采用新型分子表面印迹技术构建手性空穴实现对氨基酸对映体识别拆分的研究

通过γ-(甲基丙烯酰氧)丙基三甲氧基硅烷的媒介, 在溶液聚合体系中, 采用“接出”(“graft from”)法将功能单体甲基丙烯酸二甲基氨基乙酯(DMAEMA)接枝于硅胶微粒表面, 制得了功能接枝微粒PDMAEMA/SiO₂, 采用本课题组建立的新型分子表面印迹技术, 以天冬氨酸(Asp)的一种对映体L-Asp为模板分子, 二氯乙醚为交联剂, 对接枝在硅胶表面的大分子PDMAEMA实施了分子印迹, 制备了L-Asp分子表面印迹材料MIP-PDMAEMA/SiO₂. 以天冬氨酸的另一种对映体D-Asp为对比物, 采用静态与动态两种方法深入研究了MIP-PDMAEMA/SiO₂对L-Asp分子的识别性能, 重点探索了采用分子表面印迹材料对氨基酸对映体进行拆分的可行性. 实验结果表明, 印迹材料MIP-PDMAEMA/SiO₂对模板分子L-Asp具有良好的识别选择性与结合亲和性, 相对于D-Asp, 识别选择性系数为3.24, 显示出良好的拆分性能. 此外, 印迹材料MIP-PDMAEMA/SiO₂也具有良好的解吸性能, 以稀NaOH水溶液作为洗脱液, 13个床体积内解吸率即可达到99.73%.     

表面引发接枝聚合法制备抗蚜威分子表面印迹材料及其分子识别与结合特性研究

基于表面引发接枝聚合,设计与建立了一种新的分子表面印迹(MIP)方法.先使用偶联剂γ-氨丙基三甲氧基硅烷(AMPS)对微米级硅胶微粒进行表面改性,制得改性硅胶AMPS-SiO2;在酸性水溶液体系中,凭借强静电相互作用,阴离子单体对苯乙烯磺酸钠(PSSS)被结合在模板分子抗蚜威周围;改性硅胶AMPS-SiO2表面的氨基与溶液中的过硫酸盐构成氧化还原引发体系,在硅胶微粒表面产生自由基,引发结合在模板分子周围的SSS及交联剂甲基双丙烯酰胺(MBA)在硅胶微粒表面发生接枝交联聚合,从而实现了抗蚜威分子的表面印迹,制得了抗蚜威分子表面印迹材料MIP-PSSS/SiO2.以残杀威为对比物,采用静态与动态两种方法,考察研究了分子表面印迹材料MIP-PSSS/SiO2对抗蚜威的分子识别特性与结合性能.研究结果表明,印迹材料MIP-PSSS/SiO2对抗蚜威分子具有特异的识别选择性与优良的结合亲和性,相对于残杀威分子,MIP-PSSS/SiO2对抗蚜威分子的识别选择性系数为9.373,显示出高的分子识别选择性.     

异丙威表面分子印迹材料的制备及其识别特性研究

将γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(MPS)接枝到硅胶表面,然后以异丙威为模板分子,甲基丙烯酸(MAA)为单体,乙二醇二缩水甘油醚(EGDE)为交联剂,制备了异丙威表面分子印迹材料MIP-P MAA-MPS-SiO2。采用动态与静态两种方法研究了该印迹材料对异丙威的结合性能与分子识别特性。结果表明,MIP-P MAA-MPS-SiO2印迹材料对模板分子异丙威具有良好的特异性识别作用,相对于参比物速灭威和甲萘威,印迹材料对异丙威的选择性系数分别为6.73和8.95。经过Scatchard模型分析,计算得到两类结合位点的最大表观吸附量分别为230和117 mg/g,印迹聚合物的平衡离解常数K d分别为1428.6和476.2 mg/L。油菜样品的加标回收实验表明,此印迹材料可以对痕量异丙威进行富集分离测定,且可重复使用。     

酸性染料分子表面印迹材料的设计与制备及其分子识别特性研究

本文使用"接枝交联聚合与印迹过程同步进行"的分子表面印迹方法,以阳离子单体丙烯酰氧乙基三甲基氯化铵(DAC)为功能单体,以活性艳红X-3B(RBR)为模板分子,制备了酸性染料分子表面印迹材料,并考察了印迹材料的分子识别性能。在水溶液中,凭籍强静电相互作用与阳离子-π相互作用,阳离子单体DAC自动地结合在模板RBR分子周围,在氨基/过硫酸盐表面引发体系作用下,DAC及交联剂N,N'-亚甲基双丙烯酰胺(MBA)在硅胶微粒表面发生接枝交联聚合,制得了酸性染料分子表面印迹材料MIP-PDAC/SiO2。该分子表面印迹材料对RBR分子具有高度的识别选择性,相对于结构与RBR相似的活性黄X-RG和活性嫩黄X-6G两种酸性染料,MIP-PDAC/SiO2对RBR的识别选择性系数分别为8.1和8.9。     

新型表面分子印迹法制备苦参碱印迹材料及其分子识别特性

通过γ-(甲基丙烯酰氧)丙基三甲氧基硅烷的媒介, 将功能大分子聚甲基丙烯酸(PMAA)偶合接枝到硅胶微粒表面, 形成了接枝微粒PMAA/SiO₂, 采用本课题组建立的新型分子表面印迹技术, 以生物碱苦参碱(来源于苦豆子)为模板分子, 乙二醇二缩水甘油醚(EGDE)为交联剂, 对接枝在硅胶表面的PMAA大分子链进行了分子印迹, 制备了苦参碱表面分子印迹材料MIP-PMAA/SiO₂. 以另一种生物碱金雀花碱(亦来源于苦豆子)为对比物, 采用静态与动态两种方法研究了MIP-PMAA/SiO₂对苦参碱的结合性能与分子识别特性. 实验结果表明, 印迹材料MIP-PMAA/SiO₂对苦参碱具有特异的识别选择性与优良的结合亲和性, 相对于金雀花碱(与苦参碱共存于苦豆子植物中, 且结构彼此相似), 识别选择性系数为8.14. 此外, 印迹材料MIP-PMAA/SiO₂也具有良好的解吸性能, 以含氯化钠的乙酸水溶液作为洗脱液, 17个床体积内解吸率达到99.77%.     

咖啡因替代物(茶碱)分子表面印迹材料的制备及其分子识别特性研究

采用巯基-过氧化苯甲酰(BPO)氧化还原引发体系,先实现了甲基丙烯酸缩水甘油酯(GMA)在微米级硅胶微粒表面的引发接枝聚合,制得接枝微粒PGMA/SiO2.使接枝大分子PGMA的环氧基团与5-氨基水杨酸(ASA)发生开环反应,将水杨酸基团键合在接枝大分子侧链,制得功能接枝微粒SA-PGMA/SiO2,并对其化学结构与表面电性能进行了表征.考察研究了功能微粒SA-PGMA/SiO2与咖啡因替代物茶碱分子之间的相互作用力.研究表明,微粒SA-PGMA/SiO2与茶碱分子之间存在有强的次价键力(静电和氢键相互作用).在此基础上,采用本课题组建立的新型分子表面印迹技术,以咖啡因替代物茶碱为模板分子,乙二醇二缩水甘油醚(EGDE)为交联剂,对接枝在硅胶表面的功能大分子链SA-PGMA进行了交联印迹,制备了茶碱分子表面印迹材料MIP-SAP/SiO2,深入考察研究了其分子识别特性.实验结果表明,相对于两种对照物甘油茶碱和苦参碱,印迹材料MIP-SAP/SiO2对茶碱分子具有特异的识别选择性与优良的结合亲和性,相对于甘油茶碱,印迹材料对茶碱的识别选择性系数为7.72.     

硅胶表面抗蚜威分子印迹聚甲基丙烯酸的制备及识别特性

通过γ-(甲基丙烯酰氧)丙基三甲氧基硅烷的媒介作用,将功能大分子聚甲基丙烯酸(PMAA)逐步接枝到硅胶微粒表面,形成了表面接枝聚甲基丙烯酸的硅胶微粒(PMAA/SiO2);以抗蚜威为模板分子、乙二醇二缩水甘油醚(EGDE)为交联剂,通过氢键和静电作用,对接枝到硅胶表面的PMAA进行分子印迹,制备了抗蚜威分子表面印迹材料硅胶表面分子印迹聚甲基丙烯酸MIP-PMAA/SiO2;采用静态与动态两种方法研究了 MIP-PMAA/SiO2 对抗蚜威的结合特性,并考察了主要印迹条件 pH、混合溶剂中乙醇含量以及交联剂用量对印迹材料结合选择性能的影响.结果表明:表面印迹材料 MIP-PMAA/SiO2对抗蚜威具有特异的结合选择性,相对于参比物残杀威,印迹前 PMAA/SiO2对抗蚜威的吸附选择系数为 1.52,而表面印迹材料 MIP-PMAA/SiO2 对抗蚜威的吸附选择系数提高到 12.2.另外该印迹材料具有优良的洗脱与再生性能.     

胆红素分子表面印迹材料MIP-PMAA/SiO2的制备及识别特性

通过γ-（甲基丙烯酰氧）丙基三甲氧基硅烷的媒介作用,在硅胶微粒表面偶合接枝聚甲基丙烯酸（PMAA）,制备了PMAA/SiO2接枝微粒。采用新型分子表面印迹技术,以乙二醇二缩水甘油醚（EGDE）为交联剂,制备了以胆红素为模板分子的表面印迹材料MIP-PMAA/SiO2。分别通过静态和动态吸附实验考查了该印迹材料对胆红素的识别特性。结果表明：该印迹材料对胆红素兼具优良的结合亲和性和特异的识别选择性,同时,具有优良的脱附性能,脱附率可达99.5%。     

生物碱分子表面印迹聚合物材料的设计与制备及其分子识别特性

采用巯基/偶氮二异丁腈(AIBN)表面引发体系,实现了甲基丙烯酸缩水甘油酯(GMA)在微米级硅胶微粒表面的引发接枝聚合,制得接枝微粒PGMA/SiO2;然后使接枝大分子PGMA的环氧基团与间二氨基苯磺酸钠(SAS)分子中的对位氨基发生开环反应,将苯磺酸钠基团键合在接枝大分子侧链,制得苯磺酸盐功能化的接枝微粒SAS-PGMA/SiO2。 在对功能微粒SAS-PGMA/SiO2与苦参碱分子间的相互作用进行考察研究的基础上,以戊二醛为交联剂,实施了苦参碱分子的表面印迹,制备了苦参碱分子表面印迹材料MIP-SASP/SiO2。 实验结果表明,在近中性溶液中,功能接枝微粒SAS-PGMA/SiO2与苦参碱分子间存在静电相互作用,以此为基础所设计与制备的表面印迹材料MIP-SASP/SiO2对苦参碱分子具有特异的识别选择性与优良的结合亲和性。 相对于对照物金雀化碱而言,该印迹材料对苦参碱的识别选择性系数为10.7。     

导电聚苯胺电极柱识别天冬氨酸对映体的研究

以苯胺为单体,L-天冬氨酸(L-Asp)为模板分子,采用化学氧化法合成了掺杂L-Asp的导电聚苯胺(PAn).将PAn作为固定相填充到多孔陶瓷管中制备导电PAn电极柱,并以此电极柱作为工作电极.循环伏安图表明PAn电极柱具有良好的电化学活性.在电极柱上施加-0.6 V的还原电位,PAn中掺杂的L-Asp发生脱掺杂,从而在PAn膜上留下了与L-Asp完全匹配的空穴.由于PAn具有掺杂/脱掺杂完全可逆的独特性能,因此对带有分子印迹的PAn电极柱施加0.5 V的正电位后,由于存在强烈的分子印迹作用,L-Asp在电极柱上被富集,而D-天冬氨酸(D-Asp)的富集效果远低于L-Asp,从而实现对Asp对映体的识别.     

Constructing chiral caves and efficiently separating enantiomers of glutamic acid with novel surface-imprinting technique

Dimethylaminoethyl methacrylate (DMAEMA) was first graft-polymerized onto the surfaces of micron-sized silica gel particles in the manner of "grafting from" in a solution polymerization system, obtaining the grafted particles PDMAEMA/SiO(2). Then, the molecular imprinting towards the grafted PDMAEMA was conducted with one enantiomer of glutamic acid (Glu), L-Glu, as template molecule and with 2,2'-dichlorodiethylether (DCEE) as crosslinking agent by adopting the novel surface-molecular imprinting technique established by our research group, and the single enantiomer (L-Glu) molecule-imprinted material MIP-PDMAEMA/SiO(2) was obtained. With another enantiomer of glutamic acid, D-Glu, as the contrast compound, the recognition property of MIP-PDMAEMA/SiO(2) for L-Glu was investigated in depth with both static and dynamic methods, and its ability to separate L-Glu and D-Glu in the racemic solution was examined. The experiment results show that the surface-imprinted material MIP-PDMAEMA/SiO(2) has fine recognition selectivity and binding affinity for l-Glu, whereas its ability to combine D-Glu is poor. The selectivity coefficient of MIP-PDMAEMA/SiO(2) for L-Glu with respect to D-Glu is equal to 3.30, displaying an excellent chiral separation result. It is obvious that in this study, the substance separation at the molecular configuration level has been realized successfully.     

Method for on-line derivatization and separation of aspartic acid enantiomer in pharmaceuticals application by the coupling of flow injection with micellar electrokinetic chromatography

A novel, easy and accurate capillary electrophoresis (CE) coupled with flow injection (FI) method for the separation and determination of aspartic acid (Asp) enantiomers by on-line derivatization had been developed, and it had been applied to the real sample for the first time. The derivatization reagents were o-phthalaldehyde (OPA) and mercaptoethanol (ME), which were obtained easily, the chiral selector was beta-cyclodextrin (beta-CD), the micellar chemical was sodium dodecyl sulfate (SDS), and the modifier was methanol. By on-line derivatization, aspartic acid enantiomers were automatically and reproducibly converted to the ultraviolet (UV)-absorbing diastereoisomer derivates, which were separated by micellar electrokinetic chromatography (MEKC). According to the factors affecting the separation and sensitivity of aspartic acid enantiomer and other amino acids in the real sample, the pH value and concentration of the buffer, the concentration of beta-CD and SDS, the volume percentage of the methanol (v/v) in the buffer, the applied voltage and the conversion time were selected as the investigating variates. Under the investigated separation conditions, D-aspartic acid (D-Asp), L-aspartic acid (L-Asp) and other four amino acids achieved the baseline separation in not only the standard mixture of amino acids but also the real sample (Compound Amino Acid Injection (6AA)). The repeatability (defined as relative standard deviation (RSD), n = 5) was 4.0% and 4.0% with peak area evaluation, and 4.2% and 3.7% with peak height evaluation for D-Asp and L-Asp in the real sample. Recovery at added standard levels of 1.0, 3.0 and 6.0 mM was 92%, 104% and 109%, respectively.     

接枝微粒材料P4VP-SiO_2对酸性氨基酸的吸附性能与吸附机理

将4-乙烯基吡啶(4VP)接枝聚合于微米级硅胶表面,制得了接枝有聚4-乙烯基吡啶(P4VP)的接枝微粒P4VP-SiO_2,测定了P4VP-SiO_2的红外光谱,袁征了其化学结构,并测定了该复合型功能微粒材料的Zeta电位.采用静态法研究了P4VP-SiO_2对酸性氨基酸天冬氨酸与谷氨酸的吸附性能,考察了介质pH、离子强度及温度对其吸附性能的影响,探索了吸附机理.研究结果表明:在较大的pH范围内,P4VP-SiO_2的Zeta电位为较高的正值,即微粒表面携带有高密度的正电荷;酸性氨基酸天冬氨酸与谷氨酸等电点都较低,所以在一般的介质pH范围内,它们的分子带有负电荷;凭借静电相互作用,P4VP-SiO_2对酸性氨基酸天冬氨酸与谷氨酸均表现出很强的吸附能力,而对中性与碱性氨基酸(在一般的介质pH范围内分子带有正电荷)的吸附能力则很弱;随介质pH的增大,P4VP-SiO_2对天冬氨酸与谷氨酸的吸附能力呈现先增强后减弱的规律,在pH＝4处,吸附容量具有最大值,分别为280 mg/g与230 mg/g;温度升高,吸附容量减小;盐度增大,吸附容量降低.     

Continuous on-line derivatization and selective separation of D-aspartic acid by a capillary electrophoresis system with a continuous sample introduction interface

A rapid and selective method is described for the separation of D-aspartic acid (D-Asp) using a continuous on-line derivatization system coupled to capillary electrophoresis (CE). D-Asp was derivatized using o-phthaldialdehyde/N-acetyl-L-cysteine (OPA/NAC). By on-line derivatization, amino acid enantiomers were automatically and reproducibly converted to the UV-absorbing diastereomer derivatives which were separated by capillary zone electrophoresis (CZE) in the presence of 10 mmol/L beta-cyclodextrin (beta-CD). Under the investigated separation conditions, D-Asp is resolved from L-aspartic acid (L-Asp) and other amino acids in a standard mixture of amino acids. The separation could be achieved within 4 min and the sample throughput rate can reach up to 16 h(-1). The repeatability (defined as relative standard deviation, RSD) was 3.21%, 3.58% with peak area evaluation and 3.72%, 4.03% with peak height evaluation for L-Asp and D-Asp.     

基于离子交换和表面引发接枝聚合制备阴离子表面印迹材料及其识别特性研究

建立了一种新的离子表面印迹(IIP)方法. 使用偶联剂γ-氨丙基三甲氧基硅烷(AMPS)对微米级硅胶微粒进行表面改性, 制得表面含有氨基的改性硅胶AMPS-SiO₂. 凭借离子交换作用, 阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)结合在模板离子磷酸根周围; 改性硅胶AMPS-SiO₂表面的氨基与溶液中的过硫酸盐构成氧化还原引发体系, 使DMC及交联剂N,N'-亚甲基双丙烯酰胺(MBA)在硅胶微粒表面发生接枝交联聚合, 从而实现了磷酸根离子的表面印迹, 制得了阴离子表面印迹材料IIP-PDMC/SiO₂. 采用静态与动态两种方法, 考察研究了IIP-PDMC/SiO₂对PO₄^3-离子的识别特性与结合性能. 研究结果表明, 离子表面印迹材料IIP-PDMC/SiO₂对PO₄^3-离子具有特异的识别选择性与优良的结合亲和性, 相对于对比离子高锰酸根离子, IIP-PDMC/SiO₂对PO₄^3-离子的识别选择性系数为9.58.     

Preparation and phenol-recognizing ability of a poly(methacrylic acid) molecular imprint on the surface of a silica gel

Molecularly imprinted solid phase extraction is an excellent tool for the preconcentration of trace analytes. We report on the preparation of such a material by firstly graft-polymerizing methacrylic acid onto the surface of silica gel particles, and then imprinting it by using phenol as a template and ethylene glycol diglycidyl ether as a crosslinker. The binding and recognition of phenol were examined by static methods. The binding capacity at saturation is 160?mg·g^?1 in 9?h at pH 6. The selectivity coefficients relative to o-cresol and chlorophenol are 22 and 23, respectively. The pH value has a large effect. Adsorbed phenol can be eluted easily from the imprint with diluted sodium hydroxide solution, and the material is reusable.

Preparation and recognition performance of cytisine alkaloid‐imprinted material prepared using novel surface molecular imprinting technique

Methacrylic acid was first graft‐polymerized on the surfaces of micron‐sized silica gel particles in the manner of “grafting from” using 3‐methacryloxypropyl trimethoxysilane as an intermedia, obtaining the grafted particle polymethacrylic acid PMAA/SiO₂. By adopting the novel surface‐molecular imprinting technique put forward by us, cytisine molecule‐imprinted material MIP‐PMAA/SiO₂ was prepared with ethylene glycol diglycidyl ether as crosslinking agent. The binding characteristics of MIP‐PMAA/SiO₂ towards cytisine was investigated in depth with both batch and column methods and using matrine and oxymatrine as two contrast alkaloids, which with cytisine coexist in sophora alopecuroides and their chemical structure is similar to cytisine to a certain extent. The experimental results show that the surface‐imprinted material MIP‐PMAA/SiO₂ has excellent binding affinity for cytisine (20.1 g/100 g of binding capacity), and it is more important that MIP‐PMAA/SiO₂ has very high recognition selectivity for cytisine in relation to the two contrast alkaloids. The selectivity coefficients of the grafted particles PMAA/SiO₂ (non‐imprinted material) for cytosine in relation to matrine and oxymatrine are only 1.03 and 1.06, respectively, displaying no recognition selectivity for cytisine. However, after imprinting, the selectivity coefficient of MIP‐PMAA/SiO₂ for cytisine in respect to matrine and oxymatrine are remarkably enhanced to 12.08 and 15.05, respectively.     

表面引发接枝聚合法制备接枝微粒PHEMA/SiO2及其8-羟基喹啉功能化转变研究

通过用表面引发接枝聚合和高分子反应制备8-羟基喹啉型复合螯合微粒.首先使用γ-氨丙基三甲氧基硅烷(AMPS)对微米级硅胶微粒进行表面改性,制得改性微粒AMPS-SiO2;使改性微粒AMPS-SiO2表面的氨基与溶液中的过硫酸盐构成氧化-还原引发体系,实施了甲基丙烯酸羟乙酯(HEMA)在硅胶微粒表面的高效引发接枝聚合,制得了接枝微粒PHEMA/SiO2.又以5-氯甲基-8-羟基喹啉(CHQ)为试剂,使接枝的PHEMA发生大分子反应,实现了接枝微粒PHEMA/SiO2的8-羟基喹啉功能化转变,制得了复合微粒HQ-PHEMA/SiO2.采用多种手段对两种微粒进行了表征,重点研究了氨基-过硫酸盐表面引发接枝体系的接枝聚合机理,并研究了CHQ与接枝PHEMA的醇羟基之间取代反应的机理,还初步考察了功能微粒HQ-PHEMA/SiO2对重金属离子的螯合吸附性能.研究结果表明,氨基-过硫酸盐表面引发接枝聚合体系具有很高的引发活性,在室温(30℃)即可制得高接枝密度(40 g/100g)的接枝微粒PHEMA/SiO2;CHQ与接枝PHEMA的醇羟基之间的取代反应遵循SN1的反应历程,使用强极性溶剂有利于反应的进行.微粒HQ-PHEMA/SiO2对重金属离子呈现很强的螯合吸附能力,是一种功能复合微粒.