具有高选择性吸附的表面分子印迹磁性纤维素微球的制备与性能

以纤维素和纳米Fe₃O₄为原料制得磁性纤维素微球, 在纤维素微球表面选择合适的模板分子, 以甲基丙烯酸、 丙烯酰胺和N,N'-亚甲基双丙烯酰胺为功能单体, 采用水溶液聚合法制得表面分子印迹磁性纤维素微球. 采用傅里叶变换红外光谱(FTIR)、 X射线衍射(XRD)和振动样品磁强计(VSM)等表征了分子印迹聚合物微球的结构. 以罗丹明B(RhB)为模板分子, 通过吸附动力学与吸附热力学实验研究了表面分子印迹磁性纤维素微球对RhB的吸附性能, 结果表明, 制备的表面分子印迹磁性纤维素微球对罗丹明B具有特异性识别作用, 饱和吸附量达到0.542 mg/mg, 吸附平衡时间为10 h左右. 表面分子印迹磁性纤维素微球大大降低了对吸附环境的依赖, 并可重复利用.     

加替沙星磁性表面分子印迹材料的制备及其识别特性的研究

以γ-(甲基丙烯酰氧)丙基三甲氧基硅烷( MPS)修饰的磁性二氧化硅( Fe3 O4@SuO2)为载体,加替沙星( GTFX)为模板分子,采用表面印迹法制备磁性表面分子印迹聚合物( M-MIPs)。用透射电镜( TEM)及磁化强度分析( VSM)对此聚合物进行了表征。吸附实验和Scatchard分析结果表明,M-MIPs中存在特异性和非特异性两类结合位点。 M-MIPs 和磁性非印迹聚合物( M-NIPs)对 GTFX 的最大吸附容量分别为35.1和23.13 mg/g。 M-MIPs对于环丙沙星(CPFX)、诺氟沙星(NFLX)、三聚氰胺(MEL)以及四环素(TC)的选择性系数k分别为2.43,5.18,6.61和12.99;M-MIPs相对M-NIPs的相对选择性系数k＇分别为2.09,1.95,3.15和2.43,表明M-MIPs对GTFX具有良好的特异性识别能力。将此表面印迹材料用于牛奶中GTFX的分离富集,采用高效液相色谱法检测,回收率大于91.5%。     

三聚氰胺磁性分子印迹聚合物材料的制备及性能表征

利用溶剂热法通过控制反应时间和温度制得了分散性好和磁性强的Fe3O4,并利用溶胶凝胶法制备得到包覆SiO2的磁性微球(Fe3O4@SiO2)。以三聚氰胺为模板分子,甲基丙烯酸(MAA)为单体,采用本体聚合法制备了磁性分子印迹聚合物(MMIPs)。通过静态吸附实验表明,MMIPs对三聚氰胺的饱和吸附量高达10.22μg/mg,是磁性非印迹聚合物(MNIPs)的1.62倍。粒子扩散模型、Elovich模型和动态吸附实验表明所制得的MMIPs有较好的吸附性能。     

不同热解温度下制备的磁性生物炭对罗丹明B的吸附性能

以水稻秸秆为原材料,采用一步磁化碳化法,于550、600、650和700℃下进行限氧裂解,制备出4种高效易分离的磁性生物炭(MBC-550、MBC-600、MBC-650和MBC-700)。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、比表面孔径分布分析仪(BET)和傅里叶变换红外光谱仪(FT-IR)对其理化性质进行了表征,探究了不同温度对其结构性质和吸附性能的影响。而后研究了MBC对罗丹明B(RhB)的吸附动力学、吸附等温线,并考察了pH值和金属阳离子(Na⁺、Fe³⁺、Mg²⁺和Cu²⁺)对吸附性能的影响。结果表明,随着热解温度升高,MBC的比表面积和孔容积增大,MBC的吸附性能受温度影响显著。在30℃时,4种不同热解温度制备的MBC对RhB的平衡吸附量分别为35.696、36.962、53.118和54.810 mg/g。4种MBC对RhB的吸附均符合伪二级动力学方程,表明MBC对RhB的吸附受多种因素影响;采用Langmuir与Freundlich方程对等温吸附结果进行拟合,吸附等温...     

羧甲基-β-环糊精功能化的四氧化三铁磁性纳米复合物对罗丹明B的吸附性能

基于S_N2取代反应制备了羧甲基-β-环糊精(CM-β-CD),采用层层组装法将其成功修饰在Fe₃O₄磁性纳米粒子表面(MNPs),得到了CM-β-CD功能化的磁性纳米复合物(CM-β-CD-MNPs),通过透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)及振动样品磁强计(VSM)等技术手段进行了表征,考察了其对染料罗丹明B(RhB)的吸附性能。 结果表明,CM-β-CD-MNPs呈球形,分散均匀,平均粒径为16 nm,饱和磁化率为54 emu/g,呈超顺磁性。 吸附动力学符合准二级动力学模型,且吸附1 h达到平衡。 吸附等温线符合Langmuir等温吸附模型,最大吸附量为135.1 mg/g。     

粉煤灰磁性吸附剂的制备及磷吸附机理

通过化学沉淀法制备了CMS@La_2O_3磁性磷吸附剂。结构及磁性表征显示,氧化镧较均匀的包覆在粉煤灰磁珠表面;样品的比磁化强度达20.35 emu·g~(-1),可实现高效磁分离。利用钼酸铵分光光度法对所得磁性吸附剂的磷吸附性能进行了试验研究。研究表明,其最高磷比饱和吸附量可达19.50 mg·g~(-1),吸附时间、pH值、共存阴离子等因素对磷吸附效果均具有显著影响。吸附动力学拟合表明,CMS@La_2O_3对含磷离子的吸附符合准二级动力学方程,以化学吸附为主,磁性吸附剂对含磷离子的吸附反应过程可由La_2O_3表面羟基化-离子交换模型解释。吸附磷后的CMS@La_2O_3吸附剂经处理后可多次循环使用。     

磁性壳聚糖去除水中腐殖酸的研究

采用高温水热法合成了磁性壳聚糖,并研究了其对水中腐殖酸(HA)的吸附、脱附行为。表征结果表明,磁性壳聚糖粒径大小为200～300nm,氨基含量1.29mmol·g-1,BET比表面积36.00m2·g-1,饱和磁化强度为38.78emu·g-1,易于磁性分离。HA在磁性壳聚糖上的吸附等温线可用Freundlich方程模拟,吸附动力学符合拟二级动力学方程。HA的吸附量随溶液pH值的升高而降低,随不同阳离子浓度增加而增加,不同类型的阳离子对HA吸附效果影响的大小顺序为:Ca2+Mg2+Na+K+。经5个脱附再生循环,磁性壳聚糖仍能保持79.8%的吸附量,表明该吸附剂再生性好,可循环使用。     

新型吸附剂的制备、表征及对罗丹明B的吸附研究

以向日葵秸秆为原料,采用氯化锌活化法制得秸秆活性炭。并对其进行扫描电镜(SEM)和比表面积测定表征分析,考察了活性炭对罗丹明B的最佳吸附条件、吸附热力学和吸附动力学行为。结果表明,向日葵秸秆活性炭对罗丹明B的吸附与Langmuir方程拟合良好,R~20.99,在323K时最大吸附量可达到666.67mg/g;该吸附过程遵循Lagergren准二级动力学模型。热力学研究表明,该吸附过程为自发进行的吸热过程。     

种子溶胀悬浮聚合法制备分子印迹聚合物微球

 以酪氨酸为印迹分子 ,甲基丙烯酸为功能单体 ,三羟甲基丙烷三甲基丙烯酸酯 (TRIM )为交联剂 ,采用种子溶胀悬浮聚合法在水溶液中制备了一系列分子印迹聚合物微球 (MIPMs)。利用扫描电镜 (SEM)对此微球的粒径大小、粒径分布、表面孔与孔径分布等进行了分析研究 ,探讨了影响其形貌的主要因素 ,并将所得微球用作固定相研究了其分子选择吸附性能。研究表明 ,种子溶胀悬浮聚合法能够制得单分散性较好的、表面带有微孔的分子印迹聚合物微球 ,且该微球呈现出较好的特异吸附性能。     

磁性珠状纤维素的性能表征

本文采用反相悬浮包埋技术制各了磁性珠状纤维素（magneticcellulosebead缩写MCB），并对MCB各方面的性能进行了全面的评价：湿态孔度高达80％以上，磁化率在10-3emu／g数量级，磁性铁分布均匀，且磁稳定性较高。     

Preparation of monodisperse magnetic surface molecularly imprinted polymers for selective recognition of lincomycin hydrochloride in milk

Monodisperse magnetic surface molecularly imprinted polymers (M-MIPs) with a specificity for lincomycin hydrochloride (LIN) were successfully prepared using surface-initiated atom transfer radical polymerization on the monodisperse magnetic polymer (vinylbenzylchloride/divinylbenzene) (Fe₃O₄/P_VBC/DVB) with LIN as a template molecule and 4-vinyl pyridine as the functional monomer. The Fe₃O₄ magnetic nanoparticles embedded itself in the micropores of polymer (P_VBC/DVB) by reversibly swelling adsorption method in which the pores of the polymer are swollen by the solvent, and then the Fe₃O₄ magnetic nanoparticles enter the pores, and as the solvent evaporates the pores of the polymer back to their original size, and Fe₃O₄ magnetic nanoparticles are left in the pores. The composition and magnetic properties of the polymer were characterized using scanning elemental microscopy analysis, X-ray diffraction, Surface element analysis and vibrating sample magnetometer analysis. The results of this study showed that the M-MIPs had good specific recognition ability for LIN. The imprinting factor is 3.72. The specific recognition capability of the polymers was affirmed by high performance liquid chromatography analysis. The spiked recovery was 94.3%–98.2% with RSD ≤ 3.7%, and the minimum detection limit is 15.0?ng/g (S/N?=?3) indicating that this material has application value in the pretreatment of complex samples.     

Selective separation of lambdacyhalothrin by porous/magnetic molecularly imprinted polymers prepared by Pickering emulsion polymerization

Porous/magnetic molecularly imprinted polymers (PM‐MIPs) were prepared by Pickering emulsion polymerization. The reaction was carried out in an oil/water emulsion using magnetic halloysite nanotubes as the stabilizer instead of a toxic surfactant. In the oil phase, the imprinting process was conducted by radical polymerization of functional and cross‐linked monomers, and porogen chloroform generated steam under the high reaction temperature, which resulted in some pores decorated with easily accessible molecular binding sites within the as‐made PM‐MIPs. The characterization demonstrated that the PM‐MIPs were porous and magnetic inorganic–polymer composite microparticles with magnetic sensitivity (M_s = 0.7448 emu/g), thermal stability (below 473 K) and magnetic stability (over the pH range of 2.0–8.0). The PM‐MIPs were used as a sorbent for the selective binding of lambdacyhalothrin (LC) and rapidly separated under an external magnetic field. The Freundlich isotherm model gave a good fit to the experimental data. The adsorption kinetics of the PM‐MIPs was well described by pseudo‐second‐order kinetics, indicating that the chemical process could be the rate‐limiting step in the adsorption of LC. The selective recognition experiments exhibited the outstanding selective adsorption effect of the PM‐MIPs for target LC. Moreover, the PM‐MIPs regeneration without significant loss in adsorption capacity was demonstrated by at least four repeated cycles.     

亲水性含环氧基磁性聚合物微球的制备与性能表征

选择甲酰胺作磁性Fe3O4微晶的分散剂,通过设计反相悬浮聚合体系,合成了粒径分布窄、球状亲水性含环氧基磁性聚合物(MGM).利用扫描电子显微镜(SEM)、红外光谱(FT-IR)、X射线粉末衍射仪(XRD)、振动样品磁强计(VSM)和低温N2吸附以及化学分析方法对聚合物进行了性能表征.结果表明,合成的MGM呈球形,且粒度分布较窄,粒径为0.13~0.28 mm的粒子占91%;甲酰胺分散Fe3O4,微晶表面的亲水性进一步增强,单体甲基丙烯酸缩水甘油酯和N,N′-亚甲基双丙烯酰胺交联共聚生成的胶粒能够包埋Fe3O4微晶形成胶核,胶核聚集形成均匀、稳定的MGM微球.MGM中Fe3O4含量为6.17%时,比饱和磁化强度σs达6.5 emu/g;其比表面积、平均孔径和孔容分别为117.6 m2/g,15.6 nm和0.46 cm3/g,表面环氧基团含量为0.53 mmol/g.MGM借助自身的活性环氧基团在十分温和的条件下共价偶联青霉素酰化酶(penicillin G acylase EC 3.5.1.11,简称PGA),制备的固定化酶在37℃下催化水解青霉素G钾生成6-氨基青霉烷酸(6-APA)的表观活性达502IU/g,并且在使用过程中没有出现磁聚集现象.     

Facile preparation of magnetic molecularly imprinted polymers for the selective extraction and determination of dexamethasone in skincare cosmetics using HPLC

Dexamethasone‐imprinted polymers were fabricated by reversible addition–fragmentation chain transfer polymerization on the surface of magnetic nanoparticles under mild polymerization conditions, which exhibited a narrow polydispersity and high selectivity for dexamethasone extraction. The dexamethasone‐imprinted polymers were characterized by scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, energy dispersive spectrometry, and vibrating sample magnetometry. The adsorption performance was evaluated by static adsorption, kinetic adsorption and selectivity tests. The results confirmed the successful construction of an imprinted polymer layer on the surface of the magnetic nanoparticles, which benefits the characteristics of high adsorption capacity, fast mass transfer, specific molecular recognition, and simple magnetic separation. Combined with high‐performance liquid chromatography, molecularly imprinted polymers as magnetic extraction sorbents were used for the rapid and selective extraction and determination of dexamethasone in skincare cosmetic samples, with the accuracies of the spiked samples ranging from 93.8 to 97.6%. The relative standard deviations were less than 2.7%. The limit of detection and limit of quantification were 0.05 and 0.20 μg/mL, respectively. The developed method was simple, fast and highly selective and could be a promising method for dexamethasone monitoring in cosmetic products.     

Preparation and surface modification of magnetic poly(methyl methacrylate) microspheres

~~Preparation and surface modification of magnetic poly(methyl methacrylate) microspheres~~     

Preparation of magnetic molecularly imprinted polymers by atom transfer radical polymerization for the rapid extraction of avermectin from fish samples

A novel and highly efficient approach to obtain magnetic molecularly imprinted polymers is described to detect avermectin in fish samples. The magnetic molecularly imprinted polymers were synthesized by surface imprinting polymerization using magnetic multiwalled carbon nanotubes as the support materials, atom transfer radical polymerization as the polymerization method, avermectin as template, acrylamide as functional monomer, and ethylene glycol dimethacrylate as crosslinker. The characteristics of the magnetic molecularly imprinted polymers were assessed by using transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, vibrating sample magnetometry, X‐ray diffraction, and thermogravimetric analysis. The binding characteristics of magnetic molecularly imprinted polymers were researched through isothermal adsorption experiment, kinetics adsorption experiment, and the selectivity experiment. Coupled with ultra high performance liquid chromatography and tandem mass spectrometry, the extraction conditions of the magnetic molecularly imprinted polymers as adsorbents for avermectin were investigated in detail. The recovery of avermectin was 84.2–97.0%, and the limit of detection was 0.075 μg/kg. Relative standard deviations of intra‐ and inter‐day precisions were in the range of 1.7–2.9% and 3.4–5.6%, respectively. The results demonstrated that the extraction method not only has high selectivity and accuracy, but also is convenient for the determination of avermectin in fish samples.     

Synthesis of magnetic chelator for high-capacity immobilized metal affinity adsorption of protein by cerium initiated graft polymerization

A novel magnetic chelator with high adsorption capacity of protein by immobilized metal affinity adsorption was prepared by cerium (IV) initiated graft polymerization of tentacle-type polymer chains with iminodiacetic acid (IDA) chelating group on magnetic particles with hydroxyl groups. The micron-sized magnetic poly(vinyl acetate-divinylbenzene) (PVAc-DVB) particles were prepared by a modified suspension polymerization in the presence of oleic acid-coated magnetite nanoparticles and subsequently modified by ester exchange reaction to introduce functional hydroxyl groups. Bovine hemoglobin (BHb) was selected as a model protein to investigate the adsorption capacity of these magnetic particles. The magnetic particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), superconducting quantum interference device (SQUID) magnetometry, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and X-ray diffraction (XRD). The results showed that the magnetic particles had an average size of 5 microm and superparamagnetism with saturation magnetization of 20.0 emu/g at room temperature. The protein adsorption indicated that the graft polymerization of tentacle type polymer chains on the magnetic particles could produce magnetic adsorbents with high adsorption capacity (1428.21 mg/g) and low nonspecific adsorption of protein. The magnetic particles with grafted tentacle polymer chains have potential application in large-scale affinity separation of proteins.     

安定分子印迹聚合物的制备及应用

以安定为模板分子,通过本体聚合和沉淀聚合的方法合成了分子印迹聚合物材料,考察了交联剂、致孔剂及温度等条件对聚合物材料性能的影响。电镜扫描图片显示本体聚合得到的聚合物呈不规则形状,而沉淀聚合得到的则是微球颗粒,形状规则。吸附实验表明,聚合物微球对安定的最大吸附量约为130μg/g,对奥沙西泮和硝西泮的吸附量约为110μg/g,对安定类化合物具有较高的吸附性能和选择性。通过对比合成现象和聚合物性能,最终选用以DVB为交联剂、乙腈为致孔剂合成的聚合物微球为固相萃取材料填充固相萃取小柱,从饲料及猪尿样品中选择性地分离、富集痕量安定类药物。结合高效液相色谱法检测,奥沙西泮、硝西泮和安定3种药物在0.1～20 mg/L范围内线性良好,相关系数为0.999 6～0.999 9,检出限(S/N=3)为0.03～0.08 mg/L,加标回收率为66%～79%。该方法为安定类药物的检测提供了一种新途径。     

Preparation of Surface-Imprinted Polymer Magnetic Nanoparticles with Miniemulsion Polymerization for Recognition of Salicylic Acid

Molecular surface-imprinted polymers nanoparticles encapsulating magnetite modified with oleic acid, for recognition of salicylic acid was prepared by three-step miniemulsion polymerization. The important factors including polymerization process, solvents, miniemulsifying approaches, and co-stabilizer have been investigated to obtain magnetic molecular imprinting polymers (MMIPs) nanoparticles (NPs) with high saturation magnetization (Ms), regular morphology, and good monodispersion. The results showed that the amount of magnetite encapsulated in MMIPs NPs was 43.4 wt% and Ms was 33.584 emu/g. Thus, MMIPs NPs could be separated easily within 2 minutes by an external magnetic field. The transmission electron microscope (TEM) showed MMIPs NPs were of regular sphere with core-shell structure, where magnetite NPs were uniformly encapsulated in homogeneous polymer shells. The average diameter of MMIPs NPs was 98 nm with RSD of 6.6%. Good recognition and high loading of target molecule were achieved by MMIPs NPs in batch rebinding tests.