  袁东星 《色谱》2012,30(11):1133-1142
以己烯雌酚为替代模板,利用整体材料的“原位”合成技术制备了分子印迹聚合物,并将其作为固相萃取搅拌棒的涂层(MIP-SBSE)制备了新的搅拌棒。详细考察了分子印迹聚合物制备条件中模板分子及功能单体用量对MIP-SBSE选择性萃取性能的影响,同时利用元素分析、扫描电镜和红外光谱对聚合物进行表征。以双烯雌酚(DS)和己烷雌酚(HS)为目标化合物,将MIP-SBSE与高效液相色谱-二极管阵列检测器联用,建立起复杂样品中DS和HS的分离分析方法。考察了吸附和解吸时间、解吸溶剂、离子强度和样品pH值等萃取条件对MIP-SBSE选择性萃取性能的影响。结果表明,在最佳萃取条件下,MIP-SBSE对DS和HS具有较高的选择性萃取性能,线性范围分别为1.0~400.0 μg/L和5.0~400.0 μg/L,利用氮吹再定容的方法,对DS和HS的检出限(S/N=3)分别可低至0.04和0.14 μg/L。在对实际污水、蜂蜜和牛尿样品的分析中取得了良好的加标回收率,其值为61.3%~120%。所建方法具有简便、高选择性和灵敏等特点,可用于复杂样品中双烯雌酚和己烷雌酚的分析监测。  相似文献   

8.
林福华  黄晓佳  袁东星  刘宝敏 《色谱》2010,28(5):507-512
以双酚A(BPA)为单体,利用整体材料“原位”聚合技术制备以分子印迹聚合物为涂层的吸附萃取搅拌棒(MIP-SBSE),然后与高效液相色谱(HPLC)-二极管阵列检测器联用,探讨其对环境水样BPA的选择萃取性能。优化萃取过程中吸附和解吸时间、解吸液种类以及基底pH值和离子强度对目标化合物的选择吸附性能。在最佳条件下,MIP-SBSE可对模板分子进行有效的选择吸附,线性范围为1.0~200 μg/L,检出限(S/N=3)和定量限(S/N=10)分别为0.28μg/L和0.94 μg/L。在实际水样分析中,具有良好的加标回收率,其值为96.0%~108.7%。研究结果表明,所建立的方法具有简便、灵敏和环境友好等特点。  相似文献   

9.
In this study, molecularly imprinted polymer (MIP) was prepared and used in the preparation of carbon paste electrode (CPE) for the quantification of bisoprolol fumarate (BF) in pure, pharmaceutical formulation and biological fluids. The selective MIP for BF was synthesized from methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker in dimethyl sulfoxide solution, BF as the template molecule and 2, 2-azobisisobutyronitrile (AIBN) as the initiator. The non-imprinted polymer (NIP) was synthesized by the same procedure, but in the absence of the template molecule then incorporated in the paste of the carbon paste electrodes (CPEs). The prepared MIP for BF and its corresponding NIP were well characterized using scanning electron microscopy (SEM), Fourier transform infrared spectrometer, and thermal gravimetric analysis (TGA). The MIP and NIP based CPEs were further used for the determination of BF and the obtained results indicated that the sensor modified by the MIP have much higher recognition power for the BF molecules than the NIP based sensor where the MIP based CPE exhibited a Nernstian response 29.50±0.55 mV decade−1 within a concentration range of 1.0×10−7–1.0×10−2 mol L−1and pH independence in the range 3.50–7.15. The proposed sensor has high selectivity over several possible interfering compounds. The obtained results by the proposed sensor were satisfactory with excellent percentage recovery and relative standard deviation and were comparable with those obtained from HPLC reported method.  相似文献   

10.
A computational approach to screening monomer for preparing molecularly imprinted polymer (MIP) was proposed, using the binding energy, ΔE, of a template molecule and a monomer as a measure of their interaction. For a specified template molecule, a monomer of higher ΔE is suitable for preparing the MIP. To examine the validity of this approach, theophylline (THO) was chosen as the template molecule and methacrylic acid (MAA), acrylamide (AA) and 2-(trifluoromethyl)acrylic acid (TFMAA) were as the functional monomers, respectively. Density functional theory (DFT) at B3LYP/6-31+G**//B3LYP/3-21G level was used to calculate ΔE. It was shown that TFMAA gave the largest ΔE while AA gave the smallest. The details of the interaction between the THO with these monomers were also given by this computing approach. The adsorption of THO on the MIP synthesized using different monomers was studied. The MIP synthesized using TFMAA as monomer showed the highest selectivity to THO while the MIP from AA gave the lowest, as predicted from the ΔE calculation. 1H NMR spectroscopy showed that, compared to MAA and AA, a stronger H-bond interaction is formed between TFMAA and THO. FT-IR analysis of the MIPs prepared using these three monomers confirmed the existence of CO and OH groups, which forms H-bond with THO. The results described above have given an insight into the interaction between THO and the monomers, and shown the use of ΔE to facilitate the selection of monomers for the synthesis of MIP.  相似文献   

11.
A novel poly(methyl methacrylate–ethyleneglycol dimethacrylate–acrylic acid) film has been introduced for coating on stir bars to sorptive extraction (SBSE). The effects of different contents of porogen, monomer, cross-linker, modifier and initiator during the solvent or bulk polymerization step on the mechanical property and solvent resistant of prepared sorptive stir bars were investigated. The evaluation of results were caused to obtain the four prepared sorptive stir bars with good mechanical stability and excellent resistance to organic solvents. The extraction efficiency of these prepared sorptive stir bars were investigated by liquid desorption-liquid chromatography-ultraviolet detection (LD-LC-UV) using N-Nitrosodiphenylamine as target analyte. SBSE assays showed the sorptive stir bar that prepared using solution polymerization method had the better recovery for N-Nitrosodiphenylamine in water samples. This sorptive stir bar showed good linearity and acceptable recoveries, as well as advantages such as sensitivity, simplicity, low cost and high feasibility. Based on atomic force microscopy (AFM) results, the average pore size of optimum prepared stir bar using solvent polymerization method was obtained ~9 nm. The thermal gravity (TG) and differential scanning calorimetric (DSC) results showed this polyacrylate film has high thermal stability.  相似文献   

12.
A new molecularly imprinted polymer (MIP) was prepared using methamidophos (MAP) as the template molecule based on non‐covalent interaction. The complexes formed between template and monomers before polymerization were characterized by 1H NMR titration test, FT‐IR and UV spectrometry study. These studies indicated that a 1:2 molecular complex formed dominantly between MAP and functional monomers. A model mainly involving cooperative hydrogen interaction was proposed by exact placement of functional groups. Association constant was estimated to be 2.894 × 106 L2/mol2. When the initial concentration of MAP was 1.0 mmol L?1, the affinity capacity of MIP was 4.23 times that of NIP. The binding performance of MIP was modeled with the Freundlich isotherm (FI) and the total number of binding sites was calculated to be 33.97 μmol/g. The MIP showed great homogeneity with a heterogeneity index of m = 0.7356. The specificity of MIP was investigated by single‐analyte binding and molecularly imprinted solid‐phase extraction (MISPE) assays using MAP and other structurally related organophorous pesticides (OPPs). The results indicated that the MIP had a marked preference for MAP.  相似文献   

13.
Molecularly imprinted polymers (MIPs) are synthetic tailor-made polymers with high selectivity towards a particular substance (template). An MIP using vinblastine (VLB) as the template molecule was synthesized and characterized. The presence of monomer-template complexes in a non-covalent way was confirmed by UV-vis spectrometry analysis. The polymerization was performed using methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent, and toluene as the porogenic solvent by a thermo-polymerization method. The characterization of the obtained MIP was evaluated by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. It was observed that the morphology of the MIP was more porous and rough, and the surface area had a significant increase compared with that of the non-imprinted polymer (NIP). This MIP was used as the sorbents of solid-phase extraction (SPE) to assess the selectivity of the MIP after optimization of the SPE protocol. VLB was specifically adsorbed on the MIP cartridge, while to vincristine (VCR), the chemical analog of VLB, almost no selective binding appeared. On the basis of the results, Catharanthus roseus extract was applied to the MIP cartridge for investigating its capability to extract VLB from the plant extract, and the capacity of the MIP cartridge was also evaluated. It was shown that the MIP could effectively enrich VLB from C. roseus extract and the recovery amounted to 93.8%. The solvents dissolving the samples had significant influence on the capacity of the MIP cartridge; it was 750 μg/g in toluene, 625 μg/g in chloroform, and 250 μg/g in methanol.  相似文献   

14.
This paper describes the fabrication of a sensor for 1-hydroxypyrene (1-OHP) based on a screen-printed carbon electrode (SPCE) modified with a molecularly imprinted polymer (MIP); 1-OHP was chosen as a model metabolite of polyaromatic hydrocarbons (PAHs). It was shown that 1-OHP could be readily oxidised at a plain SPCE and the electrochemical mechanism was found to involve an ECE (electron transfer-chemical reaction-electron transfer) process. The MIP for 1-OHP was prepared using only divinylbenzene (DVB) and styrene as monomers and the binding was only based on hydrophobic interactions. Batch binding studies revealed that optimum uptake of 1-OHP by the MIP occurred from solutions containing 35% water in methanol. Selectivity of the binding sites in the MIP was examined by performing uptake studies in the same solution containing either phenol or 1-naphthol; the specific binding of 1-OHP was twenty times greater than the former and five times greater than the latter. Preliminary calibration studies were performed with the MIP-SPCE using a two-step approach; accumulation was carried out in 35% water in methanol followed by measurement in 50% methanol-0.025 mol dm(-3) phosphate buffer pH 12. This two-step non-competitive affinity assay gave encouraging results and indicated potential for use in pollution studies.  相似文献   

15.
为了在含水介质中进行有效印迹,本研究中以双甲基丙烯酰-β-环糊精(BMA-β-CD)和2-(二乙基胺基)乙基甲基丙烯酸酯(DEAEM)为功能单体制备了胆酸印迹聚合物MIP1,并用平衡结合实验研究了MIP1在含水介质中对模板分子的识别能力。结果表明,MIP1比单独以BMA-β-CD或DEAEM为功能单体制备的印迹聚合物MIP2和MIP3,显示出对模板分子更好的选择性结合能力。MIP1的特异性吸附量ΔCP为38.81μmol/g,印迹因子IF为2.46。研究表明,在含水介质中,利用模板分子与功能单体之间的疏水作用和离子作用是提高印迹聚合物分子识别能力的关键。研究还表明,在识别过程中,疏水作用在驱动分子进入印迹孔穴时起重要作用。  相似文献   

16.
In this paper we describe the synthesis of a molecularly imprinted polymer (MIP) by precipitation polymerisation, with barbital as the template molecule, and the application of the barbital MIP as a molecularly selective sorbent in the solid-phase extraction (SPE) of barbiturates from human urine samples. The MIP was synthesised by precipitation polymerisation using 2,6-bis-acrylamidopyridine as the functional monomer and DVB-80 as the cross-linking agent. The spherical MIP particles produced were 4.2 ± 0.4 μm in diameter; a non-imprinted control polymer (NIP) in bead form was 4.8 ± 0.4 μm (mean±standard deviation) in diameter. The particles were packed into a solid-phase extraction cartridge and employed as a novel sorbent in a molecularly imprinted solid-phase extraction (MISPE) protocol. The MIP showed high selectivity for the template molecule, barbital, a feature which can be ascribed to the high-fidelity binding sites present in the MIP which arose from the use of 2,6-bis-acrylamidopyridine as the functional monomer. However, the MIP also displayed useful cross-selectivity for other barbiturates besides barbital. For real samples, the MIP was applied for the extraction of four barbiturates from human urine. However, due to the high urea concentration in this sample which interfere the proper interaction of barbiturates onto the MIP, a tandem system using a commercially available sorbent was developed.  相似文献   

17.
We have prepared a hydrophilic molecularly imprinted polymer (MIP) for the hydrophobic compound bisphenol A (BPA) in aqueous solution using 3-acrylamido-N,N,N-trimethylpropan-1-aminium chloride (AMTC) as the functional monomer. Under redox-polymerization conditions, BPA forms an ion-pair with AMTC, which was confirmed by 1H-NMR titration. The imprinting effect in aqueous solution was evaluated by comparison of this material with the corresponding non-imprinted polymer (NIP) and with a control polymer (CP) bearing no AMTC. The MIP showed the highest activity among the three polymers, and the imprinting factors as calculated from the amount of BPA bound to the MIP divided by the amounts bound to NIP and CP, respectively, are 1.8 and 6.0. The MIP was selective for BPA in aqueous solution, while structurally related compounds are not recognized. Such a selectivity for a hydrophobic compound is rarely observed in aqueous medium because non-specific binding of BPA inevitably leads to hydrophobic interaction.
Figure
A hydrophilic molecularly imprinted polymer (MIP) for bisphenol A (BPA) recognition was prepared in aqueous solution. The obtained MIP (BPA-MIP) showed good selectivity under aqueous conditions  相似文献   

18.
A new concept for the preparation of selective sorbents with high flow path properties is presented by embedding molecularly imprinted polymers (MIPs) into various macroporous gels (MGs). A MIP was first synthetized with 17beta-estradiol (E2) as template for the selective adsorption of this endocrine disrupter. The composite macroporous gel/MIP (MG/MIP) monoliths were then prepared at subzero temperatures. Complete recovery of E2 from a 2 microg/L aqueous solution was achieved using the polyvinyl alcohol (PVA) MG/MIP monoliths whereas only 49-74% was removed with non-imprinted polymers (when no template was used). The PVA MG/MIP monolith columns were operated at almost 10 times higher flow rate (50 mL/min) compared to the MIP columns with operation flow rate of 1-5 mL/min. The possibility for processing the particulate containing wastewater effluents at high flow rates with selectivity on E2 removal, as well as the easy preparation of the monoliths, make the macroporous MG/MIP systems attractive and robust sorbents for the clean up of water from endocrine disrupting trace contaminants.  相似文献   

19.
The extraction device used in rotating-disk sorptive extraction consists of a Teflon disk in which a sorptive phase is fixed on one of its surfaces. Depending on the configuration, the rotation axis of the disk device can be either perpendicular or parallel to its radius, giving rise to two different mass transfer patterns when rotating-disk sorptive extraction is applied in liquid samples. In the perpendicular case (configuration 1), which is the typical configuration, the disk contains an embedded miniature stir bar that allows the disk rotation to be driven using a common laboratory magnetic stirrer. In the parallel case (configuration 2), the disk is driven by a rotary rod connected to an electric stirrer. In this study, triclosan and its degradation product methyl triclosan were used as analyte models to demonstrate the significant effect of the rotation configuration of the disk on the efficiency of analyte mass transfer from water to a sorptive phase of polydimethylsiloxane. Under the same experimental conditions and at a rotation velocity of 1,250 rpm, extraction equilibrium was reached at 80 min when the disk was rotated in configuration 1 and at 30 min when the disk was rotated in configuration 2. The extraction equilibration time decreased to 14 min when the rotation velocity was increased to 2,000 rpm in configuration 2. Because the rotation pattern affects the mass transfer efficiency, each rotation configuration was characterized through the Reynolds number; Re values of 6,875 and 16,361 were achieved with configurations 1 and 2, respectively, at 1,250 rpm.  相似文献   

20.
A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium for electrochemical detection of fenbendazole. The limit of detection was 1.9 × 10−7 mol L−1 (57 μg L−1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission (500 μg kg−1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed. The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton–Robinson Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate of 2.0 mL min−1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 μg kg−1. Results obtained for ten different liver samples yielded mean recoveries of (95 ± 12)% and (96 ± 11)% for the upper and lower concentration level, respectively.  相似文献   

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