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2012 Volume 23 Issue 2
2012, 23(2): 127-129
doi: 10.1016/j.cclet.2011.11.015
Abstract:
A facile approach for the first total synthesis of naturally occurring geranylated flavanoids sepicanin A has been obtained with total yield 16% starting from 2, 4, 6-trihydroxyacetophenone after four steps. The key step was the protic acids (HCl or p-TsOH)-catalyzed benzopyrone formation in a protic polar solvent by deprotection and cyclization of chalcone in one step.
A facile approach for the first total synthesis of naturally occurring geranylated flavanoids sepicanin A has been obtained with total yield 16% starting from 2, 4, 6-trihydroxyacetophenone after four steps. The key step was the protic acids (HCl or p-TsOH)-catalyzed benzopyrone formation in a protic polar solvent by deprotection and cyclization of chalcone in one step.
2012, 23(2): 130-132
doi: 10.1016/j.cclet.2011.09.017
Abstract:
A novel one-pot protocol for the synthesis of substituted 2-aminooxazoline from isonitriles and 2-aminoethanol was developed and the reactions involved imidoyl diiodide intermediates, which were generated by mixing isonitriles and iodine in CH2Cl2 at room temperature.
A novel one-pot protocol for the synthesis of substituted 2-aminooxazoline from isonitriles and 2-aminoethanol was developed and the reactions involved imidoyl diiodide intermediates, which were generated by mixing isonitriles and iodine in CH2Cl2 at room temperature.
2012, 23(2): 133-136
doi: 10.1016/j.cclet.2011.11.017
Abstract:
A short and efficient synthesis of (Z)-2-substituted-5-(4-((2-substitued-5-oxoimidazolidin-4-ylidene)methyl)benzamido)-benzoic acid derivatives (8a-g) as potential type of FabH inhibitors is described. Their structures were confirmed by MS, NOE and 1H NMR.
A short and efficient synthesis of (Z)-2-substituted-5-(4-((2-substitued-5-oxoimidazolidin-4-ylidene)methyl)benzamido)-benzoic acid derivatives (8a-g) as potential type of FabH inhibitors is described. Their structures were confirmed by MS, NOE and 1H NMR.
2012, 23(2): 137-140
doi: 10.1016/j.cclet.2011.11.009
Abstract:
This paper presents the amination reactions of electron deficient aryl chlorides promoted by Mg(OH)2 without transition metals. Only using stoichiometric amount of nano sized Mg(OH)2, good to moderate isolated yields could be achieved in N-methylpyrrolidone (NMP) after 24h at 150℃.
This paper presents the amination reactions of electron deficient aryl chlorides promoted by Mg(OH)2 without transition metals. Only using stoichiometric amount of nano sized Mg(OH)2, good to moderate isolated yields could be achieved in N-methylpyrrolidone (NMP) after 24h at 150℃.
2012, 23(2): 141-144
doi: 10.1016/j.cclet.2011.11.018
Abstract:
Two novel organic hole-transporting materials have been synthesized by combination of triphenylamines (TPA) via π-conjugated bonds using Wittig reaction. The structures were characterized by NMR, FT-IR and HRMS. The optical, electrochemical and thermal properties of the materials were studied in detail. The results show that these two compounds have blue emission, proper HOMO levels and high thermal stability. Furthermore, a quantum chemical calculation on electron distribution of the two compounds was performed, which suggests the current synthesized materials would be promising candidates for hole-transporting materials.
Two novel organic hole-transporting materials have been synthesized by combination of triphenylamines (TPA) via π-conjugated bonds using Wittig reaction. The structures were characterized by NMR, FT-IR and HRMS. The optical, electrochemical and thermal properties of the materials were studied in detail. The results show that these two compounds have blue emission, proper HOMO levels and high thermal stability. Furthermore, a quantum chemical calculation on electron distribution of the two compounds was performed, which suggests the current synthesized materials would be promising candidates for hole-transporting materials.
2012, 23(2): 145-148
doi: 10.1016/j.cclet.2011.10.015
Abstract:
Synergistic effect of FeVO4 with α-Fe2O3 was found in Fe-V-O catalyst, which was responsible for the high apparent formation rate (A.F.R.) of benzaldehyde in liquid phase oxidation of toluene by hydrogen peroxide. The synergistic effect might create VOx species as active sites; moreover, it improved the reducibility and the reactivity of Fe-V-O catalyst. In order to gain the high A.F.R. of benzaldehyde, the catalyst should have the moderate reducibility.
Synergistic effect of FeVO4 with α-Fe2O3 was found in Fe-V-O catalyst, which was responsible for the high apparent formation rate (A.F.R.) of benzaldehyde in liquid phase oxidation of toluene by hydrogen peroxide. The synergistic effect might create VOx species as active sites; moreover, it improved the reducibility and the reactivity of Fe-V-O catalyst. In order to gain the high A.F.R. of benzaldehyde, the catalyst should have the moderate reducibility.
2012, 23(2): 149-153
doi: 10.1016/j.cclet.2011.10.017
Abstract:
Designed and synthesized a new highly water soluble N,N'-bis(2-((5-((dimethylamino)methyl)furan-2-yl)methylthio)-ethyl)perylene-3,4,9,10-tetracarboxylic diimide from 2-((5-((dimethylamino)methyl)furan-2-yl)methylthio)ethanamine and perylene-3,4,9,10-tetracarboxylic dianhydride. The compound was characterized by 1H, 13C, 2D NMR, mass and IR techniques. The compound is highly fluorescent with good solubility in water and other polar solvents.
Designed and synthesized a new highly water soluble N,N'-bis(2-((5-((dimethylamino)methyl)furan-2-yl)methylthio)-ethyl)perylene-3,4,9,10-tetracarboxylic diimide from 2-((5-((dimethylamino)methyl)furan-2-yl)methylthio)ethanamine and perylene-3,4,9,10-tetracarboxylic dianhydride. The compound was characterized by 1H, 13C, 2D NMR, mass and IR techniques. The compound is highly fluorescent with good solubility in water and other polar solvents.
2012, 23(2): 154-156
doi: 10.1016/j.cclet.2011.10.020
Abstract:
A new synthetic method for phosphatidylethanolamine head group was developed via ring-opening of cyclic dioxaphospholane 2 with sodium azide and subsequent hydrogenation. The advantage of this strategy included short reaction steps, readily available materials and good yields.
A new synthetic method for phosphatidylethanolamine head group was developed via ring-opening of cyclic dioxaphospholane 2 with sodium azide and subsequent hydrogenation. The advantage of this strategy included short reaction steps, readily available materials and good yields.
2012, 23(2): 157-160
doi: 10.1016/j.cclet.2011.11.011
Abstract:
A novel disulphide derivatised deuteroporphyrin 2, 7, 12, 18-tetramethyl-13, 17-(propionylaminoethyldithioethyl amino-formylethyl)-29, 34-bis-(methoxyformyl)porphyrin (PDTEP, 3) and its cobalt(Ⅱ) complex (Co(Ⅱ)PDTEP, 4) were conveniently synthesized. The disulphide functional group of 4 allowed its stable immobilization on gold electrodes. The modified electrode was characterized by IR and confirmed electrochemically and showed good stability and catalytic activity toward the electro-catalyzed reduction of hydrogen peroxide.
A novel disulphide derivatised deuteroporphyrin 2, 7, 12, 18-tetramethyl-13, 17-(propionylaminoethyldithioethyl amino-formylethyl)-29, 34-bis-(methoxyformyl)porphyrin (PDTEP, 3) and its cobalt(Ⅱ) complex (Co(Ⅱ)PDTEP, 4) were conveniently synthesized. The disulphide functional group of 4 allowed its stable immobilization on gold electrodes. The modified electrode was characterized by IR and confirmed electrochemically and showed good stability and catalytic activity toward the electro-catalyzed reduction of hydrogen peroxide.
2012, 23(2): 161-164
doi: 10.1016/j.cclet.2011.11.019
Abstract:
We have developed simple, cost effective and environmentally benign protocol for the synthesis of 5-substituted 1H-tetrazoles via [2,3] cycloaddition reaction from organic nitriles and sodium azide in glycerol under catalyst free condition. The corresponding 5-substituted 1H-tetrazoles were obtained with good to excellent yields (68-95%).
We have developed simple, cost effective and environmentally benign protocol for the synthesis of 5-substituted 1H-tetrazoles via [2,3] cycloaddition reaction from organic nitriles and sodium azide in glycerol under catalyst free condition. The corresponding 5-substituted 1H-tetrazoles were obtained with good to excellent yields (68-95%).
2012, 23(2): 165-168
doi: 10.1016/j.cclet.2011.11.012
Abstract:
Efficient condensation of resorcinol and various aromatic aldehydes in the presence of RuCl3.nH2O as a homogeneous catalyst under reflux conditions was investigated. It was found that a very simple method afforded good to excellent yields of the desired products.
Efficient condensation of resorcinol and various aromatic aldehydes in the presence of RuCl3.nH2O as a homogeneous catalyst under reflux conditions was investigated. It was found that a very simple method afforded good to excellent yields of the desired products.
2012, 23(2): 169-172
doi: 10.1016/j.cclet.2011.11.004
Abstract:
New 9-(alkyl or aryl)acenaphtho[1,2-b]furan-8-(alky or aryl)amine compounds has herein been reported by one-pot reaction of (acenaphthylen-1-yloxy)trimethylsilane, alkyl and aryl aldehydes, and aryl and alky isocyanides in refluxing DMF.
New 9-(alkyl or aryl)acenaphtho[1,2-b]furan-8-(alky or aryl)amine compounds has herein been reported by one-pot reaction of (acenaphthylen-1-yloxy)trimethylsilane, alkyl and aryl aldehydes, and aryl and alky isocyanides in refluxing DMF.
2012, 23(2): 173-176
doi: 10.1016/j.cclet.2011.11.005
Abstract:
A simple synthesis of novel and known calix[4]resorcinarenes derivatives has been achieved by the condensation of resorcinol and different aromatic arylaldehyde in the presence of catalytic amounts of Fe3O4 nanoparticles under solvent-free conditions. The experimental conditions have been thoroughly optimized and established, allowing significant rate enhancements and good to excellent yields. The reactions can be run safely without using any toxic organic solvents under mild reaction conditions. The Fe3O4 nanoparticles were characterized by powdered x-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR spectroscopy.
A simple synthesis of novel and known calix[4]resorcinarenes derivatives has been achieved by the condensation of resorcinol and different aromatic arylaldehyde in the presence of catalytic amounts of Fe3O4 nanoparticles under solvent-free conditions. The experimental conditions have been thoroughly optimized and established, allowing significant rate enhancements and good to excellent yields. The reactions can be run safely without using any toxic organic solvents under mild reaction conditions. The Fe3O4 nanoparticles were characterized by powdered x-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR spectroscopy.
2012, 23(2): 177-180
doi: 10.1016/j.cclet.2011.10.022
Abstract:
A homologous series of azomethine esters, 4-n-alkanoyloxybenzylidene-4'-bromoanilines possessing even number of carbon atoms at the terminal alkanoyloxy chain (Cn-1H2n-1COO-, n=8, 10, 12, 14, 16, 18) was synthesized and characterized. Whilst n-octanoyloxy to n-dodecanoyloxy derivatives exhibited enantiotropic smectic A and smectic B phases, n-tetradecanoyloxy to n-octadecanoyloxy derivatives possessed enantiotropic smectic A and monotropic smectic B properties. n-Decanoyloxy derivatives demonstrated the optimum exhibition for both smectic A and smectic B phases. It was found that the length of terminal alkanoyloxy chain has an influence on mesomorphic properties.
A homologous series of azomethine esters, 4-n-alkanoyloxybenzylidene-4'-bromoanilines possessing even number of carbon atoms at the terminal alkanoyloxy chain (Cn-1H2n-1COO-, n=8, 10, 12, 14, 16, 18) was synthesized and characterized. Whilst n-octanoyloxy to n-dodecanoyloxy derivatives exhibited enantiotropic smectic A and smectic B phases, n-tetradecanoyloxy to n-octadecanoyloxy derivatives possessed enantiotropic smectic A and monotropic smectic B properties. n-Decanoyloxy derivatives demonstrated the optimum exhibition for both smectic A and smectic B phases. It was found that the length of terminal alkanoyloxy chain has an influence on mesomorphic properties.
2012, 23(2): 181-184
doi: 10.1016/j.cclet.2011.11.006
Abstract:
Two novel and well-defined polyhedral oligomeric silsesquioxanes (POSS) with two same Si8O12 cores and a reactive NH group, namely bridged-POSS (2a and 2b), have been prepared by the traditional ‘corner-capping’ reaction. X-ray diffraction demonstrates that those two POSS have the similar T8 structure. From the thermo-gravimetric analysis, bridged-POSS shows the better thermal degradation stability than the contrastive POSS.
Two novel and well-defined polyhedral oligomeric silsesquioxanes (POSS) with two same Si8O12 cores and a reactive NH group, namely bridged-POSS (2a and 2b), have been prepared by the traditional ‘corner-capping’ reaction. X-ray diffraction demonstrates that those two POSS have the similar T8 structure. From the thermo-gravimetric analysis, bridged-POSS shows the better thermal degradation stability than the contrastive POSS.
2012, 23(2): 185-188
doi: 10.1016/j.cclet.2011.11.007
Abstract:
An efficient palladium-catalyzed copper-and amine-free Sonogashira coupling reaction of aryl bromides and chlorides was studied using a sterically hindered monooxychlorophosphine as new ligand. The use of 2 mol% Pd(OAc)2 in the presence of K2CO3 allows the coupling reaction to proceed at mild condition with good to excellent yields.
An efficient palladium-catalyzed copper-and amine-free Sonogashira coupling reaction of aryl bromides and chlorides was studied using a sterically hindered monooxychlorophosphine as new ligand. The use of 2 mol% Pd(OAc)2 in the presence of K2CO3 allows the coupling reaction to proceed at mild condition with good to excellent yields.
2012, 23(2): 189-192
doi: 10.1016/j.cclet.2011.11.013
Abstract:
A novel dimeric diarylheptanoid, named alpinin A (1), along with two known compounds, 1, 7-diphenyl-5-ol-3-heptanone and 7-(4'-hydroxy-3'-methoxyphenyl)-1-phenyl-4-heptene-3-one, were isolated from the rhizomes of Alpinia officinarum Hance. The structure of compound 1 was elucidated on the basis of spectral analysis, including HR-IT-TOF-MS, 1D and 2D NMR. And a possible biogenetic pathway had been proposed for 1.
A novel dimeric diarylheptanoid, named alpinin A (1), along with two known compounds, 1, 7-diphenyl-5-ol-3-heptanone and 7-(4'-hydroxy-3'-methoxyphenyl)-1-phenyl-4-heptene-3-one, were isolated from the rhizomes of Alpinia officinarum Hance. The structure of compound 1 was elucidated on the basis of spectral analysis, including HR-IT-TOF-MS, 1D and 2D NMR. And a possible biogenetic pathway had been proposed for 1.
2012, 23(2): 193-196
doi: 10.1016/j.cclet.2011.11.014
Abstract:
Two new steroidal sapogenins (1, 2) along with five known steroidal sapogenins were isolated from the acid hydrolysis product of the whole glycoside mixture of Welsh onion (Allium fistulosum L.) seeds. Based on comprehensive spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry, their structures were elucidated as (25R)-19-norspirosta-1, 3, 5 (10)-triene-4-methyl-2-ol (1), (25R)-spirost-1, 4-diene-3-one-2, 6-diol (2), (25R)-spirost-1, 4-diene-3-one-2-ol (3), (25R)-spirost-4-ene-3-one-2-ol (4), yuccagenin (5), gitogenin (6) and tigogenin (7).
Two new steroidal sapogenins (1, 2) along with five known steroidal sapogenins were isolated from the acid hydrolysis product of the whole glycoside mixture of Welsh onion (Allium fistulosum L.) seeds. Based on comprehensive spectroscopic analyses, including 2D NMR spectroscopy and mass spectrometry, their structures were elucidated as (25R)-19-norspirosta-1, 3, 5 (10)-triene-4-methyl-2-ol (1), (25R)-spirost-1, 4-diene-3-one-2, 6-diol (2), (25R)-spirost-1, 4-diene-3-one-2-ol (3), (25R)-spirost-4-ene-3-one-2-ol (4), yuccagenin (5), gitogenin (6) and tigogenin (7).
2012, 23(2): 197-200
doi: 10.1016/j.cclet.2011.10.011
Abstract:
Magnetic Cu2+-chelated silica particles using polyacrylamide as a metal-chelating ligand was developed and used for the immobilization of laccase by coordination. The effect of pH and temperature on the enzymatic property of immobilized laccase and its catalytic capacity for pentachlorophenol (PCP) degradation were evaluated systemically. Compared with free laccase, the immobilized laccase showed improved acid adaptability and thermal stability. The immobilized laccase prepared in this work exhibited a good catalytic capacity for PCP removal from aqueous solutions.
Magnetic Cu2+-chelated silica particles using polyacrylamide as a metal-chelating ligand was developed and used for the immobilization of laccase by coordination. The effect of pH and temperature on the enzymatic property of immobilized laccase and its catalytic capacity for pentachlorophenol (PCP) degradation were evaluated systemically. Compared with free laccase, the immobilized laccase showed improved acid adaptability and thermal stability. The immobilized laccase prepared in this work exhibited a good catalytic capacity for PCP removal from aqueous solutions.
2012, 23(2): 201-204
doi: 10.1016/j.cclet.2011.10.012
Abstract:
A novel electromagnetic induction detector with two inductors for CE was described here. The two inductors were used as signal detection and reference, respectively. The parameters affecting the detector performance (including coil turns, detection distance, excitation frequency and voltage, etc.) were optimized. Under the optimum condition, the feasibility of the detector was examined by analyzing inorganic ions. The fabricated detector showed good linear relationship between the response and the analytes concentrations, with a detection limit of 13 μmol/L for Na+ (S/N=3). A variety of advantages, such as simple construction, ease of operation, and considerably universal response, suggested this novel detector a promising application prospect in analytical area.
A novel electromagnetic induction detector with two inductors for CE was described here. The two inductors were used as signal detection and reference, respectively. The parameters affecting the detector performance (including coil turns, detection distance, excitation frequency and voltage, etc.) were optimized. Under the optimum condition, the feasibility of the detector was examined by analyzing inorganic ions. The fabricated detector showed good linear relationship between the response and the analytes concentrations, with a detection limit of 13 μmol/L for Na+ (S/N=3). A variety of advantages, such as simple construction, ease of operation, and considerably universal response, suggested this novel detector a promising application prospect in analytical area.
2012, 23(2): 205-207
doi: 10.1016/j.cclet.2011.10.014
Abstract:
Meisoindigotin has been demonstrated as a new type of cancer chemotherapeutic agent. N-11C-Meisoindigotin was synthesized by N-11C-methylation of the isoindigotin precursor with 11C-labelled methyl triflate. The decay corrected radiochemical yields were 15-25%,and the specific radioactivity was 1.0-1.2 Ci/μmol at the end of synthesis. The cellular uptake of[N-11C]meisoindigotin was evaluated in four different lung cancer cell lines. Our results showed that the A549, GLC-82, 95D cell lines exhibited higher uptake than 95C cell line after incubation for 60 min. N-11C-Meisoindigotin was a promising candidate for further development as a novel PET radiotracer for imaging of cyclin-dependent kinases (CDKs) and GSK-3β.
Meisoindigotin has been demonstrated as a new type of cancer chemotherapeutic agent. N-11C-Meisoindigotin was synthesized by N-11C-methylation of the isoindigotin precursor with 11C-labelled methyl triflate. The decay corrected radiochemical yields were 15-25%,and the specific radioactivity was 1.0-1.2 Ci/μmol at the end of synthesis. The cellular uptake of[N-11C]meisoindigotin was evaluated in four different lung cancer cell lines. Our results showed that the A549, GLC-82, 95D cell lines exhibited higher uptake than 95C cell line after incubation for 60 min. N-11C-Meisoindigotin was a promising candidate for further development as a novel PET radiotracer for imaging of cyclin-dependent kinases (CDKs) and GSK-3β.
2012, 23(2): 208-212
doi: 10.1016/j.cclet.2011.10.018
Abstract:
Adduct of magnesium tetraphenyl porphyrin (MgTPP) with aniline for colorimetric detection of SO2 was investigated in CH2Cl2 by steady-state fluorescence and UV-vis absorption spectroscopic techniques. The UV-vis spectra showed that the increasing aniline concentrations resulted in red shift of 3 nm for MgTPP Soret absorption band. Once introduced, SO2 competes with MgTPP for aniline, which eventually leads to the release of MgTPP and changes in the solution color/absorption. The fluorescence spectra suggested that MgTPP interacted with aniline to form 1:1 molecular adducts, and showed that the binding of MgTPP with aniline with the binding constants of 1.58-1.64 is not only endothermal but entropy-driven with ΔH=1.622 kJ mol-1, ΔS=9.389 J mol-1 K-1, and ΔG=-1.585 kJ mol-1 at T=298.15 K.
Adduct of magnesium tetraphenyl porphyrin (MgTPP) with aniline for colorimetric detection of SO2 was investigated in CH2Cl2 by steady-state fluorescence and UV-vis absorption spectroscopic techniques. The UV-vis spectra showed that the increasing aniline concentrations resulted in red shift of 3 nm for MgTPP Soret absorption band. Once introduced, SO2 competes with MgTPP for aniline, which eventually leads to the release of MgTPP and changes in the solution color/absorption. The fluorescence spectra suggested that MgTPP interacted with aniline to form 1:1 molecular adducts, and showed that the binding of MgTPP with aniline with the binding constants of 1.58-1.64 is not only endothermal but entropy-driven with ΔH=1.622 kJ mol-1, ΔS=9.389 J mol-1 K-1, and ΔG=-1.585 kJ mol-1 at T=298.15 K.
2012, 23(2): 213-216
doi: 10.1016/j.cclet.2011.10.016
Abstract:
The homogeneous electrocatalytic oxidation of hydrazine (HZ) has been studied by indigocarmine (IND) as a mediator at the surface of TiO2 nanoparticles modified carbon paste electrode (TNMCPE). Cyclic voltammetry was used to study the electrochemical behavior of IND at different scan rates. The voltammetric response of the modified electrode was linear against the concentration of HZ in the ranges of 3.0×10-8 mol/L-7.0×10-6 mol/L with differential pulse voltammetry method. The detection limit (3σ) was determined as 27.3 nmol/L. To evaluate the applicability of the proposed method to real samples, the modified CPE was applied to the determination of HZ in water samples.
The homogeneous electrocatalytic oxidation of hydrazine (HZ) has been studied by indigocarmine (IND) as a mediator at the surface of TiO2 nanoparticles modified carbon paste electrode (TNMCPE). Cyclic voltammetry was used to study the electrochemical behavior of IND at different scan rates. The voltammetric response of the modified electrode was linear against the concentration of HZ in the ranges of 3.0×10-8 mol/L-7.0×10-6 mol/L with differential pulse voltammetry method. The detection limit (3σ) was determined as 27.3 nmol/L. To evaluate the applicability of the proposed method to real samples, the modified CPE was applied to the determination of HZ in water samples.
2012, 23(2): 217-220
doi: 10.1016/j.cclet.2011.11.001
Abstract:
A novel unsymmetrical squaramide-linked squaraine dye (SQ) has been synthesized through squaramide 3 and semisquaraine 6. The molecular structure of SQ has been characterized by 1H NMR, IR and MS. Due to the influence of the hydrogen bond and the solvent effect, SQ exhibits unique spectral properties compared with typical squaraine dyes. For its excellent ability of binding primary amine, SQ is a promising receptor of recognizing primary amine.
A novel unsymmetrical squaramide-linked squaraine dye (SQ) has been synthesized through squaramide 3 and semisquaraine 6. The molecular structure of SQ has been characterized by 1H NMR, IR and MS. Due to the influence of the hydrogen bond and the solvent effect, SQ exhibits unique spectral properties compared with typical squaraine dyes. For its excellent ability of binding primary amine, SQ is a promising receptor of recognizing primary amine.
2012, 23(2): 221-224
doi: 10.1016/j.cclet.2011.11.010
Abstract:
The vitamin C (VC) in crops was successfully determined using ascorbate oxidase (AO) electrochemical biosensor based on the biocompatible poly(3, 4-ethylenedioxythiophene) (PEDOT) matrices, which was easily prepared by one-step electrodeposition technique in ionic liquid microemulsions. The fabricated biosensor displayed excellent bioelectrocatalytic performance to the oxidation of VC, wide linear range, low detection limit, fast response time, good operational and storage stability, the good results of the determination of VC in vegetable crops indicated that the fabricated biosensor will be a good candidate for the physiological and biochemical studies of crops in near future.
The vitamin C (VC) in crops was successfully determined using ascorbate oxidase (AO) electrochemical biosensor based on the biocompatible poly(3, 4-ethylenedioxythiophene) (PEDOT) matrices, which was easily prepared by one-step electrodeposition technique in ionic liquid microemulsions. The fabricated biosensor displayed excellent bioelectrocatalytic performance to the oxidation of VC, wide linear range, low detection limit, fast response time, good operational and storage stability, the good results of the determination of VC in vegetable crops indicated that the fabricated biosensor will be a good candidate for the physiological and biochemical studies of crops in near future.
2012, 23(2): 225-228
doi: 10.1016/j.cclet.2011.09.025
Abstract:
A rapid, sensitive, selective and reliable strip assay based on DNA-functionalized gold nanoparticles for Hg2+ detection has been developed, with a detection limit 5 nmol/L. The measurement principle was based on thymine-Hg2+-thymine (T-Hg2+-T) coordination chemistry and streptavidin-biotin interaction. The major advantages of this assay are that results can be read visually without any instrument in less than 10 min and that it does not require any sample pretreatment.
A rapid, sensitive, selective and reliable strip assay based on DNA-functionalized gold nanoparticles for Hg2+ detection has been developed, with a detection limit 5 nmol/L. The measurement principle was based on thymine-Hg2+-thymine (T-Hg2+-T) coordination chemistry and streptavidin-biotin interaction. The major advantages of this assay are that results can be read visually without any instrument in less than 10 min and that it does not require any sample pretreatment.
2012, 23(2): 229-232
doi: 10.1016/j.cclet.2011.11.003
Abstract:
A highly selective nitric oxide (NO) sensor is fabricated and applied to devise an enhanced flow injection analysis (FIA) system for S-nitrosothiols (RSNOs) measurement in biological samples. The NO sensor is prepared using a polytetrafluoroethylene (PTFE) gas-permeable membrane loaded with Teflon AF® solution, a copolymer of tetrafluoroethylene and 2, 2-bis(trifluoroethylene)-4, 5-difluoro-1, 3-dioxole, to improve selectivity. This method is much simpler and possesses good performance over a wide range of RSNOs concentrations. Standard deviation for three parallel measurements of blood plasma is 4.0%. The use of the gas sensing configuration as the detector enhances selectivity of the FIA measurement vs. using less selective electrochemical detectors that do not use PTFE/Teflon type outer membranes.
A highly selective nitric oxide (NO) sensor is fabricated and applied to devise an enhanced flow injection analysis (FIA) system for S-nitrosothiols (RSNOs) measurement in biological samples. The NO sensor is prepared using a polytetrafluoroethylene (PTFE) gas-permeable membrane loaded with Teflon AF® solution, a copolymer of tetrafluoroethylene and 2, 2-bis(trifluoroethylene)-4, 5-difluoro-1, 3-dioxole, to improve selectivity. This method is much simpler and possesses good performance over a wide range of RSNOs concentrations. Standard deviation for three parallel measurements of blood plasma is 4.0%. The use of the gas sensing configuration as the detector enhances selectivity of the FIA measurement vs. using less selective electrochemical detectors that do not use PTFE/Teflon type outer membranes.
2012, 23(2): 233-236
doi: 10.1016/j.cclet.2011.10.021
Abstract:
A polymeric membrane ion-selective electrode for determination of heparin is described in this paper. Protamine is incorporated into the organic membrane phase and functions as sensing element for selective recognition of heparin. The proposed membrane electrode exhibits high selectivity for heparin over lipophilic anions such as thiocyanide and salicylate. The potentiometric response to the concentration of heparin is linear in the range of 0.01-0.4 U/mL and a lower detection limit of 0.005 U/mL is achieved.
A polymeric membrane ion-selective electrode for determination of heparin is described in this paper. Protamine is incorporated into the organic membrane phase and functions as sensing element for selective recognition of heparin. The proposed membrane electrode exhibits high selectivity for heparin over lipophilic anions such as thiocyanide and salicylate. The potentiometric response to the concentration of heparin is linear in the range of 0.01-0.4 U/mL and a lower detection limit of 0.005 U/mL is achieved.
2012, 23(2): 237-240
doi: 10.1016/j.cclet.2011.10.023
Abstract:
A carbon paste electrode (CPE) chemically modified with multiwall carbon nanotubes and ferrocene (FC) was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine (CA) and folic acid (FA). This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of CA. The peaks current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200 μmol/L CA and 5.0-700 μmol/L FA. The detection limits for CA and FA were 0.3 μmol/L and 2.0 μmol/L, respectively. The diffusion coefficient (D) and transfer coefficient (α) of CA were also determined. These conditions are sufficient to allow determination of CA and FA both individually and simultaneously.
A carbon paste electrode (CPE) chemically modified with multiwall carbon nanotubes and ferrocene (FC) was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine (CA) and folic acid (FA). This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of CA. The peaks current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200 μmol/L CA and 5.0-700 μmol/L FA. The detection limits for CA and FA were 0.3 μmol/L and 2.0 μmol/L, respectively. The diffusion coefficient (D) and transfer coefficient (α) of CA were also determined. These conditions are sufficient to allow determination of CA and FA both individually and simultaneously.
2012, 23(2): 241-244
doi: 10.1016/j.cclet.2011.10.013
Abstract:
The urethane reaction of o-hydroxybenzyl alcohol with phenyl isocyanate was monitored with in situ FT-IR. Dibutyltin dilaurate was used as catalyst and its amount effect was investigated. It was found that there was an obvious induction period before reaction began. It was interesting that the time of induction period climbed up and then declined with the increase of dibutyltin dilaurate. When the concentration of dibutyltin dilaurate reached 9.58×10-5 mol/L, the induction period disappeared completely and hereafter did not appear any more. Furthermore, the urethane reaction kinetics was studied. When the concentration of dibutyltin dilaurate increased, the reaction rate of phenolic group (k1) increased sharply, but the reaction rate of alcoholic group (k2) appeared of little change on the whole. K1 increased about 20-fold, yet k2 increased about 2-fold when the concentration of dibutyltin dilaurate varied from 9.58×10-6 mol/L to 1.92×10-4 mol/L, which made the value of k1/k2 enlarge.
The urethane reaction of o-hydroxybenzyl alcohol with phenyl isocyanate was monitored with in situ FT-IR. Dibutyltin dilaurate was used as catalyst and its amount effect was investigated. It was found that there was an obvious induction period before reaction began. It was interesting that the time of induction period climbed up and then declined with the increase of dibutyltin dilaurate. When the concentration of dibutyltin dilaurate reached 9.58×10-5 mol/L, the induction period disappeared completely and hereafter did not appear any more. Furthermore, the urethane reaction kinetics was studied. When the concentration of dibutyltin dilaurate increased, the reaction rate of phenolic group (k1) increased sharply, but the reaction rate of alcoholic group (k2) appeared of little change on the whole. K1 increased about 20-fold, yet k2 increased about 2-fold when the concentration of dibutyltin dilaurate varied from 9.58×10-6 mol/L to 1.92×10-4 mol/L, which made the value of k1/k2 enlarge.
2012, 23(2): 245-248
doi: 10.1016/j.cclet.2011.10.019
Abstract:
The new hyper cross-linked chelating resin NDWJN2 modified with carboxyl groups was prepared for removal of Cu2+ and Ni2+ from water. NDWJN2 was characterized using BET, SEM and FT-IR spectroscopy. Comparing with commercial resins D113 and IRC84, NDWJN2 could remove Cu2+ and Ni2+ from water more effectively. Langmuir model could fit adsorption isotherms well.
The new hyper cross-linked chelating resin NDWJN2 modified with carboxyl groups was prepared for removal of Cu2+ and Ni2+ from water. NDWJN2 was characterized using BET, SEM and FT-IR spectroscopy. Comparing with commercial resins D113 and IRC84, NDWJN2 could remove Cu2+ and Ni2+ from water more effectively. Langmuir model could fit adsorption isotherms well.
2012, 23(2): 249-252
doi: 10.1016/j.cclet.2011.11.020
Abstract:
Electrocrystallizations of copper from both CuCl2 silica sol and aqueous solutions were studied by the chronoamperometry technique. It was found that current density contributions of the double-layer charging (iDL) in current-time transients (CTTs) from both of the solutions were large. An adsorption-nucleation based model was proposed to analyze quantitatively the CTTs, by which copper electrocrystallization mechanism was characterized as progressive nucleation with 3D growth (3DP) under diffusion control. The diffusion coefficient of copper ions and the AN∞ products in aqueous solutions were larger than that in silica sols, which indicated that copper nucleation was inhibited in sol solution. The large iDLDL may be resulted from the adsorption of chloride ions on the electrode surface.
Electrocrystallizations of copper from both CuCl2 silica sol and aqueous solutions were studied by the chronoamperometry technique. It was found that current density contributions of the double-layer charging (iDL) in current-time transients (CTTs) from both of the solutions were large. An adsorption-nucleation based model was proposed to analyze quantitatively the CTTs, by which copper electrocrystallization mechanism was characterized as progressive nucleation with 3D growth (3DP) under diffusion control. The diffusion coefficient of copper ions and the AN∞ products in aqueous solutions were larger than that in silica sols, which indicated that copper nucleation was inhibited in sol solution. The large iDLDL may be resulted from the adsorption of chloride ions on the electrode surface.
