共查询到20条相似文献,搜索用时 10 毫秒
1.
Climent E Giménez C Marcos MD Martínez-Máñez R Sancenón F Soto J 《Chemical communications (Cambridge, England)》2011,47(24):6873-6875
A new chromo-fluorogenic sensing protocol for anionic surfactants in aqueous environments using silica functionalised nanoparticles containing imidazolium and thiol groups has been developed. 相似文献
2.
3.
A highly sensitive and selective two-photon sensing scheme for detection of cartap was developed by using Au@Ag bimetallic core-shell nanoparticles. Cartap was found to induce the aggregation of Au@Ag nanoparticles and up to 700-fold enhancement in two-photon photoluminescence. Huge enhancement in two-photon photoluminescence allows achieving a detection limit of as low as 0.0062 mg/kg, which is better than the conventional colorimetric methods. This two-photon sensing scheme has a broad dynamic range and displays excellent selectivity in detection of cartap against over other ten kinds of commonly used insecticides. 相似文献
4.
Nanoporous gold (NPG) with uniform pore sizes and ligaments was prepared by using a simple dealloying method. NPG electrodes exhibit excellent electrocatalytic activity towards the oxidation of CySH and the mechanism for the electrochemical reaction of CySH on NPG has been discussed. Interestingly, if the operating potential is fixed at 0.65 V, a strong current is observed and interferences by tryptophan and tyrosine are avoided. The calibration plot is linear in the concentration range from 1 μM to 400 μM (R2?=?0.994), and the quantification limit is as low as 50 nM. The NPG-modified electrode has good reproducibility, high sensitivity and selectivity, can be used to sense CySH in aqueous solution. Figure
Nanoporous gold with uniform pore sizes and ligaments was employed as sensitive and selective electrochemical sensor for detection of Lcysteine, and the quantification limit is as low as 50 nM. 相似文献
5.
Highly selective and sensitive visualizable detection of Hg2+ based on anti-aggregation of gold nanoparticles 总被引:1,自引:0,他引:1
For the widely used gold nanoparticles (AuNPs)-based colorimetric probes, AuNPs generally change from dispersion to aggregation state accompanying with corresponding color turning from red to blue. Although colorimetric probes based on the anti-aggregation of AuNPs show exceptional selectivity and sensitivity, few examples have been reported in literature. A facile but highly sensitive and selective colorimetric probe based on the anti-aggregation of AuNPs transferred from the deactivation of aggregation agent 4,4′-dipyridyl by Hg2+ was developed in this work. This reported probe is suitable for real-time detection of Hg2+ in water with a detection limit of 3.0 ppb for Hg2+, and exhibits a selectivity toward Hg2+ by two orders of magnitude over other metal ions. The dynamic range of this probe can be conveniently tuned by adjusting the amount of 4,4′-dipyridyl used. 相似文献
6.
Aruna J. Weerasinghe 《Tetrahedron letters》2009,50(46):6407-3526
A new fluorescent sensor capable of sensing Cr3+ has been synthesized. Complexing with Cr3+ triggers the formation of a highly fluorescent ring-open form which is pink in color. The sensor shows extremely high fluorescence enhancement upon complexation with Cr3+ and it can be used as a ‘naked eye’ sensor. Binding of Cr3+ was found to be reversible as the pink color disappears with excess EDTA. 相似文献
7.
A novel electrochemical detection methodology is described for the femtomolar detection of proteins which utilizes both DNA aptamer-functionalized nanoparticles and a surface enzymatic reaction. Immunoglobulin E (IgE) was used as a model protein biomarker, which possesses two distinct epitopes for antibody (anti-IgE) and DNA aptamer binding. A surface sandwich assay format was utilized involving the specific adsorption of IgE onto a gold electrode surface that was pre-modified with a monolayer of aptamer-nanoparticle conjugates followed by the specific interaction of alkaline phosphatase (ALP) conjugated anti-IgE. To clearly demonstrate the signal enhancement associated with nanoparticle use, anodic current measurements of the ALP catalyzed oxidation of the enzyme substrate 4-aminophenylphosphate (APP) were also compared with electrode surfaces upon which the aptamer was directly attached. The detection of an unlabelled protein at concentrations as low as 5 fM is a significant improvement compared to conventional electrochemical-based immunoassay approaches and provides a foundation for the practical use and incorporation of nanoparticle-enhanced detection into electrochemical biosensing technologies. 相似文献
8.
Zheng Yuchuan Wang ·Shu Li Ruifeng Pan Le Li Liangqing Qi Zhaopeng Li Changjiang 《Research on Chemical Intermediates》2021,47(6):2421-2431
Research on Chemical Intermediates - Water-soluble fluorescent carbon dots (C-dots) were prepared by a hydrothermal process using guanine as the sole carbon and nitrogen source. The as-prepared... 相似文献
9.
Highly sensitive and selective colorimetric visualization of streptomycin in raw milk using Au nanoparticles supramolecular assembly 总被引:1,自引:0,他引:1
Sun J Ge J Liu W Fan Z Zhang H Wang P 《Chemical communications (Cambridge, England)》2011,47(35):9888-9890
Electrostatic interaction between streptomycin and mercaptoacetic acid modified gold nanoparticles can be used for a facile and reliable probe for streptomycin with high sensitivity and selectivity. 相似文献
10.
DNA phosphorylation is a vital process in the repair, replication, and recombination of nucleic acids. Traditionally, it is
assayed by denaturing gel electrophoresis and autoradiography, which are tedious and not sensitive. We report on the development
of a sensitive, simple, and economical method for DNA phosphorylation detection and T4 polynucleotide kinase (T4 PNK) activity
assay based on marking DNA phosphorylation/biotinylation events by the attachment of fluorescent nanoparticles. Enzyme activity
of T4 PNK is measured down to a limit of 5 × 10−6 U/ml, which is 400 times lower than previous reports. We also studied DNA phosphorylation specificity with different DNA
substrates. Furthermore, T4 PNK inhibition by the inhibitor ADP and activation by the activator spermine are shown, demonstrating
the potential for high-throughput screening for inhibitors and activators. 相似文献
11.
García-Acosta B Comes M Bricks JL Kudinova MA Kurdyukov VV Tolmachev AI Descalzo AB Marcos MD Martínez-Máñez R Moreno A Sancenón F Soto J Villaescusa LA Rurack K Barat JM Escriche I Amorós P 《Chemical communications (Cambridge, England)》2006,(21):2239-2241
Pyrylium-containing mesoporous materials have been used for the chromo-fluorogenic sensing of biogenic amines in an aqueous environment. 相似文献
12.
Gold nanoparticle based nanostructured electrode has been developed for the amperometric detection of ultratrace amount of toxic Cr(VI). The nano-sized Au particles have been grown on a conducting substrate modified with sol-gel-derived thiol functionalized silicate network and used for the electroanalysis of Cr(VI). The nanostructured interface show well-defined voltammetric peak for the reduction of Cr(VI) at approximately 0.4 V. The voltammetric behavior of Cr(VI) strongly depends on the coverage of nanoparticle on the electrode surface. Constant potential amperometry has been used for the detection of Cr(VI) at well below the guideline value set by World Health Organization (WHO). This electrode is highly sensitive (30+/-0.2 nA/ppb) and the detection limit (S/N=9) was 0.1 ppb. Cr(III) and coexisting other metal ions and surface active agent present in water do not interfere with the amperometric measurement of Cr(VI). This nanostructured electrode is highly stable and it can be used for continuous measurement of Cr(VI) without using any pretreatment or activation procedures. The accuracy of the measurement has been validated by measuring the concentration of Cr(VI) in the certified reference material (CRM). 相似文献
13.
《化学研究》2016,(2)
采用柠檬酸钠还原法合成粒径约13nm的纳米金粒子.采用紫外-可见分光光度计、荧光分光光度计研究了纳米金粒子与多西环素/土霉素分子的相互作用;通过改变缓冲溶液、纳米金粒子用量、反应时间确定了比色法测定的最优反应条件.结果表明:在弱酸溶液中,多西环素/土霉素分子中的氨基官能团(-NH_2)得到电子成为带电基团(-NH_3~+)并通过静电引力与纳米金粒子结合,使得纳米金粒子发生聚集,导致纳米金吸收光谱发生红移和展宽,颜色由酒红色变成蓝色;在盐酸-柠檬酸钠的缓冲溶液中加入2mL纳米金,反应时间为10min的条件下测得多西环素和土霉素的线性范围分别为0.06~0.66mg·L~(-1)和0.59~8.85 mg·L~(-1),检出限(3σ)分别为0.008 6、0.083 8mg·L~(-1).该方法前处理简单、灵敏、可靠,有望应用于食品分析和临床分析等领域. 相似文献
14.
《中国化学快报》2021,32(9):2807-2811
As an important component of the atmosphere, ammonia (NH3) plays a very important role in maintaining the balance of environment. However, it is also one of the most toxic gases that can cause damage to the human respiratory system and mucous membranes even at low concentrations. As such, development of highly sensitive and selective NH3 sensors is of high significance for environmental monitoring and health maintenance. Herein, we have synthesized Au@Ag@AgCl core-shell nanoparticles (NPs) by oxidative etching and precipitating Au@Ag core-shell NPs using FeCl3 and further used them as optical probes for the colorimetric detection of NH3. The sensing mechanism is based on the fact that the etching of NH3 on AgCl and Ag shell leads to the variations of ingredients and core-to-shell ratio of the Au@Ag@AgCl NPs, thereby inducing noticeable spectral and color changes. By replacing the outmost layer of Ag with AgCl, not only is the stability of the sensor against oxygen significantly enhanced, but also is the sensitivity of the method improved. The method exhibits good linear relationship for the detection of NH3 from 0 to 5000 μmol/L with the limit of detection of 6.4 μmol/L. This method was successfully applied to the detection of simulated air polluted by NH3, indicating its practical applicability for environmental monitoring. This method shows great potential for on-site NH3 detection particularly in remote area, where a simple, fast, low-cost, and easy-to-handle method is highly desirable. 相似文献
15.
A fluorometric method for quantity analysis of biothiols was developed using a graphene oxide (GO)-based “molecular beacon”-like probe, which consisted of FITC labeled thymine (T)-rich single-stranded DNA (ssDNA), GO and Hg2+ ions. The labeled ssDNA containing T–T mismatches would self-hybridize to duplex in the presence of Hg2+, which can avoid its adsorption on GO and the fluorescence of this GO-based probe was recovered. The fluorescence of the probe quenched after the addition of biothiols such as glutathione (GSH) and cysteine (Cys) owing to thiol groups can selectively competitive ligation of Hg2+ ions with T–T mismatches. In the present work, the GO-based probe was used for the determination of GSH and Cys. Under the optimal conditions, a linear correlation was established between fluorescence intensity ratio I0/I and the concentration of GSH in the range of 2.0 × 10−9–5.0 × 10−7 mol L−1 with a detection limit of 1.0 × 10−9 mol L−1. The linear range for Cys is from 5.0 × 10−9 to 4.5 × 10−7 mol L−1 with a detection limit of 2.0 × 10−9 mol L−1. The proposed method was applied to the determination of GSH in human serum and cell extract samples with satisfactory results. 相似文献
16.
Dorfman A Kumar N Hahm JI 《Langmuir : the ACS journal of surfaces and colloids》2006,22(11):4890-4895
Fluorescence detection is currently one of the most widely used methods in the areas of basic biological research, biotechnology, cellular imaging, medical testing, and drug discovery. Using model protein and nucleic acid systems, we demonstrate that engineered nanoscale zinc oxide structures can significantly enhance the detection capability of biomolecular fluorescence. Without any chemical or biological amplification processes, nanoscale zinc oxide platforms enabled increased fluorescence detection of these biomolecules when compared to other commonly used substrates such as glass, quartz, polymer, and silicon. The use of zinc oxide nanorods as fluorescence enhancing substrates in our biomolecular detection permitted sub-picomolar and attomolar detection sensitivity of proteins and DNA, respectively, when using a conventional fluorescence microscope. This ultrasensitive detection was due to the presence of ZnO nanomaterials which contributed greatly to the increased signal-to-noise ratio of biomolecular fluorescence. We also demonstrate the easy integration potential of zinc oxide nanorods into periodically patterned nanoplatforms which, in turn, will promote the assembly and fabrication of these materials into multiplexed, high-throughput, optical sensor arrays. These zinc oxide nanoplatforms will be extremely beneficial in accomplishing highly sensitive and specific detection of biological samples involving nucleic acids, proteins and cells, particularly under detection environments involving extremely small sample volumes of ultratrace-level concentrations. 相似文献
17.
18.
Gee HC Lee CH Jeong YH Jang WD 《Chemical communications (Cambridge, England)》2011,47(43):11963-11965
A new type of fluorescent probe (1) with two triazole groups that are conjugated with a carbazole moiety was synthesized by a Cu(I)-catalyzed alkyne-azide click reaction for the selective and sensitive detection of cyanide via fluorescence enhancement by ligand exchange and metal ion removal. 相似文献
19.
Senapati T Senapati D Singh AK Fan Z Kanchanapally R Ray PC 《Chemical communications (Cambridge, England)》2011,47(37):10326-10328
Contamination of the environment with toxic Hg(II) is becoming a huge concern throughout the world now. Driven by the need, this communication reports for the first time a tryptophan protected popcorn shaped gold nanomaterials based SERS probe for rapid, easy and highly selective recognition of Hg(II) ions in the 5 ppb level from aqueous solution, with high sensitivity and selectivity over competing analytes. We demonstrate that our SERS assay is capable of measuring the amount of Hg(II) in alkaline battery. 相似文献