单分散Au纳米粒子液相合成与快速检测三聚氰胺——本科生综合化学实验

利用Au纳米粒子与三聚氰胺相互作用产生的颜色变化来快速评估牛奶中三聚氰胺的含量,采用透射电子显微镜表征Au纳米粒子与三聚氰胺作用前后的形貌变化,通过用紫外-可见吸收光谱数据绘制标准工作曲线来定量测定牛奶中三聚氰胺的含量。该实验贴近生活,学以致用,同时也有助于学生掌握无机化学和分析化学基本操作,对增强学生分析解决问题的能力,提升学生的科研素养也有帮助。     

出口乙醇中杂醇油测定方法的探讨

对国家标准规定的测定乙醇中杂醇油的气相色谱法和对二甲氨基苯甲醛比色法与水杨醛比色法进行了比较试验,试验结果表明,水杨醛比色法灵敏度最高,建议降低国标法的检出限以保证我国乙醇顺利出口。     

A Simple Simultaneous Colorimetric Determination of Primary and Secondary Amines with Fluorescamine

Abstract

Primary and secondary amines react reproducibly with fluorescamine to form pyrrolinones or aminoenone type chromophores with long wavelength absorption maxima in the 375–410 and 310–320 nm regions, respectively. A simple procedure has been worked out for the simultaneous colorimetric determination of primary and secondary amines.     

Spectrophotometric Determination of Methandienone in Tablets Using 1.4-Dihydrazinophthalazine

Abstract

A simple and sensitive method for the determination of methandienone in tablets using 1.4-dihydrazinophthalazine as the reagent is presented. The yellow coloured dihydralazinhydrazone shows the maximum at 401 nm and ntclar absorptivity of 1.5×10⁴ 1 mol^?1 cm^?1. Beer's law is obeyed up to 16 μ/mI methandienone. The method applied for the assay of methandienone in dosage form gave precise and reproducible results; recovery was 98.5% and relative standard deviation was 1. 5%.     

Colorimetric Sensing by Using Allosteric‐DNAzyme‐Coupled Rolling Circle Amplification and a Peptide Nucleic Acid–Organic Dye Probe

Target detection by the naked eye : The action of an RNA‐cleaving allosteric DNAzyme in response to ligand binding was coupled to a rolling circle amplification process to generate long single‐stranded DNA molecules for colorimetric sensing (see scheme). Upon hybridization of the resulting DNA with a complementary PNA sequence in the presence of a duplex‐binding dye, the color of the dye changed from blue to purple.

     

β-环糊精修饰的银量子点合成及其对色氨酸的比色手性识别

通过简便的一锅法合成了水溶性β-环糊精修饰的银量子点,成功实现了对D-和L-色氨酸比色区分识别．该银量子点对L-色氨酸可视化检测限为10^-4mol／L．     

宽锥角光束对分色合色膜色再现性能的影响

考虑了在CIEL*α*b*3D色空间中以色立体作为综合评价分色合色膜色再现性能的标准，分析了宽锥角光束入射时分色合色膜空间角度特性对图像色再现质量的影响，从优化色立体体积出发提出了用预补偿的方法来优化膜系设计，提高了宽锥角光束入射下膜系的色再现性能。     

Filling Carbon Nanotubes with Prussian Blue Nanoparticles of High Peroxidase‐Like Catalytic Activity for Colorimetric Chemo‐ and Biosensing

Facile filling of multiwalled carbon nanotubes (MWCNTs) with Prussian blue nanoparticles (PBNPs) of high peroxidase‐like catalytic activity was performed to develop novel colorimetric sensing protocols for assaying H₂O₂ and glucose. Fine control of PBNP growth was achieved by modulating the concentration ratio of K₃[Fe(CN)₆] and FeSO₄ precursors in an acidic solution containing ultrasonically dispersed MWCNTs, and thus size‐matched PBNPs could be robustly immobilized in the cavities of the MWCNTs (MWCNT‐PB_in). Unlike other reported methods involving complicated procedures and rigorous preparation/separation conditions, this mild one‐pot filling method has advantages of easy isolation of final products by centrifugation, good retention of the pristine outer surface of the MWCNT shell, and satisfactory filling yield of (24±2) %. In particular, encapsulation of PBNPs of poor dispersibility and limited functionality in dispersible and multifunctional MWCNT shells creates new and valuable opportunities for quasihomogeneous‐phase applications of PB in liquid solutions. The MWCNT‐PB_in nanocomposites were exploited as a peroxidase mimic for the colorimetric assay of H₂O₂ in solution by using 3,3′,5,5′‐tetramethylbenzidine (TMB) as reporter, and they gave a linear absorbance response from 1 μM to 1.5 mM with a limit of detection (LOD) of 100 nM . Moreover, glucose oxidase (GOx) was anchored on the outer surface of MWCNT‐PB_in to form GOx/MWCNT‐PB_in bionanocomposites. The cooperation of outer‐surface biocatalysis with peroxidase‐like catalysis of interior PB resulted in a novel cooperative colorimetric biosensing mode for glucose assay. The use of GOx/MWCNT‐PB_in for colorimetric biosensing of glucose gave a linear absorbance response from 1 μM to 1.0 mM and an LOD of 200 nM . The presented protocols may be extended to other multifunctional nanocomposite systems for broad applications in catalysis and biotechnology.