Preparation and Evaluation of Histamine Imprinted Polymer as a Selective Sorbent in Molecularly Imprinted Solid-Phase Extraction Coupled with High Performance Liquid Chromatography Analysis in Canned Fish

A series of molecularly imprinted polymers (MIPs) were prepared against histamine. Different template/monomer ratios were applied to optimize the imprinting condition. Methacrylic acid (MAA) as a functional monomer and Chloroform as a solvent were applied in polymerization process. The binding properties of MIPs were studied in comparison with a blank non-imprinted polymer. The optimized polymer, with a histamine/MAA ratio of 1/4, was selected as a sorbent in molecularly imprinted solid-phase extraction (MISPE) of histamine from canned fish. Scatchard analysis of MIP-histamine interactions revealed two types of binding sites for MIP: high affinity (K_D?=?11.11 μM) and low affinity (K_D?=?333.3 μM). The MISPE procedure was calibrated and a recovery of 76.5–97.6 % was obtained. The intra-and inter-day precision values were less than 5.70 % and 10.1 %, respectively. The selectivity of MISPE for histamine was also studied in comparison with some other structurally similar amines, which could be simultaneously present in canned fish. The performance of the imprinted polymer was examined and the results indicated that its good selectivity and affinity for histamine was very promising. Therefore, the proposed calibrated method could be applied in selective extraction and analysis of histamine in canned fish.     

Occurrence of estrogenic compounds in and removal by a swine farm waste treatment plant

The total estrogenic activity of the wastewater from a swine farm in Japan was quantitatively characterized, and the compounds responsible for the estrogenic activity were identified and quantified. The wastewater treatment process consisted of a series of an up-flow anaerobic sludge blanket (UASB) and a trickling filter. Samples were collected at each treatment step, and the total estrogenic activity was determined by use of an in vitro gene expression assay (MVLN; MCF-7 human breast cancer cell stably transfected with the pVit-tk-LUC receptor plasmid). Individual estrogenic compounds were identified and quantified using liquid chromatography-mass spectrometry (LC/MS) and liquid chromatography-tandem mass spectrometry (LC/ MS/MS). To further identify the compounds contributing to the estrogenic activity in the wastewater, the sample extracts were fractionated into 12 fractions (fractions 1-12) by HPLC. The rate of removal of estrogenic activity between the effluent and the influent was greater than 97%. The trickling filter removed the majority of the estrogenic activity. The removal rates of specific estrogenic compounds ranged from 44 to 99%. Estrogenic activity was detected mainly in the fractions containing estrone (El), 17beta-estradiol (betaE2), 17alpha-estradiol (alpha E2), estriol (E3), bisphenol A (alphaPA), and equol (EQ0). The ratios of betaE2-EQc (betaE2 equivalents derived from chemical analysis) to betaE2-EQB (betaE2 equivalent derived from bioassay) in the 12 fractions collectively were contributed by El (17-30%), betaE2 (23-30%), acE2 (<1%), E3 (1-2%), BPA (<1%), and EQO (2-3%) in the influent and El (16-37%), PE2 (<1-7%), alphaE2 (<1%), E3 (<1-3%), BPA (<1%), and EQO (<1%) in the effluent. The compounds responsible for most of the estrogenic activity measured in the bioassay were natural estrogens such as El and betaE2.     

沉淀聚合法制备葛根素印迹微球及其固相萃取葛根粉

以葛根素为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂沉淀聚合法制备葛根素印迹聚合物微球。用扫描电镜观察微球形貌,静态吸附法测试聚合物的吸附行为。探讨分子印迹聚合物（molecularly imprinted polymers,MIPs）对葛根粗提液中葛根素的吸附、解吸附及固相萃取效能。结果表明,优化的葛根素MIP3对纯模板的静态吸附量达37.9 mg/g;对粗提液中目标化合物的吸附率为（96.3±1.81）%,以水、甲醇-醋酸（9∶1,V/V）及50%甲醇溶液为洗脱剂的单次解吸率为27%～34%,用水从MIP3上解吸出的总溶液经脱除溶剂后,所获粗品葛根素含量最高,达（37.4±2.87）%。在优化条件下,通过MIP3固相萃取葛根粗提液,葛根素回收率达71.6%,产品纯度高于75%。     

Selective trace analysis of sulfonylurea herbicides in water and soil samples based on solid-phase extraction using a molecularly imprinted polymer

A molecularly imprinted polymer (MIP) was synthesized using the herbicide metsulfuron-methyl (MSM) as a template, 2-(trifluoromethyl)acrylic acid as a functional monomer, divinylbenzene as a cross-linker, and dichloromethane as a porogen. This polymer was used as a solid-phase extraction material for the quantitative enrichment of five sulfonylureas (nicosulfuron, thifensulfuron-methyl, metsulfuron-methyl, sulfometuron-methyl, and chlorsulfuron) in natural water and soil samples and off-line coupled to a reversed-phase HPLC/diode array detection (HPLC/DAD). Washing solvent was optimized in terms of kind and volume for removing the matrix constituents nonspecifically adsorbed on the MIP. It has been shown that the nonspecific binding ability of the sulfonylureas to the polymer largely increased along with increasing the concentration of Ca2+ ions in the water sample, whereas complexation of divalent ions with EDTA eliminated this interference completely. The stability of MIP was tested by consecutive percolation of water sample, and it was shown that the performance of the MIP did not vary even after 200 enrichment and desorption cycles. Recoveries of the five sulfonylureas extracted from 1 L of tap water and surface water samples such as river water and rainwater at a 50 ng/L spike level were not lower than 96%. The recoveries of sulfonylureas extracted from 10-g soil sample at the 50 microg/kg level were in the range of 71-139%. Depending on the particular compound, the limit of detection varied from 2 to 14 ng/L in water and from 5 to 12 microg/kg in soil samples. The MIP was also compared with a commercially available C-18 column and an immunoaffinity support with encapsulated polyclonal anti-MSM antibodies in sol-gel glass.     

Convenient solid phase extraction of cephalosporins in milk using a molecularly imprinted polymer

In this paper, a molecularly imprinted polymer (MIP) for cephalosporin molecules (cephalexin (CFL) and cephapirin (CFP)), was prepared by non covalent molecular imprinting approach and applied to solid phase extraction (SPE). For MIP synthesis, a tributylammonium cefadroxil salt (TBA-CFD) was used as template with methacrylic acid and ethylene glycol dimethacrylate as monomer and cross-linker, respectively, in acetone-methanol 92/8 (v/v) mixture. The selectivity of MIP versus non imprinted polymer (NIP) was confirmed for CFL, CFD and CFP in standard solutions as well as in milk samples. The efficiency of the synthesized MIP was evaluated by means of the application of the proposed MIP-SPE procedure to spiked milk samples previous to the HPLC method for the detection of cephalosporins. The MIP-SPE recoveries were higher than 60% for the three target analytes in spiked milk.     

分子印迹技术在真菌毒素检测中的应用

旨在综述分子印迹技术在真菌毒素检测中的应用,介绍分子印迹技术的原理、聚合物制备的过程以及评价聚合物性能的指标,并介绍粮食中常见真菌毒素：玉米赤霉烯酮、赭曲霉毒素A、脱氧雪腐镰刀菌烯醇、黄曲霉毒素分子印迹聚合物的制备及其在固相萃取、生物传感器中检测真菌毒素的应用,分析分子印迹技术在真菌毒素检测领域的前景以及需要解决的问题。     

花椒麻味物质替代模板分子印迹聚合物的制备

为制备对花椒麻味物质具有特异性吸附效果的分子印迹聚合物,优化其制备条件,采用紫外光谱法研究甲基丙烯酸、丙烯酰胺、2-乙烯基吡啶与替代模板分子的作用强度、最佳物质的量比;以乙二醇二甲基丙烯酸酯为交联剂,乙腈为溶剂,偶氮二异丁腈为引发剂,采用本体聚合的方法在不同条件下制备多种分子印迹聚合物;从中选出对花椒麻味物质印迹效果最优的分子印迹聚合物,并用其分离纯化花椒萃取液中的花椒麻味物质,高效液相色谱检测结果表明,最优分子印迹聚合物对花椒麻味物质的吸附量为（14.64±0.80）mg/g,洗脱液中花椒麻味物质占总峰面积的比例比在花椒萃取液中提高了约21.95%,即该替代模板分子印迹聚合物对花椒麻味物质具有较好的特异性吸附效果。     

Enhanced photocatalytic degradation and selective removal of nitrophenols by using surface molecular imprinted titania

Poor selectivity of titania (TiO2) photocatalysis is unfavorable to photocatalytic removal of highlytoxic low-level organic pollutants in polluted waters in the presence of other less toxic high-level pollutants. A new strategy of increasing this selectivity is the surface modification of TiO2 via coating a thin layer of molecular imprinted polymer (MIP), which provides molecular recognition ability toward the template molecules. By using 2-nitrophenol and 4-nitrophenol as target pollutants, MIP-coated TiO2 photocatalysts were prepared via surface molecular imprinting and were observed to have high activity and selectivity toward the photodegradation of the targets. In the presence of bisphenol A (50 mg L(-1)) as a nontarget pollutant, the apparent rate constant for the photodegradation of the target 2-nitrophenol and 4-nitrophenol (1.8 mg L(-1)) over the corresponding MIP-coated TiO2 was 10.73 x 10(-3) and 7.06 x 10(-3) min(-1), being 2.46 and 4.61 times of that (4.36 x 10(-3) and 1.53 x 10(-3) min(-1)) over neat TiO2, respectively. The enhanced photocatalytic selectivity was increased when the concentration of the target was decreased and/or when the difference in both the chemical structure and molecule size between the target and nontarget molecules was increased. The increased selectivity was mainly attributed to the special interaction between the target molecules and the footprints polymer via the functional groups (-OH and -NO2).     

基于硼亲和策略的分子印迹技术研究进展

基于硼酸配基与顺式二羟基化合物的可逆共价结合,硼亲和分子印迹技术具有印迹效率高、亲和力强以及pH调控的结合与释放等优势,被广泛应用于含有顺式二醇配基分子的分离与富集。文章介绍了硼亲和分子印迹技术在核苷酸、糖、糖蛋白、细胞和细菌识别及富集中的应用,并对其发展前景进行了展望。     

农药氯氰菊酯的分子印迹聚合物的合成及其结合性能研究

为了制备特异性强、吸附效果好的分析材料,本实验采用分子印迹技术,以农药氯氰菊酯为模板分子,甲基丙烯酸 (MAA) 为功能单体,乙二醇二甲基丙烯酸酯 (EDMA) 为交联剂,合成了对氯氰菊酯具有高度选择性的分子印迹聚合物(MIP)。通过平衡吸附实验,评价了其对氯氰菊酯的亲和力和选择性。结果表明,与空白MIP相比,氯氰菊酯MIP对其表现出较高的亲和力。Scatchard 分析表明,在MIP中存在对氯氰菊酯有不同亲和力的两类作用位点,其中高亲和力结合位点的离解常数Kd为3.604×10-4mol/L,最大表观吸附量Qmax为53.045μmol/g,低亲和力结合位点的离解常数Kd为1.8015×10-3mol/L,最大表观吸附量为116.61μmol/g。氯氰菊酯MIP上有两个不同性质的结合位点,它对模板分子氯氰菊酯具有一定的选择性和识别能力。     

Solid-Phase Extraction of Florfenicol from Meat Samples by a Newly Synthesized Surface Molecularly Imprinted Sol–Gel Polymer

A new molecularly imprinted polymer (MIP) as a solid-phase sorbent for selective extraction of florfenicol (FF) was prepared by combination of the surface molecular imprinting technique with the sol–gel process. The FF-imprinted silica sorbent was prepared using FF as template, 3-aminopropyltriethoxysilane as functional monomer and tetraethoxysilicate as cross-linker on the silica gel support. The non-imprinted silica (NIP) was synthesized in the same way without addition of FF. The MIP was evaluated as a sorbent in column extraction approach for extraction of FF from aqueous solutions followed by spectrofluorometric determination. The influence of certain variables including the sample pH, the sample volume, the sample flow rate, the type of eluent, and its flow rate on the extraction efficiency of FF was assessed. The prepared FF-MIP silica sorbent showed higher adsorption capacity (64.9 mg g^?1) and significant selectivity than the corresponding NIP (11.5 mg g^?1). The FF-MIP-based solid phase extraction method was successfully applied to the separation and determination of FF from fish and chiken meat samples under the optimized extraction conditions.     

荧光磁性表面分子印迹聚合物对柚皮苷的荧光偏振检测

采用荧光磁性表面分子印迹法对柚皮苷进行荧光偏振检测。该方法以二氧化硅包裹的磁性颗粒为基质,甲基丙烯酸和丙烯酰胺为单体,并用异硫氰酸荧光素标记,得到同时具有荧光和磁性的表面分子印迹聚合物。并采用荧光偏振法和紫外分光光度法对制备的聚合物结合能力进行检测。通过与比较2种检测方法可知荧光偏振法更为灵敏,检出限为0.1?mg/L。最后对番茄酱中含有的柚皮苷进行回收率检测,回收率达到81.3%以上。说明采用荧光磁性表面分子印迹法对食品中柚皮苷可快速、高效地检测。     

Screening for estrogen residues in calf urine: comparison of a validated yeast estrogen bioassay and gas chromatography-tandem mass spectrometry.

Within the European Union, the control for residues of illegal hormones in food-producing animals is based on urine analysis for a few target analytes using gas chromatography/mass spectrometry and/or liquid chromatography-tandem mass spectrometry. Recently, we developed a robust yeast bioassay screening tool for estrogens, which was validated as a qualitative screening method in accordance with EC decision 2002/657/EC. In this study, we present long-term performance data and a comparison of urine data obtained with this bioassay, and data from an established gas chromatography-tandem mass spectrometry (GC/MS/MS) confirmatory analysis method. More than 120 calf urine samples from a controlled reference experiment were analysed using both protocols. According to the GC/MS/MS method, only the natural estrogens 17alpha-estradiol and estrone were present in the non-compliant samples. The bioassay was less sensitive than GC/MS/MS for the relatively weak estrogenic compound 17alpha-estradiol, in accordance with expectations. Assuming that application of the mass spectrometric method is considered beyond reasonable doubt, the bioassay performed very well: only 5.6% of the calf urine samples found compliant in GC/MS/MS were screened false suspect in the bioassay screening method. The bioassay results of non-compliant urine samples under routine conditions were as predicted, taking into account the relative estrogenicity of the natural estrogens 17alpha-estradiol and estrone vs. 17beta-estradiol. Only one sample was screened false negative for 17alpha-estradiol and estrone. Application of this fast and simple estrogen bioassay in routine surveillance and control can significantly reduce GC/MS/MS sample workload and allow higher percentages of animals to be screened for potential hormone abuse.     

Synthesis and Evaluation of Molecularly Imprinted Polymers (MIP) with Affinity for the Polypeptide Nisin

The method of hierarchical imprinting was used for the first time in order to synthesize polymers with a high affinity for nisin. The concept of this approach is demonstrated by filling the pores of silica particles, which contain immobilized peptidic templates, with a mixture of monomers/initiator, followed by polymerization and subsequent dissolution of the silica template. This method leaves imprinted polymers with binding sites located at the surface that are capable of recognizing larger molecules with the same immobilized epitope. The results of the high-performance liquid chromatography analyses illustrate that the highest retention factors and imprinting factors of nisin on nisin C-terminal analogously imprinted polymers could be obtained with acetonitrile/water mixtures containing more than 80% water. Furthermore, nisin was strongly retained on polymers that were imprinted with a longer amino acid sequence because of better sterical accessibility of the binding sites for the C terminus of nisin. The retention of nisin (k = 21.65) under aqueous elution conditions results from selective ionic interactions and hydrophobic interactions. Furthermore, the polymers exhibited selectivity for the template Lys-Ala and the structurally related dipeptide Ala-Lys. The results of the present work show that these hierarchically imprinted polymers could be used for the chromatographic separation of the polypeptide nisin in aqueous solutions.     

乙氧酰胺苯甲酯表面分子印迹聚合物的制备与吸附特性

合成功能单体N,O-双异丁烯酰乙醇胺（N,O-bismethacryloyl ethanolamine,NOBE）,采用表面分子印迹技术,以硅胶为载体,乙二醇二甲基丙烯酸酯（ethylene glycol dimethacrylate,EGDMA）为交联剂,制备乙氧酰胺苯甲酯（ethopabate,ETP）分子印迹聚合物（molecularly imprinted polymers,MIPs）。采用正交试验方法,对ETPNOBE物质的量比、ETP-EGDMA物质的量比和致孔剂种类3 个因素进行考察,结果表明：3 个影响因素主次顺序为致孔剂种类＞ETP-NOBE物质的量比＞ETP-EGDMA物质的量比;当致孔剂为乙腈、ETP-NOBE-EGDMA的物质的量比为1∶2∶20时,所制备的ETP-MIPs印迹效果最佳。Scatchard模型研究发现存在两类结合位点,高亲和位点与低亲和位点的平衡离解常数Kd和最大表观结合量Qmax分别为Kd1=1.608 μg/mL,Qmax1=1.101 μg/mg;Kd2=0.109 μg/mL,Qmax2=0.172 μg/mg。     

沙拉沙星分子印迹聚合物的制备及其性能研究

以沙拉沙星为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用本体聚合制备沙拉沙星的分子印迹聚合物。通过振荡吸附实验对模板分子和功能单体的比例进行优化。印迹聚合物和空白聚合物的等温吸附线表明,印迹聚合物形成的孔穴对沙拉沙星的吸附量高于空白聚合物。在吸附过程中模板分子沙拉沙星与印迹聚合物形成两种结合位点,两种结合位点的解离常数分别为0.321μg/mL和1.577μg/mL,对沙拉沙星最大表观吸附量分别为1.249mg/g和3.222mg/g。吸附动力学实验结果显示聚合物对沙拉沙星的吸附在7h达到平衡,选择性试验表明印迹聚合物对沙拉沙星具有较好的吸附特性。     

Ultrasound-induced destruction of low levels of estrogen hormones in aqueous solutions

The removal of estrogen hormones from water and wastewater is of importance due to their adverse effects toward ecosystems and potential risks to human health. The ultrasound-induced destruction of estrogen compounds in aqueous solutions is studied in a batch reactor using a 1.1 W/mL sonication unit and in a continuous flow reactor using a 2.1 W/mL sonication unit. The estrogen compounds of interest are 17alpha-estradiol, 17beta-estradiol, ethinyl estradiol, estrone, equilin, gestodene, levonorgestrel, and norgestrel. Effects of process variables such as temperature, pH, and pressure are examined. The degradation of estrogens follows pseudo first-order kinetics. The reaction likely takes place in the interfacial region where supercritical environment is produced upon cavity implosion and in the bulk solution with radical species. Low solution pH is more favorable for destruction of estrogens. A kinetic degradation model is developed to predict the destruction of estrogen compounds. Low solution temperature shows favorable destruction of estrogens. Increasing the fluid pressure is detrimental to reaction efficiency.     

表面印迹法制备链霉素分子印迹聚合物及其性能研究

利用硅胶颗粒为基质,在其表面接枝硅烷化试剂3-甲基丙烯酰氧基丙基三甲氧基硅烷(γ-MPS),进行硅烷化处理后,以链霉素为模板分子,甲基丙烯酸(MAA)为功能单体,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂在颗粒表面合成分子印迹层,制备得到链霉素分子印迹聚合物(MIPMs)和空白聚合物(NMIPMs),并采用静态平衡结合法借助高效液相色谱-蒸发光散射(HPLC-ELSD)研究了聚合物对模板分子链霉素的吸附能力、结合动力学和选择特性。扫描电镜观察和红外光谱分析结果表明表面印迹层已经成功合成;吸附实验结果表明,MIPMs比NMIPMs对链霉素具有更强的吸附特性和更好的选择性。     

4-甲基咪唑印迹聚合物的制备及其识别特性研究

利用分子印迹技术,制备用于4．甲基咪唑（4-MI）快速检测的高分子材料。以4-甲基咪唑为模板分子,α-甲基丙烯酸（MAA）为功能单体,偶氮二异丁腈（AIBN）为引发剂,乙二醇二甲基丙烯酸酯（EDMA）为交联剂,在乙腈中通过沉淀聚合制备rr分子印迹聚合物。用紫外分光光度法对4-MI与MAA的相互作用进行了分析,结果表明主客体主要存在形式为,1个4-MI为1个MAA所包围。利用Langmuir数学模型对吸附特性进行了分析,Scatchard图显示印迹聚合物的最大吸附量Bmax=221．14μmol／g和解吸常数KD=1．8mmol／L。同时对印迹聚合物的吸附选择性和吸附动力学进行了初步研究。     

Highly Selective Determination of Chrysoidine in Foods Through a Surface Molecularly Imprinted Sol–Gel Polymer Solid-Phase Extraction Coupled with HPLC

A highly selective determination method for chrysoidine, an industrial azoic dye banned in foods, was developed through a novel molecularly imprinted polymer (MIP) online solid-phase extraction coupled with high-performance liquid chromatography. The MIP was firstly synthesized by a surface molecular imprinting technique in combination with a sol–gel process and characterized by FT-IR and adsorption experiments. The MIP exhibited high selectivity and high adsorption capacity for chrysoidine and offered a fast kinetics for the adsorption and desorption of chrysoidine. A number of parameters, including the pH of loading solution, the sample loading flow rates, and eluting time of analyte, were carefully optimized to improve the extraction efficiency. Under the optimal experimental conditions, for a 50-mL sample solution, the enrichment factor was 279 and the detection limit (S/N?=?3) was 6 ng L^?1. The linear plots with r ²?>?0.99 were achieved over a range of 0.04–40 μg L^?1, and the peak area precision (relative standard deviation) for nine parallel determinations was below 6.32 %. This method was employed for quantitative determination of chrysoidine in oil bean curd, yellow croaker, and paprika with satisfactory recoveries (89.3–97.6 %).