光子晶体传感器研究进展

光子晶体因其独特的光学性质,在传感器方面具有重要的应用价值.光子晶体构筑的传感器可以实现高灵敏的荧光检测和色度检测.本文综述了光子晶体传感器在荧光检测和色度检测中的相关工作,阐述其工作原理,并总结了光子晶体传感器的最新研究趋势.     

“食品中的铁元素检验”教学实验条件的优化*

2019年人教版普通高中化学必修一新增了“检验食品中的铁元素”实验,按照该实验方案检测菠菜中的铁元素,由于色素干扰不能观察到明显的实验现象。鉴于此,采用提取液显色后的色度透过率作为评价指标,以控制变量法为实验方法,对常见含铁食品、铁元素提取方法、提取时间、提取剂中盐酸浓度和提取剂用量等条件进行了研究和优化。优化后的实验结果表明:采用2 g豆筋、20 mL浓度为4 mol/L的盐酸、破壁机搅拌提取5 min后的提取液显色,其色度值为62%,显示很明显的血红色。此实验方案能够有效证明食品中铁元素的存在,具有明显的实验现象,能应用于教师演示实验和学生分组实验。     

麦尔多拉蓝作为电子介体的一次性血清酒精生物传感器

基于丝网印刷技术制备一次性碳电极,用Nafion固定麦尔多拉蓝(MS)作为电子介体,通过交联法用戊二醛将乙醇脱氢酶和氧化型辅酶Ⅰ固定于Nafion-MB修饰的电极上,制备一次性血酒精生物传感器。该传感器表现出良好的特异性、灵敏度和准确性。传感器响应电流与血清酒精浓度在2.0×10-4~2.5×10-3mol/L之间呈现良好的线性关系;检出限为1.3×10-4mol/L,达到95%稳态响应时间不超过20 s。探讨了pH、缓冲液、温度及干扰物质等对一次性血酒精生物传感器的影响。将传感器用于血清酒精实际样品的测定,取得了满意的结果。     

基于镍纳米团簇-铕混合物的纸基比率荧光传感器检测四环素——推荐一个研究型综合化学实验

介绍了一个科研转化的综合化学实验项目，基于镍纳米团簇(NiNCs)-铕混合物(NiNCs-Eu³⁺)荧光传感器检测四环素。实验包括NiNCs-Eu³⁺的制备、表征及对四环素的响应性能，纸基传感器的构建及可视化识别的分析方法探究。该实验综合性强、操作简便、成本低，有利于培养学生的实验技能和科研探究能力，让学生体验到一个“看得见”的综合化学实验。     

BODIPY基荧光探针的合成、表征及对铜离子的检测——推荐一个大学综合化学实验

介绍了一个大学综合化学实验——BODIPY基荧光探针的合成、表征及对铜离子的检测。该实验是一个科研转化的大学生综合化学实验,内容包括3,5-二氯BODIY的合成、BODIPY基荧光探针分子的合成,以及利用紫外-可见分光光度计和荧光光谱仪检测目标分子对金属离子的响应性。通过本实验,使学生了解BODIPY基荧光传感器这一科研前沿领域,激发学生对科学研究的兴趣,培养学生的科研探究能力。本实验综合了有机化学、仪器分析和应用波谱学知识点的学习,培养学生的实验操作技能,提升学生的综合及创新能力,建议纳入高年级综合化学实验课程。     

利用SPR生物传感器检测牛奶中的氨苄青霉素残留

近年来,在食品安全检测领域,利用表面等离子体共振(surface plasmon resonance,SPR)传感器结合免疫测定方法进行痕量物质检测的技术得到了迅速发展。本文采用表面等离子共振生物传感器检测牛奶中的氨苄青霉素残留。从pH值、离子浓度和配体浓度三个方面讨论了实验条件对配体在传感器表面固定的影响,实验结果表明pH值为4.5、离子浓度为10mM以及配体浓度为400μg.mL-1为较佳实验条件。在此实验条件下对BSA-氨苄青霉素偶联物进行了固定,并采用该传感器对不同浓度的氨苄青霉素的水溶液和牛奶溶液进行了检测,最低检测限LOD分别为1.7ng.mL-1和1.8ng.mL-1,均低于氨苄青霉素的最大残留检测限(maximum residue limit,MRL)4.1ng.mL-1,验证了检测方法的可行性。     

基于图像识别原理的金标试纸检测仪样机研制

采用一种互补金属氧化物半导体(简称CMOS)数字图像传感器(TSL1301),研制出了盐酸克伦特罗胶体金标试纸检测仪。在4种不同检测频率(5,30,50和70KHz)条件下,该检测仪线阵图像传感器TSL1301,对空白试纸条检测数据的变异系数均小于0.22%;盐酸克伦特罗浓度为1.0~4.0 ng/m L时,其加标液含量与试纸条T线显色度,具有良好的二次拟合特性(R~2=0.995)。该方法适用于现场对盐酸克伦特罗进行快速定量检测。     

双碳点比率荧光法检测果蔬残留多菌灵

利用双碳点荧光构建比率荧光传感器检测果蔬残留多菌灵。该方法线性范围为0.10～20μmol/L,检出限为2.9 nmol/L,回收率在92.2%～106.1%,相对标准偏差低于1.8%。选择性实验表明,方法在复杂食品基质中具有优异的抗干扰能力,可用于食品中残留多菌灵的灵敏检测。该方法的特异性主要由来自多菌灵和传感器的苯环引起的π-π堆积实现,并进一步通过电子转移方式造成传感器荧光猝灭。该研究为碳点荧光传感器在食品检测领域的应用提供了一种策略。     

韩国研发出小型传感器监测食品污染

韩国研究人员发明了一种小型生物芯片传感器,可快速、准确地对食品和环境污染进行检测。据韩联社报道,由郑奉铉领导的韩国生命科学和生物技术研究所研发的这种生物芯片传感器利用表面等离子体共振技术,即通过接收被扫描物体表面反射的激光共振信号来辨别分子层面的结构,从而检测被测对象的DNA和蛋白质是否受到污染。郑奉铉说,与那些只能用在实验室的笨重检测设备相比,这种可单手提起的新装置可进行“即时检验”,大大提高了检测效率。这种生物芯片传感器经过改造后,还可用于药品、供水系统的检测,甚至可以应用于军事领域。韩国研发出小型传感器监测食品污染     

银纳米簇传感器应用于醋酸浓度的检测研究

本文基于pH调控的变色酸2R稳定的银纳米簇构建一个pH荧光传感器,尝试将该传感器应用于检测弱酸溶液浓度。通过一列的条件探究实验得到最佳检测条件。在最佳检测环境中,成功的实现了对醋酸溶液浓度的检测。检测结果与标示量非常接近,相对误差小,误差值在允许范围之内。良好的实验结果证明该pH荧光传感器用于检测弱酸溶液的浓度具有可行性和实用性。     

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.     

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%).     

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.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.