Selective and sensitive SERS sensor for detection of Hg2+ in environmental water base on rhodamine-bonded and amino group functionalized SiO2-coated Au–Ag core–shell nanorods

RSC Advances ◽  
2015 ◽  
Vol 5 (41) ◽  
pp. 32168-32174 ◽  
Author(s):  
Pinyi Ma ◽  
Fanghui Liang ◽  
Quanping Diao ◽  
Di Wang ◽  
Qingqing Yang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Environmental Water ◽  
Core Shell ◽  
Amino Group ◽  
Trace Detection ◽  
Water Base

A novel SERS sensor for trace detection of Hg2+ using R6G-derive Schiff base bonded Au@Ag@SiO2–NH2 NRs was designed. The LOD is 0.33 pmol L−1.

Investigation of the effect of ring size on the product distribution for the Schiff base reaction of 2-acetylcycloalkanones with diamino alkanes

1995 ◽  
Vol 73 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Raul G. Enriquez ◽  
Juan M. Fernandez-G ◽  
Ismael Leon ◽  
William F. Reynolds ◽  
Ji.-Ping Yang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Condensation Reaction ◽  
2D Nmr ◽  
Product Distribution ◽  
Major Product ◽  
Ring Size ◽  
Amino Group ◽  
Amino Groups ◽  
Similar Product ◽  
Acetyl Group

The Schiff base condensation reaction of 1,2-diaminoethane with a series of 2-acetylcycloalkanones (from cyclopentanone to cyclooctanone) has been investigated and the products characterized by two-dimensional nuclear magnetic resonance. The site of attack of the amino groups, i.e., ring ketone or acetyl ketone, is determined primarily by ring size. 2-Acetylcyclohexanone yields two products in ca. 9:1 ratio, the major product where the two amino groups attack at the ring ketones of two different cyclohexanone molecules, and the minor product where one amino group attacks one ring carbonyl of one cyclohexanone while the second amino group attacks the acetyl group of another. 2-Acetylcyclopentanone yields all three possible products with the major product involving attack at the acetyl groups of two different cyclopentanones. The corresponding reactions for 2-acetylcycloheptanone and 2-acetylcyclooctanone each give a single product corresponding to attack at the acetyl groups of two different cycloalkanones. Similar product distributions are observed for the reactions of the different 2-acetylcycloalkanones with 1,4-diaminobutane. Keywords: Schiff base reactions, diketones, 2D NMR.

scholarly journals Breaking the Carboxyl Rule

2013 ◽  
Vol 288 (29) ◽  
pp. 21254-21265 ◽  
Author(s):  
Sergei P. Balashov ◽  
Lada E. Petrovskaya ◽  
Eleonora S. Imasheva ◽  
Evgeniy P. Lukashev ◽  
Andrei K. Dioumaev ◽  
...  
Keyword(s):  
Schiff Base ◽  
Water Molecule ◽  
Proton Pump ◽  
Rate Constants ◽  
Proton Donor ◽  
Carboxyl Group ◽  
Amino Group ◽  
Wild Type ◽  
Fast Phase ◽  
Proton Uptake

A lysine instead of the usual carboxyl group is in place of the internal proton donor to the retinal Schiff base in the light-driven proton pump of Exiguobacterium sibiricum (ESR). The involvement of this lysine in proton transfer is indicated by the finding that its substitution with alanine or other residues slows reprotonation of the Schiff base (decay of the M intermediate) by more than 2 orders of magnitude. In these mutants, the rate constant of the M decay linearly decreases with a decrease in proton concentration, as expected if reprotonation is limited by the uptake of a proton from the bulk. In wild type ESR, M decay is biphasic, and the rate constants are nearly pH-independent between pH 6 and 9. Proton uptake occurs after M formation but before M decay, which is especially evident in D2O and at high pH. Proton uptake is biphasic; the amplitude of the fast phase decreases with a pKa of 8.5 ± 0.3, which reflects the pKa of the donor during proton uptake. Similarly, the fraction of the faster component of M decay decreases and the slower one increases, with a pKa of 8.1 ± 0.2. The data therefore suggest that the reprotonation of the Schiff base in ESR is preceded by transient protonation of an initially unprotonated donor, which is probably the ϵ-amino group of Lys-96 or a water molecule in its vicinity, and it facilitates proton delivery from the bulk to the reaction center of the protein.

Microfluidic-based fluorescent electronic eye with CdTe/CdS core-shell quantum dots for trace detection of cadmium ions

2020 ◽  
Vol 1131 ◽  
pp. 126-135 ◽  
Author(s):  
Xinyi Wang ◽  
Liubing Kong ◽  
Ying Gan ◽  
Tao Liang ◽  
Shuqi Zhou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Core Shell ◽  
Trace Detection ◽  
Cadmium Ions ◽  
Electronic Eye

Determination of Organophosphorous Pesticides in Environmental Water Samples Using Surface-Engineered C18 Functionalized Silica-Coated Core-Shell Magnetic Nanoparticles–Based Extraction Coupled with GC-MS/MS Analysis

2017 ◽  
Vol 100 (3) ◽  
pp. 804-809 ◽  
Author(s):  
Neha Srivastava ◽  
Supriya Kumari ◽  
Kishore Nair ◽  
Samsul Alam ◽  
Syed K Raza
Keyword(s):  
Magnetic Nanoparticles ◽  
Water Samples ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Core Shell ◽  
Aqueous Sample ◽  
Functionalized Silica ◽  
Method Performance ◽  
Ms Analysis

Abstract The present paper depicts a novel method based on magneticSPE (MSPE) for the determination of organophosphorus pesticides (OPs) such as phorate, malathion, and chlorpyrifos in environmental water samples. In this study, C18 functionalized silica-coated core-shell iron oxide magnetic nanoparticles (MNPs) were used as a surface-engineered magnetic sorbent for theselective extraction of pesticides from aqueous samples, followed by GC-MS and GC–tandem MS analysis for confirmative determination of the analytes. Various important method parameters, including quantity of MNP adsorbent, volume of sample, effective time for extraction, nature of the desorbing solvent, and pH of the aqueous sample, were investigated and optimized to obtain maximum method performance. Under the optimized instrumental analysis conditions, good linearity (r2 value ≥0.994) was achieved at the concentration range of 0.5–500 μg/L. Recoveries were in therange of 79.2–96.3 and 80.4–97.5% in selective-ion monitoring and multiple reaction monitoring (MRM) modes, respectively, at the spiking concentrations of 1, 5, and 10 μg/L. MRM mode showed better sensitivity, selectivity, and low-level detection (0.5 μg/L) of analytes. The novel MSPE method is a simple, cheap, rapid, and eco-friendly method for the determination of OPs in environmental water samples.

New Methods for the Fabrication of Composites for Supercapacitor Electrodes with High Active Mass Loading

MRS Advances ◽  
2018 ◽  
Vol 3 (54) ◽  
pp. 3221-3226 ◽  
Author(s):  
Aseeb M. Syed ◽  
Igor Zhitomirsky
Keyword(s):  
Schiff Base ◽  
Aldehyde Group ◽  
Amino Group ◽  
Mass Loading ◽  
Multiwalled Carbon ◽  
Active Mass ◽  
New Methods ◽  
Scan Rate ◽  
Schiff Base Formation ◽  
Base Formation

ABSTRACTMnO2-multiwalled carbon nanotube (MWCNT) supercapacitor electrodes with active mass loading of 30-45 mg cm-2 were prepared. In method 1, MnO2 and MWCNT were dispersed using 3,4-dihydroxybenzaldehyde (DHB) and toluidine blue (TD), respectively. The Schiff base formation between amino group of TD and aldehyde group of DHB facilitated improved mixing of MnO2 and MWCNT. In method 2, gallocyanine (GC) was used as a co-dispersant for MnO2 and MWCNT. The catecholate type bonding of DHB and GC allowed for adsorption of the dispersant molecules on MnO2 nanoparticles. The electrodes, prepared by method 1 showed higher capacitance, compared to the electrode, prepared by method 2. The highest capacitance of 7.8 F cm-2 (173 F g-1, 139 F cm-3) was obtained at a scan rate of 2 mV s-1 and active mass loading of 45 mg cm-2.

Core-Shell Structured Fe3O4/PPy Microspheres with High Magnetization for Purification of Plasmid DNA

2013 ◽  
Vol 716 ◽  
pp. 314-319 ◽  
Author(s):  
Hai Hui Jiang ◽  
Yan Zhou ◽  
Xiao Yun Han ◽  
Xin Cheng Chen ◽  
Yun Hua Hou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drug Delivery ◽  
Plasmid Dna ◽  
Magnetic Particles ◽  
Interfacial Polymerization ◽  
Core Shell ◽  
Magnetic Composite ◽  
Amino Group ◽  
High Quality ◽  
E Coli

Amino group-functionalized magnetic particles have wide applications in enzyme immobilization, DNA extraction, drug delivery, water purification, catalysis, and sensor. In this paper, Fe3O4/PPy microspheres with a well-defined coreshell structure have been prepared through an interfacial polymerization approach without surfactant. The magnetic composite spheres were characterized with XRD, FTIR, SEM, TEM, and magnetometry techniques, and further tested as the adsorbent to isolate plasmid DNA from Escherichia coli (E. coli) DH5α cells. The magnetic separation yields high-quality plasmid DNA in satisfying productivity as compared to the conventional phenolchloroform extraction.

scholarly journals A sensitive optical sensor based on DNA-labelled $$\hbox {Si}@\hbox {SiO}_{2}$$ Si @ SiO 2 core–shell nanoparticle for the detection of $$\hbox {Hg}^{2+}$$ Hg 2 + ions in environmental water samples

2017 ◽  
Vol 40 (7) ◽  
pp. 1455-1462 ◽  
Author(s):  
Krishnan Srinivasan ◽  
Kathavarayan Subramanian ◽  
Aruliah Rajasekar ◽  
Kadarkarai Murugan ◽  
Giovanni Benelli ◽  
...  
Keyword(s):  
Optical Sensor ◽  
Water Samples ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Core Shell
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