肉桂酸苄酯分子印迹膜电化学传感器的制备

以肉桂酸苄酯为模板,巯基苯胺为单体,采用电聚合的方法合成了肉桂酸苄酯分子印迹聚合物膜,并以此印迹膜构建电化学传感器,采用差分脉冲伏安(DPV)法对化妆品中肉桂酸苄酯进行检测,结果表明在1.0×10~(-11)~1.0×10~(-8) mol/L浓度范围内与峰电流线性良好,相关系数R~2=0.9915,检测限为2.9pmol/L,并且具有较高的选择性识别能力、良好的再生性和稳定性。该方法实现了洗发水样品中痕量肉桂酸苄酯的检测,为测定和监控化妆品中痕量过敏原提供了一条有效途径。     

量子点荧光印迹传感器的计算机模拟设计、制备及检测河水中4-硝基苯酚的应用

将量子点的荧光特性、表面分子印迹技术与计算机模拟技术相结合,分别以碲化镉、4-硝基苯酚、3-氨丙基三乙氧基硅烷和正硅酸四乙酯作为量子点、模板分子、功能单体和交联剂,制得具有荧光特性的分子印迹聚合物.对其结构、形貌、荧光性能和选择性进行了表征,结果表明,该聚合物对4-硝基苯酚具有良好的选择性和灵敏度,线性范围为1.0~80 nmol/m L,检出限为0.05 nmol/m L.将制备的量子点荧光印迹聚合物作为传感器,应用于河水中4-硝基苯酚的测定,加标回收率为98.6%~101.2%,相对标准偏差最高为1.37%.     

石墨烯修饰电极分子印迹电化学传感器的研制及其对多巴胺的测定

以石墨烯为电极增敏材料,多巴胺印迹聚合物为特异性识别材料,采用滴涂法组装石墨烯修饰电极的分子印迹电化学传感器。考察了pH值、石墨烯浓度、印迹聚合物浓度对传感器的影响,优化的实验条件为:pH 7.0,石墨烯浓度为0.5g/L,印迹聚合物浓度为20g/L。实验表明,该印迹传感器对多巴胺的响应电流远大于非印迹电极,同时该印迹传感器对多巴胺具有较好的选择性,检测范围为2.0×10-7～1.0×10-4mol/L,检出限(S/N=3)为6.8×10-8mol/L。该传感器用于盐酸多巴胺注射液的测定,其回收率为98%～105%。     

分子印迹荧光传感构建及应用

构建一个高灵敏、高选择性检测痕量分析物的传感器广受科研工作者关注。分子印迹技术由于具有高选择性识别、高容量吸附、快速结合、热稳定性以及低成本等优点,已广泛应用于传感构建领域。以分子印迹聚合物为识别单元,结合荧光传感技术所构建的分子印迹荧光传感器在环境污染物痕量检测方面成为研究重点。本文主要介绍分子印迹聚合物的制备方法,总结分子印迹荧光传感器的构建机理和分子印迹荧光传感器在金属离子、有机小分子以及生物大分子检测方面的应用。重点探讨分子印迹传感器在不同数量的荧光团下检测一种或多种目标分析物的方法,包括单一荧光团检测单一目标物、比率荧光检测单一目标物以及分子印迹荧光传感的多元检测。基于以上分析和总结,提出分子印迹荧光传感器的当前挑战和发展前景。     

上转换纳米粒子-分子印迹复合荧光探针检测黄芩苷

构建了一种近红外激发上转换纳米粒子-分子印迹（UCNPs@MIPs）复合荧光探针，并应用于尿液中黄芩苷的检测。以黄芩苷作为模板分子，采用溶胶凝胶技术将SiO2包覆的上转换纳米粒子封装到分子印迹聚合物中。当模板分子被去除后，该复合材料留下特异性结合位点，与黄芩苷之间可产生静电引力相互作用。黄芩苷可使上转换纳米粒子发生荧光猝灭实现对其选择性荧光分析。最优条件下，黄芩苷的浓度在0.1～50μmol/L范围线性良好，检出限为0.03μmol/L，尿液样品的加标回收率为94.0%～100.5%，相对标准偏差为1.3%～3.9%。该方法可实现对黄芩苷的选择性检测。     

分子印迹滤过型净化柱净化/分子荧光光谱法测定花生根中白藜芦醇

以白藜芦醇(RES)为模板分子,凹凸棒土(ATP)为载体,β-环糊精(β-CD)和甲基丙烯酸(MAA)为双功能单体,采用表面分子印迹技术制备了白藜芦醇分子印迹聚合物(MIPs)。将制得的分子印迹聚合物作为吸附剂填料,填充滤过型净化柱,用于富集净化花生根中的白藜芦醇,建立了分子印迹滤过型净化柱净化/分子荧光光谱测定花生根中白藜芦醇的新方法。在最优化条件下,分子印迹聚合物对RES具有良好的选择性,最大吸附容量可达12.78 mg/g,白藜芦醇在0.1~100μg/m L浓度范围内呈良好的线性关系(r=0.999 7),方法检出限为0.048μg/L,样品加标回收率为86.2%~102.1%,相对标准偏差(RSD)为3.5%~5.8%。该方法高效、快速、选择性好,可用于白藜芦醇的快速检测。     

分子印迹荧光传感器的研制及其对呋喃妥因的特异性识别

采用柠檬酸作为碳源合成了荧光碳量子点(CDs),经硅烷化试剂改性后,以呋喃妥因为模板分子,在其表面合成了分子印迹聚合物(MIP-CDs)。以傅立叶变换红外光谱仪(FTIR)和扫描电镜(SEM)对合成产物进行结构和形貌表征;通过一系列吸附实验研究了MIP-CDs对呋喃妥因的识别性能。实验结果表明:在最佳吸附条件下,MIP-CDs的荧光猝灭程度与呋喃妥因的浓度符合Stern-Volmer方程,呋喃妥因在0~10mg/L质量浓度范围内具有良好的线性关系(r2=0.991 4),方法检出限(S/N=3)为2μg/L。在水样和饲料样品中添加不同浓度的呋喃妥因,加标回收率为78.0%~95.2%,相对标准偏差(RSD)不大于6.4%,符合分析方法学要求。该方法简单、快速、选择性好,可直接用于水体和饲料中痕量呋喃妥因的监测。     

苯胺分子印迹光子晶体水凝胶传感器的研究

基于分子印迹与光子晶体技术,制备了一种高灵敏、特异性好的苯胺水凝胶光学传感器。以Stober法制作的SiO_2微球作为三维光子晶体模板,苯胺为印迹分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸甲酯为交联剂,2,2-偶氮二异丁腈为光引发剂,在紫外光下引发聚合,并在三氯甲烷(加入适量乙醇)中洗脱印迹分子,最终得到具有对苯胺分子有传感功能的分子印迹光子晶体水凝胶传感器。实验结果表明,该传感器对苯胺分子具有良好的识别能力,当苯胺的浓度从0增加到1×10~(-4)mol/L时,通过光谱仪检测出的吸收峰偏移了42 nm。此外,该传感器在苯胺的结构类似物甲基苯胺的缓冲液的响应位移明显较小,表明该传感器具有良好的选择性。     

抑制荧光动力学法测定环境中痕量对硝基苯胺

在硫酸介质中,痕量对硝基苯胺对溴酸钾氧化罗丹明6G使其荧光猝灭具有抑制作用,由此建立了动力学荧光法测定痕量对硝基苯胺的分析新方法。考察了温度、反应时间、各种试剂条件对抑制反应的影响。在最佳实验条件下,方法线性范围为12~160 ng/mL,检出限为10.08 ng/mL。该方法应用于环境水样、土壤、大气等实际样品测定,回收率为96.8%~104.7%。     

西马特罗分子印迹荧光检测试纸条的研制

将分子印迹技术良好的选择性与试纸条快速检测的特点相结合,研制了一种快速检测西马特罗的分子印迹试纸条。以西马特罗为模板分子,化学聚合法制备西马特罗分子印迹聚合物,将其附着在硝酸纤维素膜上。洗脱模板分子后,裁剪压制得到分子印迹试纸条。试纸条识别样品中西马特罗后,滴加荧光物质曙红Y,根据反应区内西马特罗与曙红Y反应后荧光猝灭程度对西马特罗进行分析。研究结果表明,在0.01~100μg/mL浓度范围内,荧光猝灭程度随着西马特罗浓度的增加而增大,最低检测浓度为0.01μg/mL。此试纸条制备简单,操作简便,可用于现场检测。将其用于猪肉和饲料样品中西马特罗的快速测定,结果令人满意。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.