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1.
Feng Gao Xiaoxiao Chen Qingqing Ye Zhen Yao Xinyin Guo Lun Wang 《Mikrochimica acta》2011,172(3-4):327-333
pH-responsive fluorescent core-shell silica nanoparticles (SiNPs) were prepared by encapsulating the pH-sensitive fluorophore 8-hydroxypyrene-1,3, 6-trisulfonate into their silica shell via a facile reverse microemulsion method. The resulting SiNPs were characterized by SEM, TEM, fluorescence lifetime spectroscopy, photobleaching experiments, and photoluminescence. The core-shell structure endows the SiNPs with reduced photobleaching, excellent photostability, minimized solvatachromic shift, and increased fluorescence efficiency compared to the free fluorophore in aqueous solution. The dynamic range for sensing pH ranges from 5.5 to 9.0. The nanosensors show excellent stability, are highly reproducible, and enable rapid detection of pH. The results obtained with the SiNPs are in good agreement with data obtained with a glass electrode. Figure
Single-nanoparticle laboratories: core-shell silica fluorescent nanoparticles for pH sensing 相似文献
2.
Magnetic Fe3O4@SiO2 core shell nanoparticles containing diphenylcarbazide in the shell were utilized for solid phase extraction of Hg(II) from aqueous solutions. The Hg(II) loaded nanoparticles were then separated by applying an external magnetic field. Adsorbed Hg(II) was desorbed and its concentration determined with a rhodamine-based fluorescent probe. The calibration graph for Hg(II) is linear in the 60 nM to 7.0 μM concentration range, and the detection limit is at 23 nM. The method was applied, with satisfying results, to the determination of Hg(II) in industrial waste water. Figure
Functional magnetic Fe3O4@SiO2 core shell nanoparticles were utilized for solid phase extraction of Hg(II) from aqueous solutions, and the extracted Hg(II) was determined by a rhodamine-based fluorescent probe RP with satisfying results. 相似文献
3.
Gold electrodes were modified with self assembled layers (SAMs) composed of mercaptopropionic acid, thiodipropionic acid, dithiodipropionic acid, cysteamine and gold nanoparticles and used to study the electrooxidation of dopamine (DA) in solution at pH 7. SAMs endowed with gold nanoparticles gave the highest catalytic effect. The results showed that such electrodes are capable of resolving the oxidation peaks of DA, ascorbic acid, and uric acid which is most favourable with respect to the detection of DA in physiological matrices. Figure
Gold electrodes modified with S-containing compound and gold nanoparticles were used for determination of dopamine in aqueous solution. The modified electrodes could clearly resolve the oxidation peaks of dopamine, ascorbic acid and uric acid with peak-to-peak separation enabling determination of these compounds in the presence of each other. 相似文献
4.
We report on a novel method for visual detection silver(I) ion. It is based on the finding that Ag(I) ions are rapidly reduced by hydroquinone to form a shell of silver on the surface of gold nanoparticles (AuNPs) which act as catalysts for this reaction. This leads to a color change from red to yellow which can be seen with bare eyes. This scheme is sensitive and highly specific for Ag(I) ions. The detection limits are 5 μM for visual inspection and 1 μM for photometric readout, respectively. The method was successfully applied to the determination of Ag(I) ions in spiked lake water and soil.
A novel visual detection method based on the catalysis of gold nanoparticles was developed for the determination of Ag+ in the lake water and soil. 相似文献
5.
Magnetic nanoparticles with an imprinted polymer coating for the selective extraction of uranyl ions
We have synthesized ferromagnetic nanoparticles with an imprinted polymer coating that is capable of adsorbing and extracting uranyl ions. The adsorbent was characterized using infrared spectroscopy, elemental analysis, X-ray powder diffraction analysis, and scanning electron microscopy. The effects of sample pH, sample volume, weight of the adsorbent, contact time and of other ions have been investigated in the batch extraction mode. The performance of the material was compared to that of particles coated with a non-imprinted polymer. The adsorbent containing the imprinted coating displays higher sorption capacity and better selectivity to uranyl ions. The method was successfully applied to the determination of uranyl ions in water samples. Figure
Magnetic separation of uranyl ions from aqueous solution using a new uranyl-imprinted material prepared by surface modification of silica coated magnetic nanoparticles 相似文献
6.
Chunwei Yu Jun Zhang Jinhua Li Ping Liu Peihai Wei Lingxin Chen 《Mikrochimica acta》2011,174(3-4):247-255
A fluorescent probe for Cu(II) ion is presented. It is based on the rhodamine fluorophore and exhibits high selectivity and sensitivity for Cu(II) ion in aqueous methanol (2:8, v/v) at pH 7.0. The response is based on a ring opening reaction and formation of a strongly fluorescent 1:1 complex. The response is reversible and linear in the range between 50?nM and 900?nM, with a detection limit of 7.0?nM. The probe was successfully applied to fluorescent imaging of Cu(II) ions in HeLa cells. Figure
A novel fluorescent probe 1 based on a rhodamine spirolactame derivative exhibits highly selective and sensitive recognition properties toward Cu(II) in aqueous methanol (2:8, v/v) at pH 7.0 with remarkable fluorescence enhancement and clear color change, and its high cell permeability grants its application to fluorescent imaging in living cells. 相似文献
7.
Haijun Cui Ying Chen Lianshan Li Yishi Wu Zhiyong Tang Hongbing Fu Zhiyuan Tian 《Mikrochimica acta》2014,181(13-14):1529-1539
Conjugated polymer nanoparticles (CPNs) were developed based on a polyfluorene-based conjugated polymer with thiophene units carrying pyridyl moieties incorporated in the backbone of polymer chains (PFPyT). Hybrid CPNs fabricated from PFPyT and an amphiphilic polymer (NP1) displayed pH-sensitive fluorescence emission features in the range from pH 4.8 to 13, which makes them an attractive nanomaterial for wide range optical sensing of pH values. The fluorescence of hybrid CPNs based on chemically close polyfluorene derivatives without pyridyl moieties (NP3), in contrast, remains virtually unperturbed by pH values in the same range. The fluorescence emission features of NP1 underwent fully reversible changes upon alternating acidification/basification of aqueous dispersions of the CPNs and also displayed excellent repeatability. The observed pH sensing properties of NP1 are attributed to protonation/deprotonation of the nitrogen atoms of the pyridine moieties. This, in turn, leads to the redistribution of electron density of pyridine moieties and their participation in the π-conjugation within the polymer main chains. The optically transparent amphiphilic polymers also exerted significant influence on the pH sensing features of the CPNs, likely by acting as proton sponge and/or acid chaperone. Figure
pH-sensitive fluorescent nanoparticles were fabricated from pyridine-functionalized conjugated polymer; protonation/deprotonation of the nitrogen atoms of pyridine moieties upon pH changes, which leads to the redistribution of electron density of pyridine moieties and their participation in the π-conjugation with polymer chains, were confirmed. 相似文献
8.
Silver–polypyrrole (PPy) core–shell nanoparticles have been fabricated by a facile one-step “green” synthesis using silver nitrate as an oxidant and soluble starch as an environmentally benign stabilizer and co-reducing agent. The morphology and optical properties of the particles were significantly affected by the reaction temperature, soluble starch concentration, and ratio of pyrrole monomer to AgNO3 oxidant. The core–shell nanoparticles exhibited outstanding dispersive properties in deionized water due to residual starch, as compared with PPy nanoparticles in which starch was absent. The mechanism of core–shell nanoparticle formation was elucidated through TEM imaging vs. reaction time. The colloidal and chemical stability of the nanoparticles was demonstrated in a variety of solvents, including acids, bases, and ionic and organic solvents, through monitoring the localized surface plasmon resonance of the nanoparticles. Furthermore, the catalytic properties of these silver–PPy core–shell nanoparticles were also demonstrated. Figure
Schematic illustration of silver-PPy core-shell nanoparticle formation and methylene blue (MB) reduction using the core-shell nanoparticles as a catalyst. 相似文献
9.
Sebastian Rauch Petra Uhlmann Klaus-Jochen Eichhorn 《Analytical and bioanalytical chemistry》2013,405(28):9061-9069
The dynamic and reversible switching behaviour of polyelectrolyte brushes of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) toward changes of the pH value was studied by in situ VIS-spectroscopic ellipsometry (SE). For this, PDMAEMA brushes with three different molecular weights were synthesized via the “grafting from” method using surface initiated atom transfer radical polymerization. In detail, the applicability of different SE data modelling to describe the optical properties of the different brush layers in the swollen and collapsed state was investigated. Especially for the PDMAEMA brushes with a high molecular weight, an improved optical modelling of the experimental data could be achieved and revealed an exponential distribution of the PDMAEMA fraction in the brush layer. Figure
Analysis of the volume fraction-depth profile of pH responsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes attached to a gold substrate using VIS-spectroscopic ellipsometry. 相似文献
10.
Determination of acetamiprid by a colorimetric method based on the aggregation of gold nanoparticles
A method was developed for the detection of the insecticide acetamiprid based on the strong interaction of the cyano group of acetamiprid with gold nanoparticles (AuNPs). The interaction results in the aggregation of gold nanoparticles and is accompanied by a color change from red to purple. The concentration of acetamiprid can be determined qualitatively and quantitatively by visually monitoring the color change or by using a spectrometer. Transmittance electron microscopy and UV-vis spectroscopy have been used to characterize the process. The experimental parameters were optimized with regard to the size of the AuNPs, pH, and incubation time. Under optimal experimental conditions, linear relationships between the logarithm of the concentration of acetamiprid and the absorbance were found over the range of 0.66 to 6.6???M for AuNPs with diameters of 22.0?±?1.0?nm and of 6.6?C66???M for AuNPs with diameters of 15.0?±?1.0?nm. This method was successfully applied to detect acetamiprid in vegetables. Figure
A method was developed for the detection of acetamiprid based on the strong interaction of the cyano group of acetamiprid with gold nanoparticles. This method is rapid, sensitive and low-cost. It can be used for pesticide residues detection. 相似文献
11.
Poly(ethyleneimine) (PEI) dendrimers up to the third generation (G3) were prepared by a divergent synthesis method from an ethylenediamine (EDA) core. The amine terminals were bonded with vinylbromide by a Michael addition reaction. Then, the bromide terminals were converted to amine groups using a Gabriel amine synthesis method. PEI dendrimers displayed pH-dependent luminescence, and their emission intensities at pH 6 increased over time. Fluorescence intensities also increased with increasing dendrimer generation from G1 to G3. Air-bubbling in aqueous solutions of dendrimers made to incorporate detectable amount of oxygen in dendrimers. EDA also behaved similarly in luminescence and oxygen incorporation. Figure
Synthesis and Characterization of Poly(ethyleneimine) Dendrimers 相似文献
12.
We describe a simple and rapid method for colorimetric and bare-eye detection of the alkaline earth metal ions Mg(II), Ca(II), Sr(II) and Ba(II) based on the use of silver nanoparticles (AgNPs) functionalized with thioglycolic acid (TGA). The TGA ligand was self-assembled onto the AgNPs to form a probe that undergoes a color change from yellow to orange or red on exposure to the alkaline earth ions. It is presumed that the color change is a result of the aggregation of the AgNPs caused by the interaction of the bivalent ions with the carboxy groups on the AgNPs. The color change can be used for bare-eye and colorimetric determination of the alkaline earth metal ions, for example to rapidly determine water hardness. Figure
We have developed an efficient colorimetric method for alkaline earth metal ions using silver nanoparticles functionalized with thioglycolic acid as probe. This probe selectively recognizes alkaline earth metal ions through a distinct visual color change from yellow to red. 相似文献
13.
Liansheng Duan Lijun Yang Huayu Xiong Xiuhua Zhang Shengfu Wang 《Mikrochimica acta》2013,180(5-6):355-361
We report on a glassy carbon electrode modified with carbon-coated nickel nanoparticles (C-Ni/GCE) that can be used to study the electrochemical properties of rutin and its interaction with bovine serum albumin (BSA) via cyclic voltammetry and differential pulse voltammetry. The effects of pH value, accumulation potential, accumulation time and reaction time were optimized. A pair of reversible peaks is found in the potential range of 0 to around 0.6 V at pH?5.0. Two linear response ranges (with different slopes) are found, one in the 2 to 210 nM concentration range, the other between 0.21 and 1.72 μM. The detection limit is as low as 0.6 nM. On addition of BSA to the rutin solution, a decrease of the current is observed that is proportional to the concentration of BSA. The binding constant and stoichiometric ratio were calculated. Figure
1. Preparation of carbon-coated nickel nanoparticles modified glassy carbon electrode (C-Ni/GCE). 2. C-Ni/GCE improves the electrochemical redox of rutin. 3. The prepared electrode determines rutin with high sensitivity and selectivity. 4. The developed method can determine rutin and its interaction with bovine serum albumin. 相似文献
14.
Min Liu Zhuyuan Wang Shenfei Zong Ruohu Zhang Dan Zhu Shuhong Xu Chunlei Wang Yiping Cui 《Analytical and bioanalytical chemistry》2013,405(18):6131-6136
Oligonucleotide-modified nanoparticle conjugates show highly promising potential for SERS-based DNA detection. However, it remains challenging to carry out the SERS-based DNA detection in aqueous solutions directly using oligonucleotide-modified nanoparticles, because the Raman reporters would exhibit lower signals when they are dispersed in aqueous solutions than laid on “dry” metal nanoparticles. Here, we synthesized stable oligonucleotide-modified Ag nanoprism conjugates, and performed SERS-based DNA detection in aqueous solution directly by using such conjugates in combination with Raman reporter-labeled, oligonucleotide-modified gold nanoparticles. The experimental results indicate that this SERS-based DNA detection approach exhibited a good linear correlation between SERS signal intensity and the logarithm of target DNA concentration ranging from 10?11~10?8 M. This sensitivity is comparable to those SERS-based DNA detection approaches with the “dry” process. Additionally, a similar correlation could also be observed in duplex target DNA detection by SERS hybrid probes. Our results suggest that the oligonucleotide-modified Ag nanoprisms may be developed as a powerful SERS-based DNA detection tool.
Scheme of SERS-based DNA detection in aqueous solutions. Capture DNA-modified Ag nanoprisms and Raman reporter-labeled, report DNA-modified gold nanoparticles are utilized in the detection 相似文献
15.
Abbas Afkhami Tayyebeh Madrakian Reza Ahmadi Hasan Bagheri Masoumeh Tabatabaee 《Mikrochimica acta》2011,175(1-2):69-77
We have developed a solid phase extraction method for the determination of cadmium ions in aqueous samples. It is based on the adsorption of Cd(II) on alumina nanoparticles coated with sodium dodecyl sulfate and modified with a newly synthesized Schiff base. Analytical parameters such as pH value, amount of adsorbent, type and concentration of eluent, flow rates of the sample and eluent, sample volume and matrix effects were optimized. Desorption is accomplished with 2?mol?L?1 nitric acid. Cd(II) was then determined by flame atomic absorption spectrometry. The maximum enrichment factor is 75. Under the optimum experimental conditions, the detection limit is 0.14???g?L?1 in original solution. The adsorption capacity of the modified sorbent is 4.90?mg?g?1 for cadmium ions. The method was applied to the determination of trace quantities of Cd(II) in water, wastewater, and biological and food samples with satisfactory results. Figure
Schematic representation of the loading L on the alumina nanoparticles 相似文献
16.
We have modified gold nanoparticles (AuNPs) with triazole acetamide to obtain a material for the sensitive and selective colorimetric determination of iodide. The functionalized AuNPs were prepared by a reductive single chemical step using a Cu(I)-catalyzed click reaction. The presence of iodide ions induces the aggregation of these AuNPs and results in a color change from wine-red to purple. The iodide-induced aggregation can be detected visually with bare eyes, but also by photometry. The detection limit is as low as 15 nM. The method displays excellent selectivity for iodide over other anions due to the selective interaction with the amido groups of the triazole. The method was applied to the determination of iodide in spiked lake waters. Figure
New triazole acetamide functionalized gold nanoparticles (ATTP-AuNPs) for sensitive and selective colorimetric detection of I? were developed. ATTP-AuNPs showed excellent selectivity toward I? due to the interaction between the amide groups of ATTP and I?. 相似文献
17.
Keying Zhang Na Zhang Li Zhang Jigui Xu Hongyan Wang Cong Wang Tao Geng 《Mikrochimica acta》2011,173(1-2):135-141
A sensitive amperometric sensor for hydrogen peroxide (HP) was constructed that is based on a glassy carbon electrode (GCE) modified with silver nanoparticles on poly(alizarin yellow R). The polymer was electropolymerized onto the surface of the GCE by cyclic voltammetry (CV), and the AgNPs were then electrodeposited onto its surface. The electrode was characterized by scanning electron microscopy and CV, and used for amperometric determination of HP. The electrode exhibits a favorable catalytic activity towards the reduction of HP, with a linear response range from 1.0???M to 450???M and a detection limit of 0.32???M. The sensor also displays high selectivity, excellent reproducibility, and good long-term stability. Figure
Schematic representation of the preparation process of the HP sensor and catalytic activity towards HP 相似文献
18.
Forugh Gudarzy Abdolmajid Bayandori Moghaddam Shahla Mozaffari Yadolah Ganjkhanlou Mahmood Kazemzad Reza Zahed Farhad Bani 《Mikrochimica acta》2013,180(13-14):1257-1262
We report on a novel luminescent method for the detection of folic acid (FA), a member of the vitamin B family. Y2O3 nanoparticles were doped with europium(III) ions and surface-modified with captopril. Their fluorescence is quenched by FA, and intensity is a function of folic acid concentration in the 0.1 – 40 μM concentration range. The detection limit is 83 nM of FA at pH 7 and room temperature. Figure
In this work, we propose a novel method based on the changes in the fluorescence intensity of nanoparticles. Modified Eu-doped Y2O3 nanoparticles by captopril have been used as a probe for the detection of folic acid. 相似文献
19.
The assay for alpha-fetoprotein (AFP) is based on the use of immobilized anti-AFP labeled with silver nanoparticles (AgNPs). The immunoreaction between the labeled antibody against AFP and free AFP takes place in pH 6.0 solution and leads to the formation of the respective immunocomplex which displays enhanced resonance light scattering (RLS) intensity at 480 nm. Under the optimal conditions, the intensity of the enhanced RLS is proportional to the concentration of AFP in the range from 0.10 to 50 ng mL?1, with a detection limit of 40 pg mL?1. The characteristics of RLS, the immunocomplex, the immuno response, and the optimum conditions of the immunoreaction have been investigated. The concentration of AFP in 20 serum specimens was determined by the new assay, and results are consistent with those obtained with a commercially available ELISA kit. Figure
A new resonance light scattering assay of AFP based on silver nanoparticle and immunoreaction was developed. 相似文献
20.
Siti Nur Akmar Mohd Yazid Suk Fun Chin Suh Cem Pang Sing Muk Ng 《Mikrochimica acta》2013,180(1-2):137-143
We report that fluorescent carbon nanodots (C-dots) can act as an optical probe for quantifying Sn(II) ions in aqueous solution. C-dots are synthesized by carbonization and surface oxidation of preformed sago starch nanoparticles. Their fluorescence is significantly quenched by Sn(II) ions, and the effect can be used to determine Sn(II) ions. The highest fluorescence intensity is obtained at a concentration of 1.75 mM of C-dots in aqueous solution. The probe is highly selective and hardly interfered by other ions. The quenching mechanism appears to be predominantly of the static (rather than dynamic) type. Under optimum conditions, there is a linear relationship between fluorescence intensity and Sn(II) ions concentration up to 4 mM, and with a detection limit of 0.36 μM. Figure
Highly fluorescent carbon nanodots (CDs) were synthesized from preformed starch nanoparticles via a green synthetic method. The potential application of these CDs as a sensing probe for Sn(II) ions were evaluated. Our studies showed that CDs are highly sensitive and selective towards Sn(II) detection in aqueous system. 相似文献